[mesa.git] / src / mesa / state_tracker / st_cb_texture.c

/**************************************************************************
 * 
 * Copyright 2007 VMware, Inc.
 * All Rights Reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 * 
 **************************************************************************/

#include <stdio.h>
#include "main/bufferobj.h"
#include "main/enums.h"
#include "main/errors.h"
#include "main/fbobject.h"
#include "main/formats.h"
#include "main/format_utils.h"
#include "main/glformats.h"
#include "main/image.h"
#include "main/imports.h"
#include "main/macros.h"
#include "main/mipmap.h"
#include "main/pack.h"
#include "main/pbo.h"
#include "main/pixeltransfer.h"
#include "main/texcompress.h"
#include "main/texcompress_astc.h"
#include "main/texcompress_etc.h"
#include "main/texgetimage.h"
#include "main/teximage.h"
#include "main/texobj.h"
#include "main/texstore.h"

#include "state_tracker/st_debug.h"
#include "state_tracker/st_context.h"
#include "state_tracker/st_cb_bitmap.h"
#include "state_tracker/st_cb_fbo.h"
#include "state_tracker/st_cb_flush.h"
#include "state_tracker/st_cb_texture.h"
#include "state_tracker/st_cb_bufferobjects.h"
#include "state_tracker/st_cb_memoryobjects.h"
#include "state_tracker/st_format.h"
#include "state_tracker/st_pbo.h"
#include "state_tracker/st_texture.h"
#include "state_tracker/st_gen_mipmap.h"
#include "state_tracker/st_atom.h"
#include "state_tracker/st_sampler_view.h"

#include "pipe/p_context.h"
#include "pipe/p_defines.h"
#include "util/u_inlines.h"
#include "util/u_upload_mgr.h"
#include "pipe/p_shader_tokens.h"
#include "util/u_tile.h"
#include "util/u_format.h"
#include "util/u_surface.h"
#include "util/u_sampler.h"
#include "util/u_math.h"
#include "util/u_box.h"
#include "util/u_simple_shaders.h"
#include "cso_cache/cso_context.h"
#include "tgsi/tgsi_ureg.h"

#define DBG if (0) printf


enum pipe_texture_target
gl_target_to_pipe(GLenum target)
{
   switch (target) {
   case GL_TEXTURE_1D:
   case GL_PROXY_TEXTURE_1D:
      return PIPE_TEXTURE_1D;
   case GL_TEXTURE_2D:
   case GL_PROXY_TEXTURE_2D:
   case GL_TEXTURE_EXTERNAL_OES:
   case GL_TEXTURE_2D_MULTISAMPLE:
   case GL_PROXY_TEXTURE_2D_MULTISAMPLE:
      return PIPE_TEXTURE_2D;
   case GL_TEXTURE_RECTANGLE_NV:
   case GL_PROXY_TEXTURE_RECTANGLE_NV:
      return PIPE_TEXTURE_RECT;
   case GL_TEXTURE_3D:
   case GL_PROXY_TEXTURE_3D:
      return PIPE_TEXTURE_3D;
   case GL_TEXTURE_CUBE_MAP_ARB:
   case GL_PROXY_TEXTURE_CUBE_MAP_ARB:
   case GL_TEXTURE_CUBE_MAP_POSITIVE_X:
   case GL_TEXTURE_CUBE_MAP_NEGATIVE_X:
   case GL_TEXTURE_CUBE_MAP_POSITIVE_Y:
   case GL_TEXTURE_CUBE_MAP_NEGATIVE_Y:
   case GL_TEXTURE_CUBE_MAP_POSITIVE_Z:
   case GL_TEXTURE_CUBE_MAP_NEGATIVE_Z:
      return PIPE_TEXTURE_CUBE;
   case GL_TEXTURE_1D_ARRAY_EXT:
   case GL_PROXY_TEXTURE_1D_ARRAY_EXT:
      return PIPE_TEXTURE_1D_ARRAY;
   case GL_TEXTURE_2D_ARRAY_EXT:
   case GL_PROXY_TEXTURE_2D_ARRAY_EXT:
   case GL_TEXTURE_2D_MULTISAMPLE_ARRAY:
   case GL_PROXY_TEXTURE_2D_MULTISAMPLE_ARRAY:
      return PIPE_TEXTURE_2D_ARRAY;
   case GL_TEXTURE_BUFFER:
      return PIPE_BUFFER;
   case GL_TEXTURE_CUBE_MAP_ARRAY:
   case GL_PROXY_TEXTURE_CUBE_MAP_ARRAY:
      return PIPE_TEXTURE_CUBE_ARRAY;
   default:
      assert(0);
      return 0;
   }
}


/** called via ctx->Driver.NewTextureImage() */
static struct gl_texture_image *
st_NewTextureImage(struct gl_context * ctx)
{
   DBG("%s\n", __func__);
   (void) ctx;
   return (struct gl_texture_image *) ST_CALLOC_STRUCT(st_texture_image);
}


/** called via ctx->Driver.DeleteTextureImage() */
static void
st_DeleteTextureImage(struct gl_context * ctx, struct gl_texture_image *img)
{
   /* nothing special (yet) for st_texture_image */
   _mesa_delete_texture_image(ctx, img);
}


/** called via ctx->Driver.NewTextureObject() */
static struct gl_texture_object *
st_NewTextureObject(struct gl_context * ctx, GLuint name, GLenum target)
{
   struct st_texture_object *obj = ST_CALLOC_STRUCT(st_texture_object);
   if (!obj)
      return NULL;

   /* Pre-allocate a sampler views container to save a branch in the fast path. */
   obj->sampler_views = calloc(1, sizeof(struct st_sampler_views) + sizeof(struct st_sampler_view));
   if (!obj->sampler_views) {
      free(obj);
      return NULL;
   }
   obj->sampler_views->max = 1;

   DBG("%s\n", __func__);
   _mesa_initialize_texture_object(ctx, &obj->base, name, target);

   simple_mtx_init(&obj->validate_mutex, mtx_plain);
   obj->needs_validation = true;

   return &obj->base;
}

/** called via ctx->Driver.DeleteTextureObject() */
static void 
st_DeleteTextureObject(struct gl_context *ctx,
                       struct gl_texture_object *texObj)
{
   struct st_context *st = st_context(ctx);
   struct st_texture_object *stObj = st_texture_object(texObj);

   pipe_resource_reference(&stObj->pt, NULL);
   st_texture_release_all_sampler_views(st, stObj);
   st_texture_free_sampler_views(stObj);
   simple_mtx_destroy(&stObj->validate_mutex);
   _mesa_delete_texture_object(ctx, texObj);
}


/** called via ctx->Driver.FreeTextureImageBuffer() */
static void
st_FreeTextureImageBuffer(struct gl_context *ctx,
                          struct gl_texture_image *texImage)
{
   struct st_context *st = st_context(ctx);
   struct st_texture_object *stObj = st_texture_object(texImage->TexObject);
   struct st_texture_image *stImage = st_texture_image(texImage);

   DBG("%s\n", __func__);

   if (stImage->pt) {
      pipe_resource_reference(&stImage->pt, NULL);
   }

   free(stImage->transfer);
   stImage->transfer = NULL;
   stImage->num_transfers = 0;

   if (stImage->compressed_data) {
      free(stImage->compressed_data);
      stImage->compressed_data = NULL;
   }

   /* if the texture image is being deallocated, the structure of the
    * texture is changing so we'll likely need a new sampler view.
    */
   st_texture_release_all_sampler_views(st, stObj);
}

bool
st_compressed_format_fallback(struct st_context *st, mesa_format format)
{
   if (format == MESA_FORMAT_ETC1_RGB8)
      return !st->has_etc1;

   if (_mesa_is_format_etc2(format))
      return !st->has_etc2;

   if (_mesa_is_format_astc_2d(format))
      return !st->has_astc_2d_ldr;

   return false;
}

static void
compressed_tex_fallback_allocate(struct st_context *st,
                                 struct st_texture_image *stImage)
{
   struct gl_texture_image *texImage = &stImage->base;

   if (!st_compressed_format_fallback(st, texImage->TexFormat))
      return;

   if (stImage->compressed_data)
      free(stImage->compressed_data);

   unsigned data_size = _mesa_format_image_size(texImage->TexFormat,
                                                texImage->Width2,
                                                texImage->Height2,
                                                texImage->Depth2);

   stImage->compressed_data =
      malloc(data_size * _mesa_num_tex_faces(texImage->TexObject->Target));
}

/** called via ctx->Driver.MapTextureImage() */
static void
st_MapTextureImage(struct gl_context *ctx,
                   struct gl_texture_image *texImage,
                   GLuint slice, GLuint x, GLuint y, GLuint w, GLuint h,
                   GLbitfield mode,
                   GLubyte **mapOut, GLint *rowStrideOut)
{
   struct st_context *st = st_context(ctx);
   struct st_texture_image *stImage = st_texture_image(texImage);
   GLubyte *map;
   struct pipe_transfer *transfer;

   /* Check for unexpected flags */
   assert((mode & ~(GL_MAP_READ_BIT |
                    GL_MAP_WRITE_BIT |
                    GL_MAP_INVALIDATE_RANGE_BIT)) == 0);

   const enum pipe_transfer_usage transfer_flags =
      st_access_flags_to_transfer_flags(mode, false);

   map = st_texture_image_map(st, stImage, transfer_flags, x, y, slice, w, h, 1,
                              &transfer);
   if (map) {
      if (st_compressed_format_fallback(st, texImage->TexFormat)) {
         /* Some compressed formats don't have to be supported by drivers,
          * and st/mesa transparently handles decompression on upload (Unmap),
          * so that drivers don't see the compressed formats.
          *
          * We store the compressed data (it's needed for glGetCompressedTex-
          * Image and image copies in OES_copy_image).
          */
         unsigned z = transfer->box.z;
         struct st_texture_image_transfer *itransfer = &stImage->transfer[z];

         unsigned blk_w, blk_h;
         _mesa_get_format_block_size(texImage->TexFormat, &blk_w, &blk_h);

         unsigned y_blocks = DIV_ROUND_UP(texImage->Height2, blk_h);
         unsigned stride = *rowStrideOut = itransfer->temp_stride =
            _mesa_format_row_stride(texImage->TexFormat, texImage->Width2);
         unsigned block_size = _mesa_get_format_bytes(texImage->TexFormat);

         *mapOut = itransfer->temp_data =
            stImage->compressed_data +
            (z * y_blocks + (y / blk_h)) * stride +
            (x / blk_w) * block_size;
         itransfer->map = map;
      }
      else {
         /* supported mapping */
         *mapOut = map;
         *rowStrideOut = transfer->stride;
      }
   }
   else {
      *mapOut = NULL;
      *rowStrideOut = 0;
   }
}


/** called via ctx->Driver.UnmapTextureImage() */
static void
st_UnmapTextureImage(struct gl_context *ctx,
                     struct gl_texture_image *texImage,
                     GLuint slice)
{
   struct st_context *st = st_context(ctx);
   struct st_texture_image *stImage  = st_texture_image(texImage);

   if (st_compressed_format_fallback(st, texImage->TexFormat)) {
      /* Decompress the compressed image on upload if the driver doesn't
       * support the compressed format. */
      unsigned z = slice + stImage->base.Face;
      struct st_texture_image_transfer *itransfer = &stImage->transfer[z];
      struct pipe_transfer *transfer = itransfer->transfer;

      assert(z == transfer->box.z);

      if (transfer->usage & PIPE_TRANSFER_WRITE) {
         if (texImage->TexFormat == MESA_FORMAT_ETC1_RGB8) {
            _mesa_etc1_unpack_rgba8888(itransfer->map, transfer->stride,
                                       itransfer->temp_data,
                                       itransfer->temp_stride,
                                       transfer->box.width, transfer->box.height);
         } else if (_mesa_is_format_etc2(texImage->TexFormat)) {
            bool bgra = stImage->pt->format == PIPE_FORMAT_B8G8R8A8_SRGB;
            _mesa_unpack_etc2_format(itransfer->map, transfer->stride,
                                     itransfer->temp_data, itransfer->temp_stride,
                                     transfer->box.width, transfer->box.height,
                                     texImage->TexFormat,
                                     bgra);
         } else if (_mesa_is_format_astc_2d(texImage->TexFormat)) {
            _mesa_unpack_astc_2d_ldr(itransfer->map, transfer->stride,
                                     itransfer->temp_data, itransfer->temp_stride,
                                     transfer->box.width, transfer->box.height,
                                     texImage->TexFormat);
         } else {
            unreachable("unexpected format for a compressed format fallback");
         }
      }

      itransfer->temp_data = NULL;
      itransfer->temp_stride = 0;
      itransfer->map = 0;
   }

   st_texture_image_unmap(st, stImage, slice);
}


/**
 * Return default texture resource binding bitmask for the given format.
 */
static GLuint
default_bindings(struct st_context *st, enum pipe_format format)
{
   struct pipe_screen *screen = st->pipe->screen;
   const unsigned target = PIPE_TEXTURE_2D;
   unsigned bindings;

   if (util_format_is_depth_or_stencil(format))
      bindings = PIPE_BIND_SAMPLER_VIEW | PIPE_BIND_DEPTH_STENCIL;
   else
      bindings = PIPE_BIND_SAMPLER_VIEW | PIPE_BIND_RENDER_TARGET;

   if (screen->is_format_supported(screen, format, target, 0, bindings))
      return bindings;
   else {
      /* Try non-sRGB. */
      format = util_format_linear(format);

      if (screen->is_format_supported(screen, format, target, 0, bindings))
         return bindings;
      else
         return PIPE_BIND_SAMPLER_VIEW;
   }
}


/**
 * Given the size of a mipmap image, try to compute the size of the level=0
 * mipmap image.
 *
 * Note that this isn't always accurate for odd-sized, non-POW textures.
 * For example, if level=1 and width=40 then the level=0 width may be 80 or 81.
 *
 * \return GL_TRUE for success, GL_FALSE for failure
 */
static GLboolean
guess_base_level_size(GLenum target,
                      GLuint width, GLuint height, GLuint depth, GLuint level,
                      GLuint *width0, GLuint *height0, GLuint *depth0)
{ 
   assert(width >= 1);
   assert(height >= 1);
   assert(depth >= 1);

   if (level > 0) {
      /* Guess the size of the base level.
       * Depending on the image's size, we can't always make a guess here.
       */
      switch (target) {
      case GL_TEXTURE_1D:
      case GL_TEXTURE_1D_ARRAY:
         width <<= level;
         break;

      case GL_TEXTURE_2D:
      case GL_TEXTURE_2D_ARRAY:
         /* We can't make a good guess here, because the base level dimensions
          * can be non-square.
          */
         if (width == 1 || height == 1) {
            return GL_FALSE;
         }
         width <<= level;
         height <<= level;
         break;

      case GL_TEXTURE_CUBE_MAP:
      case GL_TEXTURE_CUBE_MAP_ARRAY:
         width <<= level;
         height <<= level;
         break;

      case GL_TEXTURE_3D:
         /* We can't make a good guess here, because the base level dimensions
          * can be non-cube.
          */
         if (width == 1 || height == 1 || depth == 1) {
            return GL_FALSE;
         }
         width <<= level;
         height <<= level;
         depth <<= level;
         break;

      case GL_TEXTURE_RECTANGLE:
         break;

      default:
         assert(0);
      }
   }

   *width0 = width;
   *height0 = height;
   *depth0 = depth;

   return GL_TRUE;
}


/**
 * Try to determine whether we should allocate memory for a full texture
 * mipmap.  The problem is when we get a glTexImage(level=0) call, we
 * can't immediately know if other mipmap levels are coming next.  Here
 * we try to guess whether to allocate memory for a mipmap or just the
 * 0th level.
 *
 * If we guess incorrectly here we'll later reallocate the right amount of
 * memory either in st_AllocTextureImageBuffer() or st_finalize_texture().
 *
 * \param stObj  the texture object we're going to allocate memory for.
 * \param stImage  describes the incoming image which we need to store.
 */
static boolean
allocate_full_mipmap(const struct st_texture_object *stObj,
                     const struct st_texture_image *stImage)
{
   switch (stObj->base.Target) {
   case GL_TEXTURE_RECTANGLE_NV:
   case GL_TEXTURE_BUFFER:
   case GL_TEXTURE_EXTERNAL_OES:
   case GL_TEXTURE_2D_MULTISAMPLE:
   case GL_TEXTURE_2D_MULTISAMPLE_ARRAY:
      /* these texture types cannot be mipmapped */
      return FALSE;
   }

   if (stImage->base.Level > 0 || stObj->base.GenerateMipmap)
      return TRUE;

   if (stImage->base._BaseFormat == GL_DEPTH_COMPONENT ||
       stImage->base._BaseFormat == GL_DEPTH_STENCIL_EXT)
      /* depth/stencil textures are seldom mipmapped */
      return FALSE;

   if (stObj->base.BaseLevel == 0 && stObj->base.MaxLevel == 0)
      return FALSE;

   if (stObj->base.Sampler.MinFilter == GL_NEAREST ||
       stObj->base.Sampler.MinFilter == GL_LINEAR)
      /* not a mipmap minification filter */
      return FALSE;

   if (stObj->base.Target == GL_TEXTURE_3D)
      /* 3D textures are seldom mipmapped */
      return FALSE;

   return TRUE;
}


/**
 * Try to allocate a pipe_resource object for the given st_texture_object.
 *
 * We use the given st_texture_image as a clue to determine the size of the
 * mipmap image at level=0.
 *
 * \return GL_TRUE for success, GL_FALSE if out of memory.
 */
static GLboolean
guess_and_alloc_texture(struct st_context *st,
                        struct st_texture_object *stObj,
                        const struct st_texture_image *stImage)
{
   const struct gl_texture_image *firstImage;
   GLuint lastLevel, width, height, depth;
   GLuint bindings;
   unsigned ptWidth;
   uint16_t ptHeight, ptDepth, ptLayers;
   enum pipe_format fmt;
   bool guessed_box = false;

   DBG("%s\n", __func__);

   assert(!stObj->pt);

   /* If a base level image with compatible size exists, use that as our guess.
    */
   firstImage = _mesa_base_tex_image(&stObj->base);
   if (firstImage &&
       firstImage->Width2 > 0 &&
       firstImage->Height2 > 0 &&
       firstImage->Depth2 > 0 &&
       guess_base_level_size(stObj->base.Target,
                             firstImage->Width2,
                             firstImage->Height2,
                             firstImage->Depth2,
                             firstImage->Level,
                             &width, &height, &depth)) {
      if (stImage->base.Width2 == u_minify(width, stImage->base.Level) &&
          stImage->base.Height2 == u_minify(height, stImage->base.Level) &&
          stImage->base.Depth2 == u_minify(depth, stImage->base.Level))
         guessed_box = true;
   }

   if (!guessed_box)
      guessed_box = guess_base_level_size(stObj->base.Target,
                                          stImage->base.Width2,
                                          stImage->base.Height2,
                                          stImage->base.Depth2,
                                          stImage->base.Level,
                                          &width, &height, &depth);

   if (!guessed_box) {
      /* we can't determine the image size at level=0 */
      /* this is not an out of memory error */
      return GL_TRUE;
   }

   /* At this point, (width x height x depth) is the expected size of
    * the level=0 mipmap image.
    */

   /* Guess a reasonable value for lastLevel.  With OpenGL we have no
    * idea how many mipmap levels will be in a texture until we start
    * to render with it.  Make an educated guess here but be prepared
    * to re-allocating a texture buffer with space for more (or fewer)
    * mipmap levels later.
    */
   if (allocate_full_mipmap(stObj, stImage)) {
      /* alloc space for a full mipmap */
      lastLevel = _mesa_get_tex_max_num_levels(stObj->base.Target,
                                               width, height, depth) - 1;
   }
   else {
      /* only alloc space for a single mipmap level */
      lastLevel = 0;
   }

   fmt = st_mesa_format_to_pipe_format(st, stImage->base.TexFormat);

   bindings = default_bindings(st, fmt);

   st_gl_texture_dims_to_pipe_dims(stObj->base.Target,
                                   width, height, depth,
                                   &ptWidth, &ptHeight, &ptDepth, &ptLayers);

   stObj->pt = st_texture_create(st,
                                 gl_target_to_pipe(stObj->base.Target),
                                 fmt,
                                 lastLevel,
                                 ptWidth,
                                 ptHeight,
                                 ptDepth,
                                 ptLayers, 0,
                                 bindings);

   stObj->lastLevel = lastLevel;

   DBG("%s returning %d\n", __func__, (stObj->pt != NULL));

   return stObj->pt != NULL;
}


/**
 * Called via ctx->Driver.AllocTextureImageBuffer().
 * If the texture object/buffer already has space for the indicated image,
 * we're done.  Otherwise, allocate memory for the new texture image.
 */
static GLboolean
st_AllocTextureImageBuffer(struct gl_context *ctx,
                           struct gl_texture_image *texImage)
{
   struct st_context *st = st_context(ctx);
   struct st_texture_image *stImage = st_texture_image(texImage);
   struct st_texture_object *stObj = st_texture_object(texImage->TexObject);
   const GLuint level = texImage->Level;
   GLuint width = texImage->Width;
   GLuint height = texImage->Height;
   GLuint depth = texImage->Depth;

   DBG("%s\n", __func__);

   assert(!stImage->pt); /* xxx this might be wrong */

   stObj->needs_validation = true;

   compressed_tex_fallback_allocate(st, stImage);

   /* Look if the parent texture object has space for this image */
   if (stObj->pt &&
       level <= stObj->pt->last_level &&
       st_texture_match_image(st, stObj->pt, texImage)) {
      /* this image will fit in the existing texture object's memory */
      pipe_resource_reference(&stImage->pt, stObj->pt);
      return GL_TRUE;
   }

   /* The parent texture object does not have space for this image */

   pipe_resource_reference(&stObj->pt, NULL);
   st_texture_release_all_sampler_views(st, stObj);

   if (!guess_and_alloc_texture(st, stObj, stImage)) {
      /* Probably out of memory.
       * Try flushing any pending rendering, then retry.
       */
      st_finish(st);
      if (!guess_and_alloc_texture(st, stObj, stImage)) {
         _mesa_error(ctx, GL_OUT_OF_MEMORY, "glTexImage");
         return GL_FALSE;
      }
   }

   if (stObj->pt &&
       st_texture_match_image(st, stObj->pt, texImage)) {
      /* The image will live in the object's mipmap memory */
      pipe_resource_reference(&stImage->pt, stObj->pt);
      assert(stImage->pt);
      return GL_TRUE;
   }
   else {
      /* Create a new, temporary texture/resource/buffer to hold this
       * one texture image.  Note that when we later access this image
       * (either for mapping or copying) we'll want to always specify
       * mipmap level=0, even if the image represents some other mipmap
       * level.
       */
      enum pipe_format format =
         st_mesa_format_to_pipe_format(st, texImage->TexFormat);
      GLuint bindings = default_bindings(st, format);
      unsigned ptWidth;
      uint16_t ptHeight, ptDepth, ptLayers;

      st_gl_texture_dims_to_pipe_dims(stObj->base.Target,
                                      width, height, depth,
                                      &ptWidth, &ptHeight, &ptDepth, &ptLayers);

      stImage->pt = st_texture_create(st,
                                      gl_target_to_pipe(stObj->base.Target),
                                      format,
                                      0, /* lastLevel */
                                      ptWidth,
                                      ptHeight,
                                      ptDepth,
                                      ptLayers, 0,
                                      bindings);
      return stImage->pt != NULL;
   }
}


/**
 * Preparation prior to glTexImage.  Basically check the 'surface_based'
 * field and switch to a "normal" tex image if necessary.
 */
static void
prep_teximage(struct gl_context *ctx, struct gl_texture_image *texImage,
              GLenum format, GLenum type)
{
   struct gl_texture_object *texObj = texImage->TexObject;
   struct st_texture_object *stObj = st_texture_object(texObj);

   /* switch to "normal" */
   if (stObj->surface_based) {
      const GLenum target = texObj->Target;
      const GLuint level = texImage->Level;
      mesa_format texFormat;

      assert(!st_texture_image(texImage)->pt);
      _mesa_clear_texture_object(ctx, texObj, texImage);
      stObj->layer_override = 0;
      stObj->level_override = 0;
      pipe_resource_reference(&stObj->pt, NULL);

      /* oops, need to init this image again */
      texFormat = _mesa_choose_texture_format(ctx, texObj, target, level,
                                              texImage->InternalFormat, format,
                                              type);

      _mesa_init_teximage_fields(ctx, texImage,
                                 texImage->Width, texImage->Height,
                                 texImage->Depth, texImage->Border,
                                 texImage->InternalFormat, texFormat);

      stObj->surface_based = GL_FALSE;
   }
}


/**
 * Return a writemask for the gallium blit. The parameters can be base
 * formats or "format" from glDrawPixels/glTexImage/glGetTexImage.
 */
unsigned
st_get_blit_mask(GLenum srcFormat, GLenum dstFormat)
{
   switch (dstFormat) {
   case GL_DEPTH_STENCIL:
      switch (srcFormat) {
      case GL_DEPTH_STENCIL:
         return PIPE_MASK_ZS;
      case GL_DEPTH_COMPONENT:
         return PIPE_MASK_Z;
      case GL_STENCIL_INDEX:
         return PIPE_MASK_S;
      default:
         assert(0);
         return 0;
      }

   case GL_DEPTH_COMPONENT:
      switch (srcFormat) {
      case GL_DEPTH_STENCIL:
      case GL_DEPTH_COMPONENT:
         return PIPE_MASK_Z;
      default:
         assert(0);
         return 0;
      }

   case GL_STENCIL_INDEX:
      switch (srcFormat) {
      case GL_STENCIL_INDEX:
         return PIPE_MASK_S;
      default:
         assert(0);
         return 0;
      }

   default:
      return PIPE_MASK_RGBA;
   }
}

/**
 * Converts format to a format with the same components, types
 * and sizes, but with the components in RGBA order.
 */
static enum pipe_format
unswizzle_format(enum pipe_format format)
{
   switch (format)
   {
   case PIPE_FORMAT_B8G8R8A8_UNORM:
   case PIPE_FORMAT_A8R8G8B8_UNORM:
   case PIPE_FORMAT_A8B8G8R8_UNORM:
      return PIPE_FORMAT_R8G8B8A8_UNORM;

   case PIPE_FORMAT_B10G10R10A2_UNORM:
      return PIPE_FORMAT_R10G10B10A2_UNORM;

   case PIPE_FORMAT_B10G10R10A2_SNORM:
      return PIPE_FORMAT_R10G10B10A2_SNORM;

   case PIPE_FORMAT_B10G10R10A2_UINT:
      return PIPE_FORMAT_R10G10B10A2_UINT;

   default:
      return format;
   }
}

/**
 * Converts PIPE_FORMAT_A* to PIPE_FORMAT_R*.
 */
static enum pipe_format
alpha_to_red(enum pipe_format format)
{
   switch (format)
   {
   case PIPE_FORMAT_A8_UNORM:
      return PIPE_FORMAT_R8_UNORM;
   case PIPE_FORMAT_A8_SNORM:
      return PIPE_FORMAT_R8_SNORM;
   case PIPE_FORMAT_A8_UINT:
      return PIPE_FORMAT_R8_UINT;
   case PIPE_FORMAT_A8_SINT:
      return PIPE_FORMAT_R8_SINT;

   case PIPE_FORMAT_A16_UNORM:
      return PIPE_FORMAT_R16_UNORM;
   case PIPE_FORMAT_A16_SNORM:
      return PIPE_FORMAT_R16_SNORM;
   case PIPE_FORMAT_A16_UINT:
      return PIPE_FORMAT_R16_UINT;
   case PIPE_FORMAT_A16_SINT:
      return PIPE_FORMAT_R16_SINT;
   case PIPE_FORMAT_A16_FLOAT:
      return PIPE_FORMAT_R16_FLOAT;

   case PIPE_FORMAT_A32_UINT:
      return PIPE_FORMAT_R32_UINT;
   case PIPE_FORMAT_A32_SINT:
      return PIPE_FORMAT_R32_SINT;
   case PIPE_FORMAT_A32_FLOAT:
      return PIPE_FORMAT_R32_FLOAT;

   default:
      return format;
   }
}

/**
 * Converts PIPE_FORMAT_R*A* to PIPE_FORMAT_R*G*.
 */
static enum pipe_format
red_alpha_to_red_green(enum pipe_format format)
{
   switch (format)
   {
   case PIPE_FORMAT_R8A8_UNORM:
      return PIPE_FORMAT_R8G8_UNORM;
   case PIPE_FORMAT_R8A8_SNORM:
      return PIPE_FORMAT_R8G8_SNORM;
   case PIPE_FORMAT_R8A8_UINT:
      return PIPE_FORMAT_R8G8_UINT;
   case PIPE_FORMAT_R8A8_SINT:
      return PIPE_FORMAT_R8G8_SINT;

   case PIPE_FORMAT_R16A16_UNORM:
      return PIPE_FORMAT_R16G16_UNORM;
   case PIPE_FORMAT_R16A16_SNORM:
      return PIPE_FORMAT_R16G16_SNORM;
   case PIPE_FORMAT_R16A16_UINT:
      return PIPE_FORMAT_R16G16_UINT;
   case PIPE_FORMAT_R16A16_SINT:
      return PIPE_FORMAT_R16G16_SINT;
   case PIPE_FORMAT_R16A16_FLOAT:
      return PIPE_FORMAT_R16G16_FLOAT;

   case PIPE_FORMAT_R32A32_UINT:
      return PIPE_FORMAT_R32G32_UINT;
   case PIPE_FORMAT_R32A32_SINT:
      return PIPE_FORMAT_R32G32_SINT;
   case PIPE_FORMAT_R32A32_FLOAT:
      return PIPE_FORMAT_R32G32_FLOAT;

   default:
       return format;
   }
}

/**
 * Converts PIPE_FORMAT_L*A* to PIPE_FORMAT_R*G*.
 */
static enum pipe_format
luminance_alpha_to_red_green(enum pipe_format format)
{
   switch (format)
   {
   case PIPE_FORMAT_L8A8_UNORM:
      return PIPE_FORMAT_R8G8_UNORM;
   case PIPE_FORMAT_L8A8_SNORM:
      return PIPE_FORMAT_R8G8_SNORM;
   case PIPE_FORMAT_L8A8_UINT:
      return PIPE_FORMAT_R8G8_UINT;
   case PIPE_FORMAT_L8A8_SINT:
      return PIPE_FORMAT_R8G8_SINT;

   case PIPE_FORMAT_L16A16_UNORM:
      return PIPE_FORMAT_R16G16_UNORM;
   case PIPE_FORMAT_L16A16_SNORM:
      return PIPE_FORMAT_R16G16_SNORM;
   case PIPE_FORMAT_L16A16_UINT:
      return PIPE_FORMAT_R16G16_UINT;
   case PIPE_FORMAT_L16A16_SINT:
      return PIPE_FORMAT_R16G16_SINT;
   case PIPE_FORMAT_L16A16_FLOAT:
      return PIPE_FORMAT_R16G16_FLOAT;

   case PIPE_FORMAT_L32A32_UINT:
      return PIPE_FORMAT_R32G32_UINT;
   case PIPE_FORMAT_L32A32_SINT:
      return PIPE_FORMAT_R32G32_SINT;
   case PIPE_FORMAT_L32A32_FLOAT:
      return PIPE_FORMAT_R32G32_FLOAT;

   default:
       return format;
   }
}

/**
 * Returns true if format is a PIPE_FORMAT_A* format, and false otherwise.
 */
static bool
format_is_alpha(enum pipe_format format)
{
   const struct util_format_description *desc = util_format_description(format);

   if (desc->nr_channels == 1 &&
       desc->swizzle[0] == PIPE_SWIZZLE_0 &&
       desc->swizzle[1] == PIPE_SWIZZLE_0 &&
       desc->swizzle[2] == PIPE_SWIZZLE_0 &&
       desc->swizzle[3] == PIPE_SWIZZLE_X)
      return true;

   return false;
}

/**
 * Returns true if format is a PIPE_FORMAT_R* format, and false otherwise.
 */
static bool
format_is_red(enum pipe_format format)
{
   const struct util_format_description *desc = util_format_description(format);

   if (desc->nr_channels == 1 &&
       desc->swizzle[0] == PIPE_SWIZZLE_X &&
       desc->swizzle[1] == PIPE_SWIZZLE_0 &&
       desc->swizzle[2] == PIPE_SWIZZLE_0 &&
       desc->swizzle[3] == PIPE_SWIZZLE_1)
      return true;

   return false;
}


/**
 * Returns true if format is a PIPE_FORMAT_L* format, and false otherwise.
 */
static bool
format_is_luminance(enum pipe_format format)
{
   const struct util_format_description *desc = util_format_description(format);

   if (desc->nr_channels == 1 &&
       desc->swizzle[0] == PIPE_SWIZZLE_X &&
       desc->swizzle[1] == PIPE_SWIZZLE_X &&
       desc->swizzle[2] == PIPE_SWIZZLE_X &&
       desc->swizzle[3] == PIPE_SWIZZLE_1)
      return true;

   return false;
}

/**
 * Returns true if format is a PIPE_FORMAT_R*A* format, and false otherwise.
 */
static bool
format_is_red_alpha(enum pipe_format format)
{
   const struct util_format_description *desc = util_format_description(format);

   if (desc->nr_channels == 2 &&
       desc->swizzle[0] == PIPE_SWIZZLE_X &&
       desc->swizzle[1] == PIPE_SWIZZLE_0 &&
       desc->swizzle[2] == PIPE_SWIZZLE_0 &&
       desc->swizzle[3] == PIPE_SWIZZLE_Y)
      return true;

   return false;
}

static bool
format_is_swizzled_rgba(enum pipe_format format)
{
    const struct util_format_description *desc = util_format_description(format);

    if ((desc->swizzle[0] == TGSI_SWIZZLE_X || desc->swizzle[0] == PIPE_SWIZZLE_0) &&
        (desc->swizzle[1] == TGSI_SWIZZLE_Y || desc->swizzle[1] == PIPE_SWIZZLE_0) &&
        (desc->swizzle[2] == TGSI_SWIZZLE_Z || desc->swizzle[2] == PIPE_SWIZZLE_0) &&
        (desc->swizzle[3] == TGSI_SWIZZLE_W || desc->swizzle[3] == PIPE_SWIZZLE_1))
       return false;

    return true;
}

struct format_table
{
   unsigned char swizzle[4];
   enum pipe_format format;
};

static const struct format_table table_8888_unorm[] = {
   { { 0, 1, 2, 3 }, PIPE_FORMAT_R8G8B8A8_UNORM },
   { { 2, 1, 0, 3 }, PIPE_FORMAT_B8G8R8A8_UNORM },
   { { 3, 0, 1, 2 }, PIPE_FORMAT_A8R8G8B8_UNORM },
   { { 3, 2, 1, 0 }, PIPE_FORMAT_A8B8G8R8_UNORM }
};

static const struct format_table table_1010102_unorm[] = {
   { { 0, 1, 2, 3 }, PIPE_FORMAT_R10G10B10A2_UNORM },
   { { 2, 1, 0, 3 }, PIPE_FORMAT_B10G10R10A2_UNORM }
};

static const struct format_table table_1010102_snorm[] = {
   { { 0, 1, 2, 3 }, PIPE_FORMAT_R10G10B10A2_SNORM },
   { { 2, 1, 0, 3 }, PIPE_FORMAT_B10G10R10A2_SNORM }
};

static const struct format_table table_1010102_uint[] = {
   { { 0, 1, 2, 3 }, PIPE_FORMAT_R10G10B10A2_UINT },
   { { 2, 1, 0, 3 }, PIPE_FORMAT_B10G10R10A2_UINT }
};

static enum pipe_format
swizzle_format(enum pipe_format format, const int * const swizzle)
{
   unsigned i;

   switch (format) {
   case PIPE_FORMAT_R8G8B8A8_UNORM:
   case PIPE_FORMAT_B8G8R8A8_UNORM:
   case PIPE_FORMAT_A8R8G8B8_UNORM:
   case PIPE_FORMAT_A8B8G8R8_UNORM:
      for (i = 0; i < ARRAY_SIZE(table_8888_unorm); i++) {
         if (swizzle[0] == table_8888_unorm[i].swizzle[0] &&
             swizzle[1] == table_8888_unorm[i].swizzle[1] &&
             swizzle[2] == table_8888_unorm[i].swizzle[2] &&
             swizzle[3] == table_8888_unorm[i].swizzle[3])
            return table_8888_unorm[i].format;
      }
      break;

   case PIPE_FORMAT_R10G10B10A2_UNORM:
   case PIPE_FORMAT_B10G10R10A2_UNORM:
      for (i = 0; i < ARRAY_SIZE(table_1010102_unorm); i++) {
         if (swizzle[0] == table_1010102_unorm[i].swizzle[0] &&
             swizzle[1] == table_1010102_unorm[i].swizzle[1] &&
             swizzle[2] == table_1010102_unorm[i].swizzle[2] &&
             swizzle[3] == table_1010102_unorm[i].swizzle[3])
            return table_1010102_unorm[i].format;
      }
      break;

   case PIPE_FORMAT_R10G10B10A2_SNORM:
   case PIPE_FORMAT_B10G10R10A2_SNORM:
      for (i = 0; i < ARRAY_SIZE(table_1010102_snorm); i++) {
         if (swizzle[0] == table_1010102_snorm[i].swizzle[0] &&
             swizzle[1] == table_1010102_snorm[i].swizzle[1] &&
             swizzle[2] == table_1010102_snorm[i].swizzle[2] &&
             swizzle[3] == table_1010102_snorm[i].swizzle[3])
            return table_1010102_snorm[i].format;
      }
      break;

   case PIPE_FORMAT_R10G10B10A2_UINT:
   case PIPE_FORMAT_B10G10R10A2_UINT:
      for (i = 0; i < ARRAY_SIZE(table_1010102_uint); i++) {
         if (swizzle[0] == table_1010102_uint[i].swizzle[0] &&
             swizzle[1] == table_1010102_uint[i].swizzle[1] &&
             swizzle[2] == table_1010102_uint[i].swizzle[2] &&
             swizzle[3] == table_1010102_uint[i].swizzle[3])
            return table_1010102_uint[i].format;
      }
      break;

   default:
      break;
   }

   return PIPE_FORMAT_NONE;
}

static bool
reinterpret_formats(enum pipe_format *src_format, enum pipe_format *dst_format)
{
   enum pipe_format src = *src_format;
   enum pipe_format dst = *dst_format;

   /* Note: dst_format has already been transformed from luminance/intensity
    *       to red when this function is called.  The source format will never
    *       be an intensity format, because GL_INTENSITY is not a legal value
    *       for the format parameter in glTex(Sub)Image(). */

   if (format_is_alpha(src)) {
      if (!format_is_alpha(dst))
         return false;

      src = alpha_to_red(src);
      dst = alpha_to_red(dst);
   } else if (format_is_luminance(src)) {
      if (!format_is_red(dst) && !format_is_red_alpha(dst))
         return false;

      src = util_format_luminance_to_red(src);
   } else if (util_format_is_luminance_alpha(src)) {
      src = luminance_alpha_to_red_green(src);

      if (format_is_red_alpha(dst)) {
         dst = red_alpha_to_red_green(dst);
      } else if (!format_is_red(dst))
         return false;
   } else if (format_is_swizzled_rgba(src)) {
      const struct util_format_description *src_desc = util_format_description(src);
      const struct util_format_description *dst_desc = util_format_description(dst);
      int swizzle[4];
      unsigned i;

      /* Make sure the format is an RGBA and not an RGBX format */
      if (src_desc->nr_channels != 4 || src_desc->swizzle[3] == PIPE_SWIZZLE_1)
         return false;

      if (dst_desc->nr_channels != 4 || dst_desc->swizzle[3] == PIPE_SWIZZLE_1)
         return false;

      for (i = 0; i < 4; i++)
         swizzle[i] = dst_desc->swizzle[src_desc->swizzle[i]];

      dst = swizzle_format(dst, swizzle);
      if (dst == PIPE_FORMAT_NONE)
         return false;

      src = unswizzle_format(src);
   }

   *src_format = src;
   *dst_format = dst;
   return true;
}

static bool
try_pbo_upload_common(struct gl_context *ctx,
                      struct pipe_surface *surface,
                      const struct st_pbo_addresses *addr,
                      enum pipe_format src_format)
{
   struct st_context *st = st_context(ctx);
   struct cso_context *cso = st->cso_context;
   struct pipe_context *pipe = st->pipe;
   bool success = false;
   void *fs;

   fs = st_pbo_get_upload_fs(st, src_format, surface->format);
   if (!fs)
      return false;

   cso_save_state(cso, (CSO_BIT_FRAGMENT_SAMPLER_VIEWS |
                        CSO_BIT_FRAGMENT_SAMPLERS |
                        CSO_BIT_VERTEX_ELEMENTS |
                        CSO_BIT_AUX_VERTEX_BUFFER_SLOT |
                        CSO_BIT_FRAMEBUFFER |
                        CSO_BIT_VIEWPORT |
                        CSO_BIT_BLEND |
                        CSO_BIT_DEPTH_STENCIL_ALPHA |
                        CSO_BIT_RASTERIZER |
                        CSO_BIT_STREAM_OUTPUTS |
                        CSO_BIT_PAUSE_QUERIES |
                        CSO_BIT_SAMPLE_MASK |
                        CSO_BIT_MIN_SAMPLES |
                        CSO_BIT_RENDER_CONDITION |
                        CSO_BITS_ALL_SHADERS));
   cso_save_constant_buffer_slot0(cso, PIPE_SHADER_FRAGMENT);

   cso_set_sample_mask(cso, ~0);
   cso_set_min_samples(cso, 1);
   cso_set_render_condition(cso, NULL, FALSE, 0);

   /* Set up the sampler_view */
   {
      struct pipe_sampler_view templ;
      struct pipe_sampler_view *sampler_view;
      struct pipe_sampler_state sampler = {0};
      const struct pipe_sampler_state *samplers[1] = {&sampler};

      memset(&templ, 0, sizeof(templ));
      templ.target = PIPE_BUFFER;
      templ.format = src_format;
      templ.u.buf.offset = addr->first_element * addr->bytes_per_pixel;
      templ.u.buf.size = (addr->last_element - addr->first_element + 1) *
                         addr->bytes_per_pixel;
      templ.swizzle_r = PIPE_SWIZZLE_X;
      templ.swizzle_g = PIPE_SWIZZLE_Y;
      templ.swizzle_b = PIPE_SWIZZLE_Z;
      templ.swizzle_a = PIPE_SWIZZLE_W;

      sampler_view = pipe->create_sampler_view(pipe, addr->buffer, &templ);
      if (sampler_view == NULL)
         goto fail;

      cso_set_sampler_views(cso, PIPE_SHADER_FRAGMENT, 1, &sampler_view);

      pipe_sampler_view_reference(&sampler_view, NULL);

      cso_set_samplers(cso, PIPE_SHADER_FRAGMENT, 1, samplers);
   }

   /* Framebuffer_state */
   {
      struct pipe_framebuffer_state fb;
      memset(&fb, 0, sizeof(fb));
      fb.width = surface->width;
      fb.height = surface->height;
      fb.nr_cbufs = 1;
      pipe_surface_reference(&fb.cbufs[0], surface);

      cso_set_framebuffer(cso, &fb);

      pipe_surface_reference(&fb.cbufs[0], NULL);
   }

   cso_set_viewport_dims(cso, surface->width, surface->height, FALSE);

   /* Blend state */
   cso_set_blend(cso, &st->pbo.upload_blend);

   /* Depth/stencil/alpha state */
   {
      struct pipe_depth_stencil_alpha_state dsa;
      memset(&dsa, 0, sizeof(dsa));
      cso_set_depth_stencil_alpha(cso, &dsa);
   }

   /* Set up the fragment shader */
   cso_set_fragment_shader_handle(cso, fs);

   success = st_pbo_draw(st, addr, surface->width, surface->height);

fail:
   cso_restore_state(cso);
   cso_restore_constant_buffer_slot0(cso, PIPE_SHADER_FRAGMENT);

   return success;
}

static bool
try_pbo_upload(struct gl_context *ctx, GLuint dims,
               struct gl_texture_image *texImage,
               GLenum format, GLenum type,
               enum pipe_format dst_format,
               GLint xoffset, GLint yoffset, GLint zoffset,
               GLint width, GLint height, GLint depth,
               const void *pixels,
               const struct gl_pixelstore_attrib *unpack)
{
   struct st_context *st = st_context(ctx);
   struct st_texture_image *stImage = st_texture_image(texImage);
   struct st_texture_object *stObj = st_texture_object(texImage->TexObject);
   struct pipe_resource *texture = stImage->pt;
   struct pipe_context *pipe = st->pipe;
   struct pipe_screen *screen = pipe->screen;
   struct pipe_surface *surface = NULL;
   struct st_pbo_addresses addr;
   enum pipe_format src_format;
   const struct util_format_description *desc;
   GLenum gl_target = texImage->TexObject->Target;
   bool success;

   if (!st->pbo.upload_enabled)
      return false;

   /* From now on, we need the gallium representation of dimensions. */
   if (gl_target == GL_TEXTURE_1D_ARRAY) {
      depth = height;
      height = 1;
      zoffset = yoffset;
      yoffset = 0;
   }

   if (depth != 1 && !st->pbo.layers)
      return false;

   /* Choose the source format. Initially, we do so without checking driver
    * support at all because of the remapping we later perform and because
    * at least the Radeon driver actually supports some formats for texture
    * buffers which it doesn't support for regular textures. */
   src_format = st_choose_matching_format(st, 0, format, type, unpack->SwapBytes);
   if (!src_format) {
      return false;
   }

   src_format = util_format_linear(src_format);
   desc = util_format_description(src_format);

   if (desc->layout != UTIL_FORMAT_LAYOUT_PLAIN)
      return false;

   if (desc->colorspace != UTIL_FORMAT_COLORSPACE_RGB)
      return false;

   if (st->pbo.rgba_only) {
      enum pipe_format orig_dst_format = dst_format;

      if (!reinterpret_formats(&src_format, &dst_format)) {
         return false;
      }

      if (dst_format != orig_dst_format &&
          !screen->is_format_supported(screen, dst_format, PIPE_TEXTURE_2D, 0,
                                       PIPE_BIND_RENDER_TARGET)) {
         return false;
      }
   }

   if (!src_format ||
       !screen->is_format_supported(screen, src_format, PIPE_BUFFER, 0,
                                    PIPE_BIND_SAMPLER_VIEW)) {
      return false;
   }

   /* Compute buffer addresses */
   addr.xoffset = xoffset;
   addr.yoffset = yoffset;
   addr.width = width;
   addr.height = height;
   addr.depth = depth;
   addr.bytes_per_pixel = desc->block.bits / 8;

   if (!st_pbo_addresses_pixelstore(st, gl_target, dims == 3, unpack, pixels,
                                    &addr))
      return false;

   /* Set up the surface */
   {
      unsigned level = stObj->pt != stImage->pt ? 0 : texImage->TexObject->MinLevel + texImage->Level;
      unsigned max_layer = util_max_layer(texture, level);

      zoffset += texImage->Face + texImage->TexObject->MinLayer;

      struct pipe_surface templ;
      memset(&templ, 0, sizeof(templ));
      templ.format = dst_format;
      templ.u.tex.level = level;
      templ.u.tex.first_layer = MIN2(zoffset, max_layer);
      templ.u.tex.last_layer = MIN2(zoffset + depth - 1, max_layer);

      surface = pipe->create_surface(pipe, texture, &templ);
      if (!surface)
         return false;
   }

   success = try_pbo_upload_common(ctx, surface, &addr, src_format);

   pipe_surface_reference(&surface, NULL);

   return success;
}

static void
st_TexSubImage(struct gl_context *ctx, GLuint dims,
               struct gl_texture_image *texImage,
               GLint xoffset, GLint yoffset, GLint zoffset,
               GLint width, GLint height, GLint depth,
               GLenum format, GLenum type, const void *pixels,
               const struct gl_pixelstore_attrib *unpack)
{
   struct st_context *st = st_context(ctx);
   struct st_texture_image *stImage = st_texture_image(texImage);
   struct st_texture_object *stObj = st_texture_object(texImage->TexObject);
   struct pipe_context *pipe = st->pipe;
   struct pipe_screen *screen = pipe->screen;
   struct pipe_resource *dst = stImage->pt;
   struct pipe_resource *src = NULL;
   struct pipe_resource src_templ;
   struct pipe_transfer *transfer;
   struct pipe_blit_info blit;
   enum pipe_format src_format, dst_format;
   mesa_format mesa_src_format;
   GLenum gl_target = texImage->TexObject->Target;
   unsigned bind;
   GLubyte *map;
   unsigned dstz = texImage->Face + texImage->TexObject->MinLayer;
   unsigned dst_level = 0;

   st_flush_bitmap_cache(st);
   st_invalidate_readpix_cache(st);

   if (stObj->pt == stImage->pt)
      dst_level = texImage->TexObject->MinLevel + texImage->Level;

   assert(!_mesa_is_format_etc2(texImage->TexFormat) &&
          !_mesa_is_format_astc_2d(texImage->TexFormat) &&
          texImage->TexFormat != MESA_FORMAT_ETC1_RGB8);

   if (!dst)
      goto fallback;

   /* Try texture_subdata, which should be the fastest memcpy path. */
   if (pixels &&
       !_mesa_is_bufferobj(unpack->BufferObj) &&
       _mesa_texstore_can_use_memcpy(ctx, texImage->_BaseFormat,
                                     texImage->TexFormat, format, type,
                                     unpack)) {
      struct pipe_box box;
      unsigned stride, layer_stride;
      void *data;

      stride = _mesa_image_row_stride(unpack, width, format, type);
      layer_stride = _mesa_image_image_stride(unpack, width, height, format,
                                              type);
      data = _mesa_image_address(dims, unpack, pixels, width, height, format,
                                 type, 0, 0, 0);

      /* Convert to Gallium coordinates. */
      if (gl_target == GL_TEXTURE_1D_ARRAY) {
         zoffset = yoffset;
         yoffset = 0;
         depth = height;
         height = 1;
         layer_stride = stride;
      }

      u_box_3d(xoffset, yoffset, zoffset + dstz, width, height, depth, &box);
      pipe->texture_subdata(pipe, dst, dst_level, 0,
                            &box, data, stride, layer_stride);
      return;
   }

   if (!st->prefer_blit_based_texture_transfer) {
      goto fallback;
   }

   /* XXX Fallback for depth-stencil formats due to an incomplete stencil
    * blit implementation in some drivers. */
   if (format == GL_DEPTH_STENCIL) {
      goto fallback;
   }

   /* If the base internal format and the texture format don't match,
    * we can't use blit-based TexSubImage. */
   if (texImage->_BaseFormat !=
       _mesa_get_format_base_format(texImage->TexFormat)) {
      goto fallback;
   }


   /* See if the destination format is supported. */
   if (format == GL_DEPTH_COMPONENT || format == GL_DEPTH_STENCIL)
      bind = PIPE_BIND_DEPTH_STENCIL;
   else
      bind = PIPE_BIND_RENDER_TARGET;

   /* For luminance and intensity, only the red channel is stored
    * in the destination. */
   dst_format = util_format_linear(dst->format);
   dst_format = util_format_luminance_to_red(dst_format);
   dst_format = util_format_intensity_to_red(dst_format);

   if (!dst_format ||
       !screen->is_format_supported(screen, dst_format, dst->target,
                                    dst->nr_samples, bind)) {
      goto fallback;
   }

   if (_mesa_is_bufferobj(unpack->BufferObj)) {
      if (try_pbo_upload(ctx, dims, texImage, format, type, dst_format,
                         xoffset, yoffset, zoffset,
                         width, height, depth, pixels, unpack))
         return;
   }

   /* See if the texture format already matches the format and type,
    * in which case the memcpy-based fast path will likely be used and
    * we don't have to blit. */
   if (_mesa_format_matches_format_and_type(texImage->TexFormat, format,
                                            type, unpack->SwapBytes, NULL)) {
      goto fallback;
   }

   /* Choose the source format. */
   src_format = st_choose_matching_format(st, PIPE_BIND_SAMPLER_VIEW,
                                          format, type, unpack->SwapBytes);
   if (!src_format) {
      goto fallback;
   }

   mesa_src_format = st_pipe_format_to_mesa_format(src_format);

   /* There is no reason to do this if we cannot use memcpy for the temporary
    * source texture at least. This also takes transfer ops into account,
    * etc. */
   if (!_mesa_texstore_can_use_memcpy(ctx,
                             _mesa_get_format_base_format(mesa_src_format),
                             mesa_src_format, format, type, unpack)) {
      goto fallback;
   }

   /* TexSubImage only sets a single cubemap face. */
   if (gl_target == GL_TEXTURE_CUBE_MAP) {
      gl_target = GL_TEXTURE_2D;
   }
   /* TexSubImage can specify subsets of cube map array faces
    * so we need to upload via 2D array instead */
   if (gl_target == GL_TEXTURE_CUBE_MAP_ARRAY) {
      gl_target = GL_TEXTURE_2D_ARRAY;
   }

   /* Initialize the source texture description. */
   memset(&src_templ, 0, sizeof(src_templ));
   src_templ.target = gl_target_to_pipe(gl_target);
   src_templ.format = src_format;
   src_templ.bind = PIPE_BIND_SAMPLER_VIEW;
   src_templ.usage = PIPE_USAGE_STAGING;

   st_gl_texture_dims_to_pipe_dims(gl_target, width, height, depth,
                                   &src_templ.width0, &src_templ.height0,
                                   &src_templ.depth0, &src_templ.array_size);

   /* Check for NPOT texture support. */
   if (!screen->get_param(screen, PIPE_CAP_NPOT_TEXTURES) &&
       (!util_is_power_of_two_or_zero(src_templ.width0) ||
        !util_is_power_of_two_or_zero(src_templ.height0) ||
        !util_is_power_of_two_or_zero(src_templ.depth0))) {
      goto fallback;
   }

   /* Create the source texture. */
   src = screen->resource_create(screen, &src_templ);
   if (!src) {
      goto fallback;
   }

   /* Map source pixels. */
   pixels = _mesa_validate_pbo_teximage(ctx, dims, width, height, depth,
                                        format, type, pixels, unpack,
                                        "glTexSubImage");
   if (!pixels) {
      /* This is a GL error. */
      pipe_resource_reference(&src, NULL);
      return;
   }

   /* From now on, we need the gallium representation of dimensions. */
   if (gl_target == GL_TEXTURE_1D_ARRAY) {
      zoffset = yoffset;
      yoffset = 0;
      depth = height;
      height = 1;
   }

   map = pipe_transfer_map_3d(pipe, src, 0, PIPE_TRANSFER_WRITE, 0, 0, 0,
                              width, height, depth, &transfer);
   if (!map) {
      _mesa_unmap_teximage_pbo(ctx, unpack);
      pipe_resource_reference(&src, NULL);
      goto fallback;
   }

   /* Upload pixels (just memcpy). */
   {
      const uint bytesPerRow = width * util_format_get_blocksize(src_format);
      GLuint row, slice;

      for (slice = 0; slice < (unsigned) depth; slice++) {
         if (gl_target == GL_TEXTURE_1D_ARRAY) {
            /* 1D array textures.
             * We need to convert gallium coords to GL coords.
             */
            void *src = _mesa_image_address2d(unpack, pixels,
                                                width, depth, format,
                                                type, slice, 0);
            memcpy(map, src, bytesPerRow);
         }
         else {
            ubyte *slice_map = map;

            for (row = 0; row < (unsigned) height; row++) {
               void *src = _mesa_image_address(dims, unpack, pixels,
                                                 width, height, format,
                                                 type, slice, row, 0);
               memcpy(slice_map, src, bytesPerRow);
               slice_map += transfer->stride;
            }
         }
         map += transfer->layer_stride;
      }
   }

   pipe_transfer_unmap(pipe, transfer);
   _mesa_unmap_teximage_pbo(ctx, unpack);

   /* Blit. */
   memset(&blit, 0, sizeof(blit));
   blit.src.resource = src;
   blit.src.level = 0;
   blit.src.format = src_format;
   blit.dst.resource = dst;
   blit.dst.level = dst_level;
   blit.dst.format = dst_format;
   blit.src.box.x = blit.src.box.y = blit.src.box.z = 0;
   blit.dst.box.x = xoffset;
   blit.dst.box.y = yoffset;
   blit.dst.box.z = zoffset + dstz;
   blit.src.box.width = blit.dst.box.width = width;
   blit.src.box.height = blit.dst.box.height = height;
   blit.src.box.depth = blit.dst.box.depth = depth;
   blit.mask = st_get_blit_mask(format, texImage->_BaseFormat);
   blit.filter = PIPE_TEX_FILTER_NEAREST;
   blit.scissor_enable = FALSE;

   st->pipe->blit(st->pipe, &blit);

   pipe_resource_reference(&src, NULL);
   return;

fallback:
   _mesa_store_texsubimage(ctx, dims, texImage, xoffset, yoffset, zoffset,
                           width, height, depth, format, type, pixels,
                           unpack);
}

static void
st_TexImage(struct gl_context * ctx, GLuint dims,
            struct gl_texture_image *texImage,
            GLenum format, GLenum type, const void *pixels,
            const struct gl_pixelstore_attrib *unpack)
{
   assert(dims == 1 || dims == 2 || dims == 3);

   prep_teximage(ctx, texImage, format, type);

   if (texImage->Width == 0 || texImage->Height == 0 || texImage->Depth == 0)
      return;

   /* allocate storage for texture data */
   if (!ctx->Driver.AllocTextureImageBuffer(ctx, texImage)) {
      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glTexImage%uD", dims);
      return;
   }

   st_TexSubImage(ctx, dims, texImage, 0, 0, 0,
                  texImage->Width, texImage->Height, texImage->Depth,
                  format, type, pixels, unpack);
}


static void
st_CompressedTexSubImage(struct gl_context *ctx, GLuint dims,
                         struct gl_texture_image *texImage,
                         GLint x, GLint y, GLint z,
                         GLsizei w, GLsizei h, GLsizei d,
                         GLenum format, GLsizei imageSize, const void *data)
{
   struct st_context *st = st_context(ctx);
   struct st_texture_image *stImage = st_texture_image(texImage);
   struct st_texture_object *stObj = st_texture_object(texImage->TexObject);
   struct pipe_resource *texture = stImage->pt;
   struct pipe_context *pipe = st->pipe;
   struct pipe_screen *screen = pipe->screen;
   struct pipe_resource *dst = stImage->pt;
   struct pipe_surface *surface = NULL;
   struct compressed_pixelstore store;
   struct st_pbo_addresses addr;
   enum pipe_format copy_format;
   unsigned bw, bh;
   intptr_t buf_offset;
   bool success = false;

   /* Check basic pre-conditions for PBO upload */
   if (!st->prefer_blit_based_texture_transfer) {
      goto fallback;
   }

   if (!_mesa_is_bufferobj(ctx->Unpack.BufferObj))
      goto fallback;

   if (st_compressed_format_fallback(st, texImage->TexFormat))
      goto fallback;

   if (!dst) {
      goto fallback;
   }

   if (!st->pbo.upload_enabled ||
       !screen->get_param(screen, PIPE_CAP_SURFACE_REINTERPRET_BLOCKS)) {
      goto fallback;
   }

   /* Choose the pipe format for the upload. */
   addr.bytes_per_pixel = util_format_get_blocksize(dst->format);
   bw = util_format_get_blockwidth(dst->format);
   bh = util_format_get_blockheight(dst->format);

   switch (addr.bytes_per_pixel) {
   case 8:
      copy_format = PIPE_FORMAT_R16G16B16A16_UINT;
      break;
   case 16:
      copy_format = PIPE_FORMAT_R32G32B32A32_UINT;
      break;
   default:
      goto fallback;
   }

   if (!screen->is_format_supported(screen, copy_format, PIPE_BUFFER, 0,
                                    PIPE_BIND_SAMPLER_VIEW)) {
      goto fallback;
   }

   if (!screen->is_format_supported(screen, copy_format, dst->target,
                                    dst->nr_samples, PIPE_BIND_RENDER_TARGET)) {
      goto fallback;
   }

   /* Interpret the pixelstore settings. */
   _mesa_compute_compressed_pixelstore(dims, texImage->TexFormat, w, h, d,
                                       &ctx->Unpack, &store);
   assert(store.CopyBytesPerRow % addr.bytes_per_pixel == 0);
   assert(store.SkipBytes % addr.bytes_per_pixel == 0);

   /* Compute the offset into the buffer */
   buf_offset = (intptr_t)data + store.SkipBytes;

   if (buf_offset % addr.bytes_per_pixel) {
      goto fallback;
   }

   buf_offset = buf_offset / addr.bytes_per_pixel;

   addr.xoffset = x / bw;
   addr.yoffset = y / bh;
   addr.width = store.CopyBytesPerRow / addr.bytes_per_pixel;
   addr.height = store.CopyRowsPerSlice;
   addr.depth = d;
   addr.pixels_per_row = store.TotalBytesPerRow / addr.bytes_per_pixel;
   addr.image_height = store.TotalRowsPerSlice;

   if (!st_pbo_addresses_setup(st, st_buffer_object(ctx->Unpack.BufferObj)->buffer,
                               buf_offset, &addr))
      goto fallback;

   /* Set up the surface. */
   {
      unsigned level = stObj->pt != stImage->pt ? 0 : texImage->TexObject->MinLevel + texImage->Level;
      unsigned max_layer = util_max_layer(texture, level);

      z += texImage->Face + texImage->TexObject->MinLayer;

      struct pipe_surface templ;
      memset(&templ, 0, sizeof(templ));
      templ.format = copy_format;
      templ.u.tex.level = level;
      templ.u.tex.first_layer = MIN2(z, max_layer);
      templ.u.tex.last_layer = MIN2(z + d - 1, max_layer);

      surface = pipe->create_surface(pipe, texture, &templ);
      if (!surface)
         goto fallback;
   }

   success = try_pbo_upload_common(ctx, surface, &addr, copy_format);

   pipe_surface_reference(&surface, NULL);

   if (success)
      return;

fallback:
   _mesa_store_compressed_texsubimage(ctx, dims, texImage,
                                      x, y, z, w, h, d,
                                      format, imageSize, data);
}

static void
st_CompressedTexImage(struct gl_context *ctx, GLuint dims,
                      struct gl_texture_image *texImage,
                      GLsizei imageSize, const void *data)
{
   prep_teximage(ctx, texImage, GL_NONE, GL_NONE);

   /* only 2D and 3D compressed images are supported at this time */
   if (dims == 1) {
      _mesa_problem(ctx, "Unexpected glCompressedTexImage1D call");
      return;
   }

   /* This is pretty simple, because unlike the general texstore path we don't
    * have to worry about the usual image unpacking or image transfer
    * operations.
    */
   assert(texImage);
   assert(texImage->Width > 0);
   assert(texImage->Height > 0);
   assert(texImage->Depth > 0);

   /* allocate storage for texture data */
   if (!st_AllocTextureImageBuffer(ctx, texImage)) {
      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glCompressedTexImage%uD", dims);
      return;
   }

   st_CompressedTexSubImage(ctx, dims, texImage,
                            0, 0, 0,
                            texImage->Width, texImage->Height, texImage->Depth,
                            texImage->TexFormat,
                            imageSize, data);
}




/**
 * Called via ctx->Driver.GetTexSubImage()
 *
 * This uses a blit to copy the texture to a texture format which matches
 * the format and type combo and then a fast read-back is done using memcpy.
 * We can do arbitrary X/Y/Z/W/0/1 swizzling here as long as there is
 * a format which matches the swizzling.
 *
 * If such a format isn't available, it falls back to _mesa_GetTexImage_sw.
 *
 * NOTE: Drivers usually do a blit to convert between tiled and linear
 *       texture layouts during texture uploads/downloads, so the blit
 *       we do here should be free in such cases.
 */
static void
st_GetTexSubImage(struct gl_context * ctx,
                  GLint xoffset, GLint yoffset, GLint zoffset,
                  GLsizei width, GLsizei height, GLint depth,
                  GLenum format, GLenum type, void * pixels,
                  struct gl_texture_image *texImage)
{
   struct st_context *st = st_context(ctx);
   struct pipe_context *pipe = st->pipe;
   struct pipe_screen *screen = pipe->screen;
   struct st_texture_image *stImage = st_texture_image(texImage);
   struct st_texture_object *stObj = st_texture_object(texImage->TexObject);
   struct pipe_resource *src = stObj->pt;
   struct pipe_resource *dst = NULL;
   struct pipe_resource dst_templ;
   enum pipe_format dst_format, src_format;
   mesa_format mesa_format;
   GLenum gl_target = texImage->TexObject->Target;
   enum pipe_texture_target pipe_target;
   unsigned dims;
   struct pipe_blit_info blit;
   unsigned bind;
   struct pipe_transfer *tex_xfer;
   ubyte *map = NULL;
   boolean done = FALSE;

   assert(!_mesa_is_format_etc2(texImage->TexFormat) &&
          !_mesa_is_format_astc_2d(texImage->TexFormat) &&
          texImage->TexFormat != MESA_FORMAT_ETC1_RGB8);

   st_flush_bitmap_cache(st);

   if (!st->prefer_blit_based_texture_transfer &&
       !_mesa_is_format_compressed(texImage->TexFormat)) {
      /* Try to avoid the fallback if we're doing texture decompression here */
      goto fallback;
   }

   /* Handle non-finalized textures. */
   if (!stImage->pt || stImage->pt != stObj->pt || !src) {
      goto fallback;
   }

   /* XXX Fallback to _mesa_GetTexImage_sw for depth-stencil formats
    * due to an incomplete stencil blit implementation in some drivers. */
   if (format == GL_DEPTH_STENCIL || format == GL_STENCIL_INDEX) {
      goto fallback;
   }

   /* If the base internal format and the texture format don't match, we have
    * to fall back to _mesa_GetTexImage_sw. */
   if (texImage->_BaseFormat !=
       _mesa_get_format_base_format(texImage->TexFormat)) {
      goto fallback;
   }

   /* See if the texture format already matches the format and type,
    * in which case the memcpy-based fast path will be used. */
   if (_mesa_format_matches_format_and_type(texImage->TexFormat, format,
                                            type, ctx->Pack.SwapBytes, NULL)) {
      goto fallback;
   }

   /* Convert the source format to what is expected by GetTexImage
    * and see if it's supported.
    *
    * This only applies to glGetTexImage:
    * - Luminance must be returned as (L,0,0,1).
    * - Luminance alpha must be returned as (L,0,0,A).
    * - Intensity must be returned as (I,0,0,1)
    */
   if (stObj->surface_based)
      src_format = util_format_linear(stObj->surface_format);
   else
      src_format = util_format_linear(src->format);
   src_format = util_format_luminance_to_red(src_format);
   src_format = util_format_intensity_to_red(src_format);

   if (!src_format ||
       !screen->is_format_supported(screen, src_format, src->target,
                                    src->nr_samples,
                                    PIPE_BIND_SAMPLER_VIEW)) {
      goto fallback;
   }

   if (format == GL_DEPTH_COMPONENT || format == GL_DEPTH_STENCIL)
      bind = PIPE_BIND_DEPTH_STENCIL;
   else
      bind = PIPE_BIND_RENDER_TARGET;

   /* GetTexImage only returns a single face for cubemaps. */
   if (gl_target == GL_TEXTURE_CUBE_MAP) {
      gl_target = GL_TEXTURE_2D;
   }
   pipe_target = gl_target_to_pipe(gl_target);

   /* Choose the destination format by finding the best match
    * for the format+type combo. */
   dst_format = st_choose_matching_format(st, bind, format, type,
                                          ctx->Pack.SwapBytes);

   if (dst_format == PIPE_FORMAT_NONE) {
      GLenum dst_glformat;

      /* Fall back to _mesa_GetTexImage_sw except for compressed formats,
       * where decompression with a blit is always preferred. */
      if (!util_format_is_compressed(src->format)) {
         goto fallback;
      }

      /* Set the appropriate format for the decompressed texture.
       * Luminance and sRGB formats shouldn't appear here.*/
      switch (src_format) {
      case PIPE_FORMAT_DXT1_RGB:
      case PIPE_FORMAT_DXT1_RGBA:
      case PIPE_FORMAT_DXT3_RGBA:
      case PIPE_FORMAT_DXT5_RGBA:
      case PIPE_FORMAT_RGTC1_UNORM:
      case PIPE_FORMAT_RGTC2_UNORM:
      case PIPE_FORMAT_ETC1_RGB8:
      case PIPE_FORMAT_ETC2_RGB8:
      case PIPE_FORMAT_ETC2_RGB8A1:
      case PIPE_FORMAT_ETC2_RGBA8:
      case PIPE_FORMAT_ASTC_4x4:
      case PIPE_FORMAT_ASTC_5x4:
      case PIPE_FORMAT_ASTC_5x5:
      case PIPE_FORMAT_ASTC_6x5:
      case PIPE_FORMAT_ASTC_6x6:
      case PIPE_FORMAT_ASTC_8x5:
      case PIPE_FORMAT_ASTC_8x6:
      case PIPE_FORMAT_ASTC_8x8:
      case PIPE_FORMAT_ASTC_10x5:
      case PIPE_FORMAT_ASTC_10x6:
      case PIPE_FORMAT_ASTC_10x8:
      case PIPE_FORMAT_ASTC_10x10:
      case PIPE_FORMAT_ASTC_12x10:
      case PIPE_FORMAT_ASTC_12x12:
      case PIPE_FORMAT_BPTC_RGBA_UNORM:
         dst_glformat = GL_RGBA8;
         break;
      case PIPE_FORMAT_RGTC1_SNORM:
      case PIPE_FORMAT_RGTC2_SNORM:
         if (!ctx->Extensions.EXT_texture_snorm)
            goto fallback;
         dst_glformat = GL_RGBA8_SNORM;
         break;
      case PIPE_FORMAT_BPTC_RGB_FLOAT:
      case PIPE_FORMAT_BPTC_RGB_UFLOAT:
         if (!ctx->Extensions.ARB_texture_float)
            goto fallback;
         dst_glformat = GL_RGBA32F;
         break;
      case PIPE_FORMAT_ETC2_R11_UNORM:
         if (!screen->is_format_supported(screen, PIPE_FORMAT_R16_UNORM,
                                          pipe_target, 0, bind))
            goto fallback;
         dst_glformat = GL_R16;
         break;
      case PIPE_FORMAT_ETC2_R11_SNORM:
         if (!screen->is_format_supported(screen, PIPE_FORMAT_R16_SNORM,
                                          pipe_target, 0, bind))
            goto fallback;
         dst_glformat = GL_R16_SNORM;
         break;
      case PIPE_FORMAT_ETC2_RG11_UNORM:
         if (!screen->is_format_supported(screen, PIPE_FORMAT_R16G16_UNORM,
                                          pipe_target, 0, bind))
            goto fallback;
         dst_glformat = GL_RG16;
         break;
      case PIPE_FORMAT_ETC2_RG11_SNORM:
         if (!screen->is_format_supported(screen, PIPE_FORMAT_R16G16_SNORM,
                                          pipe_target, 0, bind))
            goto fallback;
         dst_glformat = GL_RG16_SNORM;
         break;
      default:
         assert(0);
         goto fallback;
      }

      dst_format = st_choose_format(st, dst_glformat, format, type,
                                    pipe_target, 0, bind, FALSE);

      if (dst_format == PIPE_FORMAT_NONE) {
         /* unable to get an rgba format!?! */
         goto fallback;
      }
   }

   /* create the destination texture of size (width X height X depth) */
   memset(&dst_templ, 0, sizeof(dst_templ));
   dst_templ.target = pipe_target;
   dst_templ.format = dst_format;
   dst_templ.bind = bind;
   dst_templ.usage = PIPE_USAGE_STAGING;

   st_gl_texture_dims_to_pipe_dims(gl_target, width, height, depth,
                                   &dst_templ.width0, &dst_templ.height0,
                                   &dst_templ.depth0, &dst_templ.array_size);

   dst = screen->resource_create(screen, &dst_templ);
   if (!dst) {
      goto fallback;
   }

   /* From now on, we need the gallium representation of dimensions. */
   if (gl_target == GL_TEXTURE_1D_ARRAY) {
      zoffset = yoffset;
      yoffset = 0;
      depth = height;
      height = 1;
   }

   assert(texImage->Face == 0 ||
          texImage->TexObject->MinLayer == 0 ||
          zoffset == 0);

   memset(&blit, 0, sizeof(blit));
   blit.src.resource = src;
   blit.src.level = texImage->Level + texImage->TexObject->MinLevel;
   blit.src.format = src_format;
   blit.dst.resource = dst;
   blit.dst.level = 0;
   blit.dst.format = dst->format;
   blit.src.box.x = xoffset;
   blit.dst.box.x = 0;
   blit.src.box.y = yoffset;
   blit.dst.box.y = 0;
   blit.src.box.z = texImage->Face + texImage->TexObject->MinLayer + zoffset;
   blit.dst.box.z = 0;
   blit.src.box.width = blit.dst.box.width = width;
   blit.src.box.height = blit.dst.box.height = height;
   blit.src.box.depth = blit.dst.box.depth = depth;
   blit.mask = st_get_blit_mask(texImage->_BaseFormat, format);
   blit.filter = PIPE_TEX_FILTER_NEAREST;
   blit.scissor_enable = FALSE;

   /* blit/render/decompress */
   st->pipe->blit(st->pipe, &blit);

   pixels = _mesa_map_pbo_dest(ctx, &ctx->Pack, pixels);

   map = pipe_transfer_map_3d(pipe, dst, 0, PIPE_TRANSFER_READ,
                              0, 0, 0, width, height, depth, &tex_xfer);
   if (!map) {
      goto end;
   }

   mesa_format = st_pipe_format_to_mesa_format(dst_format);
   dims = _mesa_get_texture_dimensions(gl_target);

   /* copy/pack data into user buffer */
   if (_mesa_format_matches_format_and_type(mesa_format, format, type,
                                            ctx->Pack.SwapBytes, NULL)) {
      /* memcpy */
      const uint bytesPerRow = width * util_format_get_blocksize(dst_format);
      GLuint row, slice;

      for (slice = 0; slice < depth; slice++) {
         ubyte *slice_map = map;

         for (row = 0; row < height; row++) {
            void *dest = _mesa_image_address(dims, &ctx->Pack, pixels,
                                             width, height, format, type,
                                             slice, row, 0);

            memcpy(dest, slice_map, bytesPerRow);

            slice_map += tex_xfer->stride;
         }

         map += tex_xfer->layer_stride;
      }
   }
   else {
      /* format translation via floats */
      GLuint slice;
      GLfloat *rgba;
      uint32_t dstMesaFormat;
      int dstStride, srcStride;

      assert(util_format_is_compressed(src->format));

      rgba = malloc(width * height * 4 * sizeof(GLfloat));
      if (!rgba) {
         goto end;
      }

      if (ST_DEBUG & DEBUG_FALLBACK)
         debug_printf("%s: fallback format translation\n", __func__);

      dstMesaFormat = _mesa_format_from_format_and_type(format, type);
      dstStride = _mesa_image_row_stride(&ctx->Pack, width, format, type);
      srcStride = 4 * width * sizeof(GLfloat);
      for (slice = 0; slice < depth; slice++) {
         void *dest = _mesa_image_address(dims, &ctx->Pack, pixels,
                                          width, height, format, type,
                                          slice, 0, 0);

         /* get float[4] rgba row from surface */
         pipe_get_tile_rgba_format(tex_xfer, map, 0, 0, width, height,
                                   dst_format, rgba);

         _mesa_format_convert(dest, dstMesaFormat, dstStride,
                              rgba, RGBA32_FLOAT, srcStride,
                              width, height, NULL);

         /* Handle byte swapping if required */
         if (ctx->Pack.SwapBytes) {
            _mesa_swap_bytes_2d_image(format, type, &ctx->Pack,
                                      width, height, dest, dest);
         }

         map += tex_xfer->layer_stride;
      }

      free(rgba);
   }
   done = TRUE;

end:
   if (map)
      pipe_transfer_unmap(pipe, tex_xfer);

   _mesa_unmap_pbo_dest(ctx, &ctx->Pack);
   pipe_resource_reference(&dst, NULL);

fallback:
   if (!done) {
      _mesa_GetTexSubImage_sw(ctx, xoffset, yoffset, zoffset,
                              width, height, depth,
                              format, type, pixels, texImage);
   }
}


/**
 * Do a CopyTexSubImage operation using a read transfer from the source,
 * a write transfer to the destination and get_tile()/put_tile() to access
 * the pixels/texels.
 *
 * Note: srcY=0=TOP of renderbuffer
 */
static void
fallback_copy_texsubimage(struct gl_context *ctx,
                          struct st_renderbuffer *strb,
                          struct st_texture_image *stImage,
                          GLenum baseFormat,
                          GLint destX, GLint destY, GLint slice,
                          GLint srcX, GLint srcY,
                          GLsizei width, GLsizei height)
{
   struct st_context *st = st_context(ctx);
   struct pipe_context *pipe = st->pipe;
   struct pipe_transfer *src_trans;
   GLubyte *texDest;
   enum pipe_transfer_usage transfer_usage;
   void *map;
   unsigned dst_width = width;
   unsigned dst_height = height;
   unsigned dst_depth = 1;
   struct pipe_transfer *transfer;

   if (ST_DEBUG & DEBUG_FALLBACK)
      debug_printf("%s: fallback processing\n", __func__);

   if (st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP) {
      srcY = strb->Base.Height - srcY - height;
   }

   map = pipe_transfer_map(pipe,
                           strb->texture,
                           strb->surface->u.tex.level,
                           strb->surface->u.tex.first_layer,
                           PIPE_TRANSFER_READ,
                           srcX, srcY,
                           width, height, &src_trans);

   if ((baseFormat == GL_DEPTH_COMPONENT ||
        baseFormat == GL_DEPTH_STENCIL) &&
       util_format_is_depth_and_stencil(stImage->pt->format))
      transfer_usage = PIPE_TRANSFER_READ_WRITE;
   else
      transfer_usage = PIPE_TRANSFER_WRITE;

   texDest = st_texture_image_map(st, stImage, transfer_usage,
                                  destX, destY, slice,
                                  dst_width, dst_height, dst_depth,
                                  &transfer);

   if (baseFormat == GL_DEPTH_COMPONENT ||
       baseFormat == GL_DEPTH_STENCIL) {
      const GLboolean scaleOrBias = (ctx->Pixel.DepthScale != 1.0F ||
                                     ctx->Pixel.DepthBias != 0.0F);
      GLint row, yStep;
      uint *data;

      /* determine bottom-to-top vs. top-to-bottom order for src buffer */
      if (st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP) {
         srcY = height - 1;
         yStep = -1;
      }
      else {
         srcY = 0;
         yStep = 1;
      }

      data = malloc(width * sizeof(uint));

      if (data) {
         /* To avoid a large temp memory allocation, do copy row by row */
         for (row = 0; row < height; row++, srcY += yStep) {
            pipe_get_tile_z(src_trans, map, 0, srcY, width, 1, data);
            if (scaleOrBias) {
               _mesa_scale_and_bias_depth_uint(ctx, width, data);
            }

            if (stImage->pt->target == PIPE_TEXTURE_1D_ARRAY) {
               pipe_put_tile_z(transfer, texDest + row*transfer->layer_stride,
                               0, 0, width, 1, data);
            }
            else {
               pipe_put_tile_z(transfer, texDest, 0, row, width, 1, data);
            }
         }
      }
      else {
         _mesa_error(ctx, GL_OUT_OF_MEMORY, "glCopyTexSubImage()");
      }

      free(data);
   }
   else {
      /* RGBA format */
      GLfloat *tempSrc =
         malloc(width * height * 4 * sizeof(GLfloat));

      if (tempSrc && texDest) {
         const GLint dims = 2;
         GLint dstRowStride;
         struct gl_texture_image *texImage = &stImage->base;
         struct gl_pixelstore_attrib unpack = ctx->DefaultPacking;

         if (st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP) {
            unpack.Invert = GL_TRUE;
         }

         if (stImage->pt->target == PIPE_TEXTURE_1D_ARRAY) {
            dstRowStride = transfer->layer_stride;
         }
         else {
            dstRowStride = transfer->stride;
         }

         /* get float/RGBA image from framebuffer */
         /* XXX this usually involves a lot of int/float conversion.
          * try to avoid that someday.
          */
         pipe_get_tile_rgba_format(src_trans, map, 0, 0, width, height,
                                   util_format_linear(strb->texture->format),
                                   tempSrc);

         /* Store into texture memory.
          * Note that this does some special things such as pixel transfer
          * ops and format conversion.  In particular, if the dest tex format
          * is actually RGBA but the user created the texture as GL_RGB we
          * need to fill-in/override the alpha channel with 1.0.
          */
         _mesa_texstore(ctx, dims,
                        texImage->_BaseFormat, 
                        texImage->TexFormat, 
                        dstRowStride,
                        &texDest,
                        width, height, 1,
                        GL_RGBA, GL_FLOAT, tempSrc, /* src */
                        &unpack);
      }
      else {
         _mesa_error(ctx, GL_OUT_OF_MEMORY, "glTexSubImage");
      }

      free(tempSrc);
   }

   st_texture_image_unmap(st, stImage, slice);
   pipe->transfer_unmap(pipe, src_trans);
}

static bool
st_can_copyteximage_using_blit(const struct gl_texture_image *texImage,
                               const struct gl_renderbuffer *rb)
{
   GLenum tex_baseformat = _mesa_get_format_base_format(texImage->TexFormat);

   /* We don't blit to a teximage where the GL base format doesn't match the
    * texture's chosen format, except in the case of a GL_RGB texture
    * represented with GL_RGBA (where the alpha channel is just being
    * dropped).
    */
   if (texImage->_BaseFormat != tex_baseformat &&
       ((texImage->_BaseFormat != GL_RGB || tex_baseformat != GL_RGBA))) {
      return false;
   }

   /* We can't blit from a RB where the GL base format doesn't match the RB's
    * chosen format (for example, GL RGB or ALPHA with rb->Format of an RGBA
    * type, because the other channels will be undefined).
    */
   if (rb->_BaseFormat != _mesa_get_format_base_format(rb->Format))
      return false;

   return true;
}

/**
 * Do a CopyTex[Sub]Image1/2/3D() using a hardware (blit) path if possible.
 * Note that the region to copy has already been clipped so we know we
 * won't read from outside the source renderbuffer's bounds.
 *
 * Note: srcY=0=Bottom of renderbuffer (GL convention)
 */
static void
st_CopyTexSubImage(struct gl_context *ctx, GLuint dims,
                   struct gl_texture_image *texImage,
                   GLint destX, GLint destY, GLint slice,
                   struct gl_renderbuffer *rb,
                   GLint srcX, GLint srcY, GLsizei width, GLsizei height)
{
   struct st_texture_image *stImage = st_texture_image(texImage);
   struct st_texture_object *stObj = st_texture_object(texImage->TexObject);
   struct st_renderbuffer *strb = st_renderbuffer(rb);
   struct st_context *st = st_context(ctx);
   struct pipe_context *pipe = st->pipe;
   struct pipe_screen *screen = pipe->screen;
   struct pipe_blit_info blit;
   enum pipe_format dst_format;
   GLboolean do_flip = (st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP);
   unsigned bind;
   GLint srcY0, srcY1;

   st_flush_bitmap_cache(st);
   st_invalidate_readpix_cache(st);

   assert(!_mesa_is_format_etc2(texImage->TexFormat) &&
          !_mesa_is_format_astc_2d(texImage->TexFormat) &&
          texImage->TexFormat != MESA_FORMAT_ETC1_RGB8);

   if (!strb || !strb->surface || !stImage->pt) {
      debug_printf("%s: null strb or stImage\n", __func__);
      return;
   }

   if (_mesa_texstore_needs_transfer_ops(ctx, texImage->_BaseFormat,
                                         texImage->TexFormat)) {
      goto fallback;
   }

   if (!st_can_copyteximage_using_blit(texImage, rb)) {
      goto fallback;
   }

   /* Choose the destination format to match the TexImage behavior. */
   dst_format = util_format_linear(stImage->pt->format);
   dst_format = util_format_luminance_to_red(dst_format);
   dst_format = util_format_intensity_to_red(dst_format);

   /* See if the destination format is supported. */
   if (texImage->_BaseFormat == GL_DEPTH_STENCIL ||
       texImage->_BaseFormat == GL_DEPTH_COMPONENT) {
      bind = PIPE_BIND_DEPTH_STENCIL;
   }
   else {
      bind = PIPE_BIND_RENDER_TARGET;
   }

   if (!dst_format ||
       !screen->is_format_supported(screen, dst_format, stImage->pt->target,
                                    stImage->pt->nr_samples, bind)) {
      goto fallback;
   }

   /* Y flipping for the main framebuffer. */
   if (do_flip) {
      srcY1 = strb->Base.Height - srcY - height;
      srcY0 = srcY1 + height;
   }
   else {
      srcY0 = srcY;
      srcY1 = srcY0 + height;
   }

   /* Blit the texture.
    * This supports flipping, format conversions, and downsampling.
    */
   memset(&blit, 0, sizeof(blit));
   blit.src.resource = strb->texture;
   blit.src.format = util_format_linear(strb->surface->format);
   blit.src.level = strb->surface->u.tex.level;
   blit.src.box.x = srcX;
   blit.src.box.y = srcY0;
   blit.src.box.z = strb->surface->u.tex.first_layer;
   blit.src.box.width = width;
   blit.src.box.height = srcY1 - srcY0;
   blit.src.box.depth = 1;
   blit.dst.resource = stImage->pt;
   blit.dst.format = dst_format;
   blit.dst.level = stObj->pt != stImage->pt ? 0 : texImage->Level + texImage->TexObject->MinLevel;
   blit.dst.box.x = destX;
   blit.dst.box.y = destY;
   blit.dst.box.z = stImage->base.Face + slice + texImage->TexObject->MinLayer;
   blit.dst.box.width = width;
   blit.dst.box.height = height;
   blit.dst.box.depth = 1;
   blit.mask = st_get_blit_mask(rb->_BaseFormat, texImage->_BaseFormat);
   blit.filter = PIPE_TEX_FILTER_NEAREST;
   pipe->blit(pipe, &blit);
   return;

fallback:
   /* software fallback */
   fallback_copy_texsubimage(ctx,
                             strb, stImage, texImage->_BaseFormat,
                             destX, destY, slice,
                             srcX, srcY, width, height);
}


/**
 * Copy image data from stImage into the texture object 'stObj' at level
 * 'dstLevel'.
 */
static void
copy_image_data_to_texture(struct st_context *st,
                           struct st_texture_object *stObj,
                           GLuint dstLevel,
                           struct st_texture_image *stImage)
{
   /* debug checks */
   {
      const struct gl_texture_image MAYBE_UNUSED *dstImage =
         stObj->base.Image[stImage->base.Face][dstLevel];
      assert(dstImage);
      assert(dstImage->Width == stImage->base.Width);
      assert(dstImage->Height == stImage->base.Height);
      assert(dstImage->Depth == stImage->base.Depth);
   }

   if (stImage->pt) {
      /* Copy potentially with the blitter:
       */
      GLuint src_level;
      if (stImage->pt->last_level == 0)
         src_level = 0;
      else
         src_level = stImage->base.Level;

      assert(src_level <= stImage->pt->last_level);
      assert(u_minify(stImage->pt->width0, src_level) == stImage->base.Width);
      assert(stImage->pt->target == PIPE_TEXTURE_1D_ARRAY ||
             u_minify(stImage->pt->height0, src_level) == stImage->base.Height);
      assert(stImage->pt->target == PIPE_TEXTURE_2D_ARRAY ||
             stImage->pt->target == PIPE_TEXTURE_CUBE_ARRAY ||
             u_minify(stImage->pt->depth0, src_level) == stImage->base.Depth);

      st_texture_image_copy(st->pipe,
                            stObj->pt, dstLevel,  /* dest texture, level */
                            stImage->pt, src_level, /* src texture, level */
                            stImage->base.Face);

      pipe_resource_reference(&stImage->pt, NULL);
   }
   pipe_resource_reference(&stImage->pt, stObj->pt);
}


/**
 * Called during state validation.  When this function is finished,
 * the texture object should be ready for rendering.
 * \return GL_TRUE for success, GL_FALSE for failure (out of mem)
 */
GLboolean
st_finalize_texture(struct gl_context *ctx,
                    struct pipe_context *pipe,
                    struct gl_texture_object *tObj,
                    GLuint cubeMapFace)
{
   struct st_context *st = st_context(ctx);
   struct st_texture_object *stObj = st_texture_object(tObj);
   const GLuint nr_faces = _mesa_num_tex_faces(stObj->base.Target);
   GLuint face;
   const struct st_texture_image *firstImage;
   enum pipe_format firstImageFormat;
   unsigned ptWidth;
   uint16_t ptHeight, ptDepth, ptLayers, ptNumSamples;

   if (tObj->Immutable)
      return GL_TRUE;

   if (tObj->_MipmapComplete)
      stObj->lastLevel = stObj->base._MaxLevel;
   else if (tObj->_BaseComplete)
      stObj->lastLevel = stObj->base.BaseLevel;

   /* Skip the loop over images in the common case of no images having
    * changed.  But if the GL_BASE_LEVEL or GL_MAX_LEVEL change to something we
    * haven't looked at, then we do need to look at those new images.
    */
   if (!stObj->needs_validation &&
       stObj->base.BaseLevel >= stObj->validated_first_level &&
       stObj->lastLevel <= stObj->validated_last_level) {
      return GL_TRUE;
   }

   /* If this texture comes from a window system, there is nothing else to do. */
   if (stObj->surface_based) {
      return GL_TRUE;
   }

   firstImage = st_texture_image_const(stObj->base.Image[cubeMapFace][stObj->base.BaseLevel]);
   assert(firstImage);

   /* If both firstImage and stObj point to a texture which can contain
    * all active images, favour firstImage.  Note that because of the
    * completeness requirement, we know that the image dimensions
    * will match.
    */
   if (firstImage->pt &&
       firstImage->pt != stObj->pt &&
       (!stObj->pt || firstImage->pt->last_level >= stObj->pt->last_level)) {
      pipe_resource_reference(&stObj->pt, firstImage->pt);
      st_texture_release_all_sampler_views(st, stObj);
   }

   /* Find gallium format for the Mesa texture */
   firstImageFormat =
      st_mesa_format_to_pipe_format(st, firstImage->base.TexFormat);

   /* Find size of level=0 Gallium mipmap image, plus number of texture layers */
   {
      unsigned width;
      uint16_t height, depth;

      st_gl_texture_dims_to_pipe_dims(stObj->base.Target,
                                      firstImage->base.Width2,
                                      firstImage->base.Height2,
                                      firstImage->base.Depth2,
                                      &width, &height, &depth, &ptLayers);

      /* If we previously allocated a pipe texture and its sizes are
       * compatible, use them.
       */
      if (stObj->pt &&
          u_minify(stObj->pt->width0, firstImage->base.Level) == width &&
          u_minify(stObj->pt->height0, firstImage->base.Level) == height &&
          u_minify(stObj->pt->depth0, firstImage->base.Level) == depth) {
         ptWidth = stObj->pt->width0;
         ptHeight = stObj->pt->height0;
         ptDepth = stObj->pt->depth0;
      } else {
         /* Otherwise, compute a new level=0 size that is compatible with the
          * base level image.
          */
         ptWidth = width > 1 ? width << firstImage->base.Level : 1;
         ptHeight = height > 1 ? height << firstImage->base.Level : 1;
         ptDepth = depth > 1 ? depth << firstImage->base.Level : 1;

         /* If the base level image is 1x1x1, we still need to ensure that the
          * resulting pipe texture ends up with the required number of levels
          * in total.
          */
         if (ptWidth == 1 && ptHeight == 1 && ptDepth == 1) {
            ptWidth <<= firstImage->base.Level;

            if (stObj->base.Target == GL_TEXTURE_CUBE_MAP ||
                stObj->base.Target == GL_TEXTURE_CUBE_MAP_ARRAY)
               ptHeight = ptWidth;
         }

         /* At this point, the texture may be incomplete (mismatched cube
          * face sizes, for example).  If that's the case, give up, but
          * don't return GL_FALSE as that would raise an incorrect
          * GL_OUT_OF_MEMORY error.  See Piglit fbo-incomplete-texture-03 test.
          */
         if (!stObj->base._BaseComplete) {
            _mesa_test_texobj_completeness(ctx, &stObj->base);
            if (!stObj->base._BaseComplete) {
               return TRUE;
            }
         }
      }

      ptNumSamples = firstImage->base.NumSamples;
   }

   /* If we already have a gallium texture, check that it matches the texture
    * object's format, target, size, num_levels, etc.
    */
   if (stObj->pt) {
      if (stObj->pt->target != gl_target_to_pipe(stObj->base.Target) ||
          stObj->pt->format != firstImageFormat ||
          stObj->pt->last_level < stObj->lastLevel ||
          stObj->pt->width0 != ptWidth ||
          stObj->pt->height0 != ptHeight ||
          stObj->pt->depth0 != ptDepth ||
          stObj->pt->nr_samples != ptNumSamples ||
          stObj->pt->array_size != ptLayers)
      {
         /* The gallium texture does not match the Mesa texture so delete the
          * gallium texture now.  We'll make a new one below.
          */
         pipe_resource_reference(&stObj->pt, NULL);
         st_texture_release_all_sampler_views(st, stObj);
         st->dirty |= ST_NEW_FRAMEBUFFER;
      }
   }

   /* May need to create a new gallium texture:
    */
   if (!stObj->pt) {
      GLuint bindings = default_bindings(st, firstImageFormat);

      stObj->pt = st_texture_create(st,
                                    gl_target_to_pipe(stObj->base.Target),
                                    firstImageFormat,
                                    stObj->lastLevel,
                                    ptWidth,
                                    ptHeight,
                                    ptDepth,
                                    ptLayers, ptNumSamples,
                                    bindings);

      if (!stObj->pt) {
         _mesa_error(ctx, GL_OUT_OF_MEMORY, "glTexImage");
         return GL_FALSE;
      }
   }

   /* Pull in any images not in the object's texture:
    */
   for (face = 0; face < nr_faces; face++) {
      GLuint level;
      for (level = stObj->base.BaseLevel; level <= stObj->lastLevel; level++) {
         struct st_texture_image *stImage =
            st_texture_image(stObj->base.Image[face][level]);

         /* Need to import images in main memory or held in other textures.
          */
         if (stImage && stObj->pt != stImage->pt) {
            GLuint height;
            GLuint depth;

            if (stObj->base.Target != GL_TEXTURE_1D_ARRAY)
               height = u_minify(ptHeight, level);
            else
               height = ptLayers;

            if (stObj->base.Target == GL_TEXTURE_3D)
               depth = u_minify(ptDepth, level);
            else if (stObj->base.Target == GL_TEXTURE_CUBE_MAP)
               depth = 1;
            else
               depth = ptLayers;

            if (level == 0 ||
                (stImage->base.Width == u_minify(ptWidth, level) &&
                 stImage->base.Height == height &&
                 stImage->base.Depth == depth)) {
               /* src image fits expected dest mipmap level size */
               copy_image_data_to_texture(st, stObj, level, stImage);
            }
         }
      }
   }

   stObj->validated_first_level = stObj->base.BaseLevel;
   stObj->validated_last_level = stObj->lastLevel;
   stObj->needs_validation = false;

   return GL_TRUE;
}

/**
 * Allocate a new pipe_resource object
 * width0, height0, depth0 are the dimensions of the level 0 image
 * (the highest resolution).  last_level indicates how many mipmap levels
 * to allocate storage for.  For non-mipmapped textures, this will be zero.
 */
static struct pipe_resource *
st_texture_create_from_memory(struct st_context *st,
                              struct st_memory_object *memObj,
                              GLuint64 offset,
                              enum pipe_texture_target target,
                              enum pipe_format format,
                              GLuint last_level,
                              GLuint width0,
                              GLuint height0,
                              GLuint depth0,
                              GLuint layers,
                              GLuint nr_samples,
                              GLuint bind )
{
   struct pipe_resource pt, *newtex;
   struct pipe_screen *screen = st->pipe->screen;

   assert(target < PIPE_MAX_TEXTURE_TYPES);
   assert(width0 > 0);
   assert(height0 > 0);
   assert(depth0 > 0);
   if (target == PIPE_TEXTURE_CUBE)
      assert(layers == 6);

   DBG("%s target %d format %s last_level %d\n", __func__,
       (int) target, util_format_name(format), last_level);

   assert(format);
   assert(screen->is_format_supported(screen, format, target, 0,
                                      PIPE_BIND_SAMPLER_VIEW));

   memset(&pt, 0, sizeof(pt));
   pt.target = target;
   pt.format = format;
   pt.last_level = last_level;
   pt.width0 = width0;
   pt.height0 = height0;
   pt.depth0 = depth0;
   pt.array_size = layers;
   pt.usage = PIPE_USAGE_DEFAULT;
   pt.bind = bind;
   /* only set this for OpenGL textures, not renderbuffers */
   pt.flags = PIPE_RESOURCE_FLAG_TEXTURING_MORE_LIKELY;
   pt.nr_samples = nr_samples;

   newtex = screen->resource_from_memobj(screen, &pt, memObj->memory, offset);

   assert(!newtex || pipe_is_referenced(&newtex->reference));

   return newtex;
}

/**
 * Allocate texture memory for a whole mipmap stack.
 * Note: for multisample textures if the requested sample count is not
 * supported, we search for the next higher supported sample count.
 */
static GLboolean
st_texture_storage(struct gl_context *ctx,
                   struct gl_texture_object *texObj,
                   GLsizei levels, GLsizei width,
                   GLsizei height, GLsizei depth,
                   struct gl_memory_object *memObj,
                   GLuint64 offset)
{
   const GLuint numFaces = _mesa_num_tex_faces(texObj->Target);
   struct gl_texture_image *texImage = texObj->Image[0][0];
   struct st_context *st = st_context(ctx);
   struct st_texture_object *stObj = st_texture_object(texObj);
   struct st_memory_object *smObj = st_memory_object(memObj);
   struct pipe_screen *screen = st->pipe->screen;
   unsigned ptWidth, bindings;
   uint16_t ptHeight, ptDepth, ptLayers;
   enum pipe_format fmt;
   GLint level;
   GLuint num_samples = texImage->NumSamples;

   assert(levels > 0);

   stObj->lastLevel = levels - 1;

   fmt = st_mesa_format_to_pipe_format(st, texImage->TexFormat);

   bindings = default_bindings(st, fmt);

   if (num_samples > 0) {
      /* Find msaa sample count which is actually supported.  For example,
       * if the user requests 1x but only 4x or 8x msaa is supported, we'll
       * choose 4x here.
       */
      enum pipe_texture_target ptarget = gl_target_to_pipe(texObj->Target);
      boolean found = FALSE;

      if (ctx->Const.MaxSamples > 1 && num_samples == 1) {
         /* don't try num_samples = 1 with drivers that support real msaa */
         num_samples = 2;
      }

      for (; num_samples <= ctx->Const.MaxSamples; num_samples++) {
         if (screen->is_format_supported(screen, fmt, ptarget,
                                         num_samples,
                                         PIPE_BIND_SAMPLER_VIEW)) {
            /* Update the sample count in gl_texture_image as well. */
            texImage->NumSamples = num_samples;
            found = TRUE;
            break;
         }
      }

      if (!found) {
         return GL_FALSE;
      }
   }

   st_gl_texture_dims_to_pipe_dims(texObj->Target,
                                   width, height, depth,
                                   &ptWidth, &ptHeight, &ptDepth, &ptLayers);

   if (smObj) {
      stObj->pt = st_texture_create_from_memory(st,
                                                smObj,
                                                offset,
                                                gl_target_to_pipe(texObj->Target),
                                                fmt,
                                                levels - 1,
                                                ptWidth,
                                                ptHeight,
                                                ptDepth,
                                                ptLayers, num_samples,
                                                bindings);
   }
   else {
      stObj->pt = st_texture_create(st,
                                    gl_target_to_pipe(texObj->Target),
                                    fmt,
                                    levels - 1,
                                    ptWidth,
                                    ptHeight,
                                    ptDepth,
                                    ptLayers, num_samples,
                                    bindings);
   }

   if (!stObj->pt)
      return GL_FALSE;

   /* Set image resource pointers */
   for (level = 0; level < levels; level++) {
      GLuint face;
      for (face = 0; face < numFaces; face++) {
         struct st_texture_image *stImage =
            st_texture_image(texObj->Image[face][level]);
         pipe_resource_reference(&stImage->pt, stObj->pt);

         compressed_tex_fallback_allocate(st, stImage);
      }
   }

   /* The texture is in a validated state, so no need to check later. */
   stObj->needs_validation = false;
   stObj->validated_first_level = 0;
   stObj->validated_last_level = levels - 1;

   return GL_TRUE;
}

/**
 * Called via ctx->Driver.AllocTextureStorage() to allocate texture memory
 * for a whole mipmap stack.
 */
static GLboolean
st_AllocTextureStorage(struct gl_context *ctx,
                       struct gl_texture_object *texObj,
                       GLsizei levels, GLsizei width,
                       GLsizei height, GLsizei depth)
{
   return st_texture_storage(ctx, texObj, levels,
                             width, height, depth,
                             NULL, 0);
}


static GLboolean
st_TestProxyTexImage(struct gl_context *ctx, GLenum target,
                     GLuint numLevels, GLint level,
                     mesa_format format, GLuint numSamples,
                     GLint width, GLint height, GLint depth)
{
   struct st_context *st = st_context(ctx);
   struct pipe_context *pipe = st->pipe;

   if (width == 0 || height == 0 || depth == 0) {
      /* zero-sized images are legal, and always fit! */
      return GL_TRUE;
   }

   if (pipe->screen->can_create_resource) {
      /* Ask the gallium driver if the texture is too large */
      struct gl_texture_object *texObj =
         _mesa_get_current_tex_object(ctx, target);
      struct pipe_resource pt;

      /* Setup the pipe_resource object
       */
      memset(&pt, 0, sizeof(pt));

      pt.target = gl_target_to_pipe(target);
      pt.format = st_mesa_format_to_pipe_format(st, format);
      pt.nr_samples = numSamples;

      st_gl_texture_dims_to_pipe_dims(target,
                                      width, height, depth,
                                      &pt.width0, &pt.height0,
                                      &pt.depth0, &pt.array_size);

      if (numLevels > 0) {
         /* For immutable textures we know the final number of mip levels */
         pt.last_level = numLevels - 1;
      }
      else if (level == 0 && (texObj->Sampler.MinFilter == GL_LINEAR ||
                              texObj->Sampler.MinFilter == GL_NEAREST)) {
         /* assume just one mipmap level */
         pt.last_level = 0;
      }
      else {
         /* assume a full set of mipmaps */
         pt.last_level = _mesa_logbase2(MAX3(width, height, depth));
      }

      return pipe->screen->can_create_resource(pipe->screen, &pt);
   }
   else {
      /* Use core Mesa fallback */
      return _mesa_test_proxy_teximage(ctx, target, numLevels, level, format,
                                       numSamples, width, height, depth);
   }
}

static GLboolean
st_TextureView(struct gl_context *ctx,
               struct gl_texture_object *texObj,
               struct gl_texture_object *origTexObj)
{
   struct st_context *st = st_context(ctx);
   struct st_texture_object *orig = st_texture_object(origTexObj);
   struct st_texture_object *tex = st_texture_object(texObj);
   struct gl_texture_image *image = texObj->Image[0][0];

   const int numFaces = _mesa_num_tex_faces(texObj->Target);
   const int numLevels = texObj->NumLevels;

   int face;
   int level;

   pipe_resource_reference(&tex->pt, orig->pt);

   /* Set image resource pointers */
   for (level = 0; level < numLevels; level++) {
      for (face = 0; face < numFaces; face++) {
         struct st_texture_image *stImage =
            st_texture_image(texObj->Image[face][level]);
         pipe_resource_reference(&stImage->pt, tex->pt);
      }
   }

   tex->surface_based = GL_TRUE;
   tex->surface_format =
      st_mesa_format_to_pipe_format(st_context(ctx), image->TexFormat);

   tex->lastLevel = numLevels - 1;

   /* free texture sampler views.  They need to be recreated when we
    * change the texture view parameters.
    */
   st_texture_release_all_sampler_views(st, tex);

   /* The texture is in a validated state, so no need to check later. */
   tex->needs_validation = false;
   tex->validated_first_level = 0;
   tex->validated_last_level = numLevels - 1;

   return GL_TRUE;
}


/**
 * Find the mipmap level in 'pt' which matches the level described by
 * 'texImage'.
 */
static unsigned
find_mipmap_level(const struct gl_texture_image *texImage,
                  const struct pipe_resource *pt)
{
   const GLenum target = texImage->TexObject->Target;
   GLint texWidth = texImage->Width;
   GLint texHeight = texImage->Height;
   GLint texDepth = texImage->Depth;
   unsigned level, w;
   uint16_t h, d, layers;

   st_gl_texture_dims_to_pipe_dims(target, texWidth, texHeight, texDepth,
                                   &w, &h, &d, &layers);

   for (level = 0; level <= pt->last_level; level++) {
      if (u_minify(pt->width0, level) == w &&
          u_minify(pt->height0, level) == h &&
          u_minify(pt->depth0, level) == d) {
         return level;
      }
   }

   /* If we get here, there must be some sort of inconsistency between
    * the Mesa texture object/images and the gallium resource.
    */
   debug_printf("Inconsistent textures in find_mipmap_level()\n");

   return texImage->Level;
}


static void
st_ClearTexSubImage(struct gl_context *ctx,
                    struct gl_texture_image *texImage,
                    GLint xoffset, GLint yoffset, GLint zoffset,
                    GLsizei width, GLsizei height, GLsizei depth,
                    const void *clearValue)
{
   static const char zeros[16] = {0};
   struct gl_texture_object *texObj = texImage->TexObject;
   struct st_texture_image *stImage = st_texture_image(texImage);
   struct pipe_resource *pt = stImage->pt;
   struct st_context *st = st_context(ctx);
   struct pipe_context *pipe = st->pipe;
   unsigned level;
   struct pipe_box box;

   if (!pt)
      return;

   st_flush_bitmap_cache(st);
   st_invalidate_readpix_cache(st);

   u_box_3d(xoffset, yoffset, zoffset + texImage->Face,
            width, height, depth, &box);
   if (texObj->Immutable) {
      /* The texture object has to be consistent (no "loose", per-image
       * gallium resources).  If this texture is a view into another
       * texture, we have to apply the MinLevel/Layer offsets.  If this is
       * not a texture view, the offsets will be zero.
       */
      assert(stImage->pt == st_texture_object(texObj)->pt);
      level = texImage->Level + texObj->MinLevel;
      box.z += texObj->MinLayer;
   }
   else {
      /* Texture level sizes may be inconsistent.  We my have "loose",
       * per-image gallium resources.  The texImage->Level may not match
       * the gallium resource texture level.
       */
      level = find_mipmap_level(texImage, pt);
   }

   assert(level <= pt->last_level);

   pipe->clear_texture(pipe, pt, level, &box, clearValue ? clearValue : zeros);
}


/**
 * Called via the glTexParam*() function, but only when some texture object
 * state has actually changed.
 */
static void
st_TexParameter(struct gl_context *ctx,
                struct gl_texture_object *texObj, GLenum pname)
{
   struct st_context *st = st_context(ctx);
   struct st_texture_object *stObj = st_texture_object(texObj);

   switch (pname) {
   case GL_TEXTURE_BASE_LEVEL:
   case GL_TEXTURE_MAX_LEVEL:
   case GL_DEPTH_TEXTURE_MODE:
   case GL_DEPTH_STENCIL_TEXTURE_MODE:
   case GL_TEXTURE_SRGB_DECODE_EXT:
   case GL_TEXTURE_SWIZZLE_R:
   case GL_TEXTURE_SWIZZLE_G:
   case GL_TEXTURE_SWIZZLE_B:
   case GL_TEXTURE_SWIZZLE_A:
   case GL_TEXTURE_SWIZZLE_RGBA:
   case GL_TEXTURE_BUFFER_SIZE:
   case GL_TEXTURE_BUFFER_OFFSET:
      /* changing any of these texture parameters means we must create
       * new sampler views.
       */
      st_texture_release_all_sampler_views(st, stObj);
      break;
   default:
      ; /* nothing */
   }
}

static GLboolean
st_SetTextureStorageForMemoryObject(struct gl_context *ctx,
                                    struct gl_texture_object *texObj,
                                    struct gl_memory_object *memObj,
                                    GLsizei levels, GLsizei width,
                                    GLsizei height, GLsizei depth,
                                    GLuint64 offset)
{
   return st_texture_storage(ctx, texObj, levels,
                             width, height, depth,
                             memObj, offset);
}

static GLuint64
st_NewTextureHandle(struct gl_context *ctx, struct gl_texture_object *texObj,
                    struct gl_sampler_object *sampObj)
{
   struct st_context *st = st_context(ctx);
   struct st_texture_object *stObj = st_texture_object(texObj);
   struct pipe_context *pipe = st->pipe;
   struct pipe_sampler_view *view;
   struct pipe_sampler_state sampler = {0};

   if (texObj->Target != GL_TEXTURE_BUFFER) {
      if (!st_finalize_texture(ctx, pipe, texObj, 0))
         return 0;

      st_convert_sampler(st, texObj, sampObj, 0, &sampler);

      /* TODO: Clarify the interaction of ARB_bindless_texture and EXT_texture_sRGB_decode */
      view = st_get_texture_sampler_view_from_stobj(st, stObj, sampObj, 0, true);
   } else {
      view = st_get_buffer_sampler_view_from_stobj(st, stObj);
   }

   return pipe->create_texture_handle(pipe, view, &sampler);
}


static void
st_DeleteTextureHandle(struct gl_context *ctx, GLuint64 handle)
{
   struct st_context *st = st_context(ctx);
   struct pipe_context *pipe = st->pipe;

   pipe->delete_texture_handle(pipe, handle);
}


static void
st_MakeTextureHandleResident(struct gl_context *ctx, GLuint64 handle,
                             bool resident)
{
   struct st_context *st = st_context(ctx);
   struct pipe_context *pipe = st->pipe;

   pipe->make_texture_handle_resident(pipe, handle, resident);
}


static GLuint64
st_NewImageHandle(struct gl_context *ctx, struct gl_image_unit *imgObj)
{
   struct st_context *st = st_context(ctx);
   struct pipe_context *pipe = st->pipe;
   struct pipe_image_view image;

   st_convert_image(st, imgObj, &image);

   return pipe->create_image_handle(pipe, &image);
}


static void
st_DeleteImageHandle(struct gl_context *ctx, GLuint64 handle)
{
   struct st_context *st = st_context(ctx);
   struct pipe_context *pipe = st->pipe;

   pipe->delete_image_handle(pipe, handle);
}


static void
st_MakeImageHandleResident(struct gl_context *ctx, GLuint64 handle,
                           GLenum access, bool resident)
{
   struct st_context *st = st_context(ctx);
   struct pipe_context *pipe = st->pipe;

   pipe->make_image_handle_resident(pipe, handle, access, resident);
}


void
st_init_texture_functions(struct dd_function_table *functions)
{
   functions->ChooseTextureFormat = st_ChooseTextureFormat;
   functions->QueryInternalFormat = st_QueryInternalFormat;
   functions->TexImage = st_TexImage;
   functions->TexSubImage = st_TexSubImage;
   functions->CompressedTexSubImage = st_CompressedTexSubImage;
   functions->CopyTexSubImage = st_CopyTexSubImage;
   functions->GenerateMipmap = st_generate_mipmap;

   functions->GetTexSubImage = st_GetTexSubImage;

   /* compressed texture functions */
   functions->CompressedTexImage = st_CompressedTexImage;

   functions->NewTextureObject = st_NewTextureObject;
   functions->NewTextureImage = st_NewTextureImage;
   functions->DeleteTextureImage = st_DeleteTextureImage;
   functions->DeleteTexture = st_DeleteTextureObject;
   functions->AllocTextureImageBuffer = st_AllocTextureImageBuffer;
   functions->FreeTextureImageBuffer = st_FreeTextureImageBuffer;
   functions->MapTextureImage = st_MapTextureImage;
   functions->UnmapTextureImage = st_UnmapTextureImage;

   /* XXX Temporary until we can query pipe's texture sizes */
   functions->TestProxyTexImage = st_TestProxyTexImage;

   functions->AllocTextureStorage = st_AllocTextureStorage;
   functions->TextureView = st_TextureView;
   functions->ClearTexSubImage = st_ClearTexSubImage;

   functions->TexParameter = st_TexParameter;

   /* bindless functions */
   functions->NewTextureHandle = st_NewTextureHandle;
   functions->DeleteTextureHandle = st_DeleteTextureHandle;
   functions->MakeTextureHandleResident = st_MakeTextureHandleResident;
   functions->NewImageHandle = st_NewImageHandle;
   functions->DeleteImageHandle = st_DeleteImageHandle;
   functions->MakeImageHandleResident = st_MakeImageHandleResident;

   /* external object functions */
   functions->SetTextureStorageForMemoryObject = st_SetTextureStorageForMemoryObject;
}