src/mesa/drivers/dri/i965/intel_pixel_read.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2003 VMware, Inc.
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  21  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
  22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28 #include "main/glheader.h"
  29 #include "main/enums.h"
  30 #include "main/mtypes.h"
  31 #include "main/macros.h"
  32 #include "main/fbobject.h"
  33 #include "main/image.h"
  34 #include "main/bufferobj.h"
  35 #include "main/readpix.h"
  36 #include "main/state.h"
  37 #include "main/glformats.h"
  38 #include "drivers/common/meta.h"
  39
  40 #include "brw_context.h"
  41 #include "intel_screen.h"
  42 #include "intel_batchbuffer.h"
  43 #include "intel_blit.h"
  44 #include "intel_buffers.h"
  45 #include "intel_fbo.h"
  46 #include "intel_mipmap_tree.h"
  47 #include "intel_pixel.h"
  48 #include "intel_buffer_objects.h"
  49 #include "intel_tiled_memcpy.h"
  50
  51 #define FILE_DEBUG_FLAG DEBUG_PIXEL
  52
  53 /**
  54  * \brief A fast path for glReadPixels
  55  *
  56  * This fast path is taken when the source format is BGRA, RGBA,
  57  * A or L and when the texture memory is X- or Y-tiled.  It downloads
  58  * the source data by directly mapping the memory without a GTT fence.
  59  * This then needs to be de-tiled on the CPU before presenting the data to
  60  * the user in the linear fasion.
  61  *
  62  * This is a performance win over the conventional texture download path.
  63  * In the conventional texture download path, the texture is either mapped
  64  * through the GTT or copied to a linear buffer with the blitter before
  65  * handing off to a software path.  This allows us to avoid round-tripping
  66  * through the GPU (in the case where we would be blitting) and do only a
  67  * single copy operation.
  68  */
  69 static bool
  70 intel_readpixels_tiled_memcpy(struct gl_context * ctx,
  71                               GLint xoffset, GLint yoffset,
  72                               GLsizei width, GLsizei height,
  73                               GLenum format, GLenum type,
  74                               GLvoid * pixels,
  75                               const struct gl_pixelstore_attrib *pack)
  76 {
  77    struct brw_context *brw = brw_context(ctx);
  78    struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
  79
  80    /* This path supports reading from color buffers only */
  81    if (rb == NULL)
  82       return false;
  83
  84    struct intel_renderbuffer *irb = intel_renderbuffer(rb);
  85    int dst_pitch;
  86
  87    /* The miptree's buffer. */
  88    drm_intel_bo *bo;
  89
  90    int error = 0;
  91
  92    uint32_t cpp;
  93    mem_copy_fn mem_copy = NULL;
  94
  95    /* This fastpath is restricted to specific renderbuffer types:
  96     * a 2D BGRA, RGBA, L8 or A8 texture. It could be generalized to support
  97     * more types.
  98     */
  99    if (!brw->has_llc ||
 100        !(type == GL_UNSIGNED_BYTE || type == GL_UNSIGNED_INT_8_8_8_8_REV) ||
 101        pixels == NULL ||
 102        _mesa_is_bufferobj(pack->BufferObj) ||
 103        pack->Alignment > 4 ||
 104        pack->SkipPixels > 0 ||
 105        pack->SkipRows > 0 ||
 106        (pack->RowLength != 0 && pack->RowLength != width) ||
 107        pack->SwapBytes ||
 108        pack->LsbFirst ||
 109        pack->Invert)
 110       return false;
 111
 112    /* This renderbuffer can come from a texture.  In this case, we impose
 113     * some of the same restrictions we have for textures and adjust for
 114     * miplevels.
 115     */
 116    if (rb->TexImage) {
 117       if (rb->TexImage->TexObject->Target != GL_TEXTURE_2D &&
 118           rb->TexImage->TexObject->Target != GL_TEXTURE_RECTANGLE)
 119          return false;
 120
 121       int level = rb->TexImage->Level + rb->TexImage->TexObject->MinLevel;
 122
 123       /* Adjust x and y offset based on miplevel */
 124       xoffset += irb->mt->level[level].level_x;
 125       yoffset += irb->mt->level[level].level_y;
 126    }
 127
 128    /* It is possible that the renderbuffer (or underlying texture) is
 129     * multisampled.  Since ReadPixels from a multisampled buffer requires a
 130     * multisample resolve, we can't handle this here
 131     */
 132    if (rb->NumSamples > 1)
 133       return false;
 134
 135    /* We can't handle copying from RGBX or BGRX because the tiled_memcpy
 136     * function doesn't set the last channel to 1.
 137     */
 138    if (rb->Format == MESA_FORMAT_B8G8R8X8_UNORM ||
 139        rb->Format == MESA_FORMAT_R8G8B8X8_UNORM)
 140       return false;
 141
 142    if (!intel_get_memcpy(rb->Format, format, type, &mem_copy, &cpp,
 143                          INTEL_DOWNLOAD))
 144       return false;
 145
 146    if (!irb->mt ||
 147        (irb->mt->tiling != I915_TILING_X &&
 148        irb->mt->tiling != I915_TILING_Y)) {
 149       /* The algorithm is written only for X- or Y-tiled memory. */
 150       return false;
 151    }
 152
 153    /* Since we are going to read raw data to the miptree, we need to resolve
 154     * any pending fast color clears before we start.
 155     */
 156    intel_miptree_resolve_color(brw, irb->mt);
 157
 158    bo = irb->mt->bo;
 159
 160    if (drm_intel_bo_references(brw->batch.bo, bo)) {
 161       perf_debug("Flushing before mapping a referenced bo.\n");
 162       intel_batchbuffer_flush(brw);
 163    }
 164
 165    error = brw_bo_map(brw, bo, false /* write enable */, "miptree");
 166    if (error) {
 167       DBG("%s: failed to map bo\n", __func__);
 168       return false;
 169    }
 170
 171    dst_pitch = _mesa_image_row_stride(pack, width, format, type);
 172
 173    /* For a window-system renderbuffer, the buffer is actually flipped
 174     * vertically, so we need to handle that.  Since the detiling function
 175     * can only really work in the forwards direction, we have to be a
 176     * little creative.  First, we compute the Y-offset of the first row of
 177     * the renderbuffer (in renderbuffer coordinates).  We then match that
 178     * with the last row of the client's data.  Finally, we give
 179     * tiled_to_linear a negative pitch so that it walks through the
 180     * client's data backwards as it walks through the renderbufer forwards.
 181     */
 182    if (rb->Name == 0) {
 183       yoffset = rb->Height - yoffset - height;
 184       pixels += (ptrdiff_t) (height - 1) * dst_pitch;
 185       dst_pitch = -dst_pitch;
 186    }
 187
 188    /* We postponed printing this message until having committed to executing
 189     * the function.
 190     */
 191    DBG("%s: x,y=(%d,%d) (w,h)=(%d,%d) format=0x%x type=0x%x "
 192        "mesa_format=0x%x tiling=%d "
 193        "pack=(alignment=%d row_length=%d skip_pixels=%d skip_rows=%d)\n",
 194        __func__, xoffset, yoffset, width, height,
 195        format, type, rb->Format, irb->mt->tiling,
 196        pack->Alignment, pack->RowLength, pack->SkipPixels,
 197        pack->SkipRows);
 198
 199    tiled_to_linear(
 200       xoffset * cpp, (xoffset + width) * cpp,
 201       yoffset, yoffset + height,
 202       pixels - (ptrdiff_t) yoffset * dst_pitch - (ptrdiff_t) xoffset * cpp,
 203       bo->virtual,
 204       dst_pitch, irb->mt->pitch,
 205       brw->has_swizzling,
 206       irb->mt->tiling,
 207       mem_copy
 208    );
 209
 210    drm_intel_bo_unmap(bo);
 211    return true;
 212 }
 213
 214 void
 215 intelReadPixels(struct gl_context * ctx,
 216                 GLint x, GLint y, GLsizei width, GLsizei height,
 217                 GLenum format, GLenum type,
 218                 const struct gl_pixelstore_attrib *pack, GLvoid * pixels)
 219 {
 220    bool ok;
 221
 222    struct brw_context *brw = brw_context(ctx);
 223    bool dirty;
 224
 225    DBG("%s\n", __func__);
 226
 227    if (_mesa_is_bufferobj(pack->BufferObj)) {
 228       if (_mesa_meta_pbo_GetTexSubImage(ctx, 2, NULL, x, y, 0, width, height, 1,
 229                                         format, type, pixels, pack))
 230          return;
 231
 232       perf_debug("%s: fallback to CPU mapping in PBO case\n", __func__);
 233    }
 234
 235    ok = intel_readpixels_tiled_memcpy(ctx, x, y, width, height,
 236                                       format, type, pixels, pack);
 237    if(ok)
 238       return;
 239
 240    /* glReadPixels() wont dirty the front buffer, so reset the dirty
 241     * flag after calling intel_prepare_render(). */
 242    dirty = brw->front_buffer_dirty;
 243    intel_prepare_render(brw);
 244    brw->front_buffer_dirty = dirty;
 245
 246    /* Update Mesa state before calling _mesa_readpixels().
 247     * XXX this may not be needed since ReadPixels no longer uses the
 248     * span code.
 249     */
 250
 251    if (ctx->NewState)
 252       _mesa_update_state(ctx);
 253
 254    _mesa_readpixels(ctx, x, y, width, height, format, type, pack, pixels);
 255
 256    /* There's an intel_prepare_render() call in intelSpanRenderStart(). */
 257    brw->front_buffer_dirty = dirty;
 258 }