mesa: add/update comments in _mesa_copy_buffer_subdata()

[mesa.git] / src / mesa / drivers / dri / intel / intel_pixel_copy.c

/**************************************************************************
 * 
 * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
 * 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 TUNGSTEN GRAPHICS 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 "main/glheader.h"
#include "main/image.h"
#include "main/state.h"
#include "main/mtypes.h"
#include "main/condrender.h"
#include "drivers/common/meta.h"

#include "intel_context.h"
#include "intel_buffers.h"
#include "intel_mipmap_tree.h"
#include "intel_regions.h"
#include "intel_pixel.h"
#include "intel_fbo.h"

#define FILE_DEBUG_FLAG DEBUG_PIXEL

/**
 * Check if any fragment operations are in effect which might effect
 * glCopyPixels.  Differs from intel_check_blit_fragment_ops in that
 * we allow Scissor.
 */
static bool
intel_check_copypixel_blit_fragment_ops(struct gl_context * ctx)
{
   if (ctx->NewState)
      _mesa_update_state(ctx);

   /* Could do logicop with the blitter: 
    */
   return !(ctx->_ImageTransferState ||
            ctx->Color.AlphaEnabled ||
            ctx->Depth.Test ||
            ctx->Fog.Enabled ||
            ctx->Stencil._Enabled ||
            !ctx->Color.ColorMask[0][0] ||
            !ctx->Color.ColorMask[0][1] ||
            !ctx->Color.ColorMask[0][2] ||
            !ctx->Color.ColorMask[0][3] ||
            ctx->Texture._EnabledUnits ||
            ctx->FragmentProgram._Enabled ||
            ctx->Color.BlendEnabled);
}


/**
 * CopyPixels with the blitter.  Don't support zooming, pixel transfer, etc.
 */
static bool
do_blit_copypixels(struct gl_context * ctx,
                   GLint srcx, GLint srcy,
                   GLsizei width, GLsizei height,
                   GLint dstx, GLint dsty, GLenum type)
{
   struct intel_context *intel = intel_context(ctx);
   struct gl_framebuffer *fb = ctx->DrawBuffer;
   struct gl_framebuffer *read_fb = ctx->ReadBuffer;
   GLint orig_dstx;
   GLint orig_dsty;
   GLint orig_srcx;
   GLint orig_srcy;
   bool flip = false;
   struct intel_renderbuffer *draw_irb = NULL;
   struct intel_renderbuffer *read_irb = NULL;

   /* Update draw buffer bounds */
   _mesa_update_state(ctx);

   switch (type) {
   case GL_COLOR:
      if (fb->_NumColorDrawBuffers != 1) {
         fallback_debug("glCopyPixels() fallback: MRT\n");
         return false;
      }

      draw_irb = intel_renderbuffer(fb->_ColorDrawBuffers[0]);
      read_irb = intel_renderbuffer(read_fb->_ColorReadBuffer);
      break;
   case GL_DEPTH_STENCIL_EXT:
      draw_irb = intel_renderbuffer(fb->Attachment[BUFFER_DEPTH].Renderbuffer);
      read_irb =
         intel_renderbuffer(read_fb->Attachment[BUFFER_DEPTH].Renderbuffer);
      break;
   case GL_DEPTH:
      fallback_debug("glCopyPixels() fallback: GL_DEPTH\n");
      return false;
   case GL_STENCIL:
      fallback_debug("glCopyPixels() fallback: GL_STENCIL\n");
      return false;
   default:
      fallback_debug("glCopyPixels(): Unknown type\n");
      return false;
   }

   if (!draw_irb) {
      fallback_debug("glCopyPixels() fallback: missing draw buffer\n");
      return false;
   }

   if (!read_irb) {
      fallback_debug("glCopyPixels() fallback: missing read buffer\n");
      return false;
   }

   if (draw_irb->Base.Format != read_irb->Base.Format &&
       !(draw_irb->Base.Format == MESA_FORMAT_XRGB8888 &&
         read_irb->Base.Format == MESA_FORMAT_ARGB8888)) {
      fallback_debug("glCopyPixels() fallback: mismatched formats (%s -> %s\n",
                     _mesa_get_format_name(read_irb->Base.Format),
                     _mesa_get_format_name(draw_irb->Base.Format));
      return false;
   }

   /* Copypixels can be more than a straight copy.  Ensure all the
    * extra operations are disabled:
    */
   if (!intel_check_copypixel_blit_fragment_ops(ctx) ||
       ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F)
      return false;

   intel_prepare_render(intel);

   intel_flush(&intel->ctx);

   /* Clip to destination buffer. */
   orig_dstx = dstx;
   orig_dsty = dsty;
   if (!_mesa_clip_to_region(fb->_Xmin, fb->_Ymin,
                             fb->_Xmax, fb->_Ymax,
                             &dstx, &dsty, &width, &height))
      goto out;
   /* Adjust src coords for our post-clipped destination origin */
   srcx += dstx - orig_dstx;
   srcy += dsty - orig_dsty;

   /* Clip to source buffer. */
   orig_srcx = srcx;
   orig_srcy = srcy;
   if (!_mesa_clip_to_region(0, 0,
                             read_fb->Width, read_fb->Height,
                             &srcx, &srcy, &width, &height))
      goto out;
   /* Adjust dst coords for our post-clipped source origin */
   dstx += srcx - orig_srcx;
   dsty += srcy - orig_srcy;

   /* Flip dest Y if it's a window system framebuffer. */
   if (fb->Name == 0) {
      /* copypixels to a window system framebuffer */
      dsty = fb->Height - dsty - height;
      flip = !flip;
   }

   /* Flip source Y if it's a window system framebuffer. */
   if (read_fb->Name == 0) {
      srcy = read_fb->Height - srcy - height;
      flip = !flip;
   }

   srcx += read_irb->draw_x;
   srcy += read_irb->draw_y;
   dstx += draw_irb->draw_x;
   dsty += draw_irb->draw_y;

   if (!intel_region_copy(intel,
                          draw_irb->mt->region, 0, dstx, dsty,
                          read_irb->mt->region, 0, srcx, srcy,
                          width, height, flip,
                          ctx->Color.ColorLogicOpEnabled ?
                          ctx->Color.LogicOp : GL_COPY)) {
      DBG("%s: blit failure\n", __FUNCTION__);
      return false;
   }

out:
   intel_check_front_buffer_rendering(intel);

   DBG("%s: success\n", __FUNCTION__);
   return true;
}


void
intelCopyPixels(struct gl_context * ctx,
                GLint srcx, GLint srcy,
                GLsizei width, GLsizei height,
                GLint destx, GLint desty, GLenum type)
{
   DBG("%s\n", __FUNCTION__);

   if (!_mesa_check_conditional_render(ctx))
      return;

   if (do_blit_copypixels(ctx, srcx, srcy, width, height, destx, desty, type))
      return;

   /* this will use swrast if needed */
   _mesa_meta_CopyPixels(ctx, srcx, srcy, width, height, destx, desty, type);
}