i965: Add support for accelerated CopyTexSubImage.

There were hacks in EmitCopyBlit before to adjust offsets so that y=0 after
the offsets had been adjusted for a negative pitch.  It appears that those
hacks were due to an unclear and surprising aspect of the hardware: inverting
the pitch results in the blit into the specified rectangle being inverted,
without the user needing to adjust y and base offset.

Tested with piglit copytexsubimage test on 915GM and GM965.  Should fix
serious performance issues with ETQW and other applications.

1 files changed, 22 insertions, 16 deletions

diff --git a/src/mesa/drivers/dri/intel/intel_tex_copy.c b/src/mesa/drivers/dri/intel/intel_tex_copy.c
index f4cb4a781c..36446efde7 100644
--- a/src/mesa/drivers/dri/intel/intel_tex_copy.c
+++ b/src/mesa/drivers/dri/intel/intel_tex_copy.c
@@ -114,43 +114,49 @@ do_copy_texsubimage(struct intel_context *intel,
 
       if (_mesa_clip_to_region(fb->_Xmin, fb->_Ymin, fb->_Xmax, fb->_Ymax,
                                &x, &y, &width, &height)) {
+	 GLshort src_pitch;
+
          /* Update dst for clipped src.  Need to also clip the source rect.
           */
          dstx += x - orig_x;
          dsty += y - orig_y;
 
+	 /* image_offset may be non-page-aligned, but that's illegal for tiling.
+	  */
+	 assert(intelImage->mt->region->tiling == I915_TILING_NONE);
+
          if (ctx->ReadBuffer->Name == 0) {
             /* reading from a window, adjust x, y */
             __DRIdrawablePrivate *dPriv = intel->driDrawable;
-            GLuint window_y;
-            /* window_y = position of window on screen if y=0=bottom */
-            window_y = intel->intelScreen->height - (dPriv->y + dPriv->h);
-            y = window_y + y;
+	    y = dPriv->y + (dPriv->h - (y + height));
             x += dPriv->x;
+
+	    /* Invert the data coming from the source rectangle due to GL
+	     * and hardware disagreeing on where y=0 is.
+	     *
+	     * It appears that our offsets and pitches get mangled
+	     * appropriately by the hardware, and we don't need to adjust them
+	     * on our own.
+	     */
+	    src_pitch = -src->pitch;
          }
          else {
-            /* reading from a FBO */
-            /* invert Y */
-            y = ctx->ReadBuffer->Height - y - 1;
+            /* reading from a FBO, y is already oriented the way we like */
+	    src_pitch = src->pitch;
          }
 
-
-         /* A bit of fiddling to get the blitter to work with -ve
-          * pitches.  But we get a nice inverted blit this way, so it's
-          * worth it:
-          */
          intelEmitCopyBlit(intel,
                            intelImage->mt->cpp,
-                           -src->pitch,
+                           src_pitch,
                            src->buffer,
-                           src->height * src->pitch * src->cpp,
+                           0,
 			   src->tiling,
                            intelImage->mt->pitch,
                            intelImage->mt->region->buffer,
                            image_offset,
 			   intelImage->mt->region->tiling,
-                           x, y + height, dstx, dsty, width, height,
-			   GL_COPY); /* ? */
+                           x, y, dstx, dsty, width, height,
+			   GL_COPY);
       }
    }