1 files changed, 64 insertions, 16 deletions

diff --git a/src/gallium/auxiliary/util/u_blit.c b/src/gallium/auxiliary/util/u_blit.c
index 414cf910254..f7cc7dd3759 100644
--- a/src/gallium/auxiliary/util/u_blit.c
+++ b/src/gallium/auxiliary/util/u_blit.c
@@ -155,7 +155,11 @@ util_destroy_blit(struct blit_state *ctx)
 }
 
 
-static unsigned get_next_slot( struct blit_state *ctx )
+/**
+ * Get offset of next free slot in vertex buffer for quad vertices.
+ */
+static unsigned
+get_next_slot( struct blit_state *ctx )
 {
    const unsigned max_slots = 4096 / sizeof ctx->vertices;
 
@@ -173,7 +177,6 @@ static unsigned get_next_slot( struct blit_state *ctx )
 }
                                
 
-
 /**
  * Setup vertex data for the textured quad we'll draw.
  * Note: y=0=top
@@ -260,9 +263,38 @@ setup_vertex_data_tex(struct blit_state *ctx,
 
    return offset;
 }
+
+
+/**
+ * \return TRUE if two regions overlap, FALSE otherwise
+ */
+static boolean
+regions_overlap(int srcX0, int srcY0,
+                int srcX1, int srcY1,
+                int dstX0, int dstY0,
+                int dstX1, int dstY1)
+{
+   if (MAX2(srcX0, srcX1) < MIN2(dstX0, dstX1))
+      return FALSE; /* src completely left of dst */
+
+   if (MAX2(dstX0, dstX1) < MIN2(srcX0, srcX1))
+      return FALSE; /* dst completely left of src */
+
+   if (MAX2(srcY0, srcY1) < MIN2(dstY0, dstY1))
+      return FALSE; /* src completely above dst */
+
+   if (MAX2(dstY0, dstY1) < MIN2(srcY0, srcY1))
+      return FALSE; /* dst completely above src */
+
+   return TRUE; /* some overlap */
+}
+
+
 /**
  * Copy pixel block from src surface to dst surface.
  * Overlapping regions are acceptable.
+ * Flipping and stretching are supported.
+ * XXX what about clipping???
  * XXX need some control over blitting Z and/or stencil.
  */
 void
@@ -285,10 +317,40 @@ util_blit_pixels(struct blit_state *ctx,
    const int srcLeft = MIN2(srcX0, srcX1);
    const int srcTop = MIN2(srcY0, srcY1);
    unsigned offset;
+   boolean overlap;
 
    assert(filter == PIPE_TEX_MIPFILTER_NEAREST ||
           filter == PIPE_TEX_MIPFILTER_LINEAR);
 
+   assert(screen->is_format_supported(screen, src->format, PIPE_TEXTURE_2D,
+                                      PIPE_TEXTURE_USAGE_SAMPLER, 0));
+   assert(screen->is_format_supported(screen, dst->format, PIPE_TEXTURE_2D,
+                                      PIPE_TEXTURE_USAGE_SAMPLER, 0));
+
+   /* do the regions overlap? */
+   overlap = (src == dst) && regions_overlap(srcX0, srcY0, srcX1, srcY1,
+                                             dstX0, dstY0, dstX1, dstY1);
+
+   /*
+    * Check for simple case:  no format conversion, no flipping, no stretching,
+    * no overlapping.
+    */
+   if (dst->format == src->format &&
+       srcX0 < srcX1 &&
+       dstX0 < dstX1 &&
+       srcY0 < srcY1 &&
+       dstY0 < dstY1 &&
+       (dstX1 - dstX0) == (srcX1 - srcX0) &&
+       (dstY1 - dstY0) == (srcY1 - srcY0) &&
+       !overlap) {
+      /* FIXME: this will most surely fail for overlapping rectangles */
+      pipe->surface_copy(pipe,
+			 dst, dstX0, dstY0, /* dest */
+			 src, srcX0, srcY0, /* src */
+			 srcW, srcH);       /* size */
+      return;
+   }
+   
    if (srcLeft != srcX0) {
       /* left-right flip */
       int tmp = dstX0;
@@ -303,20 +365,6 @@ util_blit_pixels(struct blit_state *ctx,
       dstY1 = tmp;
    }
 
-   assert(screen->is_format_supported(screen, src->format, PIPE_TEXTURE_2D,
-                                      PIPE_TEXTURE_USAGE_SAMPLER, 0));
-   assert(screen->is_format_supported(screen, dst->format, PIPE_TEXTURE_2D,
-                                      PIPE_TEXTURE_USAGE_SAMPLER, 0));
-
-   if(dst->format == src->format && (dstX1 - dstX0) == srcW && (dstY1 - dstY0) == srcH) {
-      /* FIXME: this will most surely fail for overlapping rectangles */
-      pipe->surface_copy(pipe,
-			 dst, dstX0, dstY0,   /* dest */
-			 src, srcX0, srcY0, /* src */
-			 srcW, srcH);     /* size */
-      return;
-   }
-   
    assert(screen->is_format_supported(screen, dst->format, PIPE_TEXTURE_2D,
                                       PIPE_TEXTURE_USAGE_RENDER_TARGET, 0));