[Mesa-stable] Fwd: [PATCH 1/2] mesa: Fix region overlap conditions for rectangles with a shared edge

[Anuj Phogat]

>From OpenGL 4.0 spec, section 4.3.2 "Copying Pixels":
"The pixels corresponding to these buffers are copied from the source
 rectangle bounded by the locations (srcX0, srcY 0) and (srcX1, srcY 1)
 to the destination rectangle bounded by the locations (dstX0, dstY 0)
 and (dstX1, dstY 1). The lower bounds of the rectangle are inclusive,
 while the upper bounds are exclusive."

So, the rectangles sharing just an edge shouldn't overlap.
     -----------
    |           |
     ------- ---
    |       |   |
    |       |   |
     ------- ---


Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle at amd.com>

---
 src/mesa/main/blit.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/mesa/main/blit.c b/src/mesa/main/blit.c
index a32f1a4..9c4c0f3 100644
--- a/src/mesa/main/blit.c
+++ b/src/mesa/main/blit.c
@@ -68,16 +68,16 @@ _mesa_regions_overlap(int srcX0, int srcY0,
                       int dstX0, int dstY0,
                       int dstX1, int dstY1)
 {
-   if (MAX2(srcX0, srcX1) < MIN2(dstX0, dstX1))
+   if (MAX2(srcX0, srcX1) <= MIN2(dstX0, dstX1))
       return false; /* dst completely right of src */

-   if (MAX2(dstX0, dstX1) < MIN2(srcX0, srcX1))
+   if (MAX2(dstX0, dstX1) <= MIN2(srcX0, srcX1))
       return false; /* dst completely left of src */

-   if (MAX2(srcY0, srcY1) < MIN2(dstY0, dstY1))
+   if (MAX2(srcY0, srcY1) <= MIN2(dstY0, dstY1))
       return false; /* dst completely above src */

-   if (MAX2(dstY0, dstY1) < MIN2(srcY0, srcY1))
+   if (MAX2(dstY0, dstY1) <= MIN2(srcY0, srcY1))
       return false; /* dst completely below src */

    return true; /* some overlap */
--
2.5.0