[Mesa-dev] [PATCH 2/2] gallium: Fix region overlap conditions for rectangles with a shared edge

[Nicolai Hähnle]

For the series:

Reviewed-by: Nicolai Hähnle <nicolai.haehnle at amd.com>

On 11.12.2015 23:41, Anuj Phogat wrote:
>  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.
>   -----------
> |           |
>   ------- ---
> |       |   |
> |       |   |
>   ------- ---
>
> Cc: Ian Romanick <ian.d.romanick at intel.com>
> Cc: Matt Turner <mattst88 at gmail.com>
> Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
> ---
>   src/gallium/auxiliary/util/u_blit.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/src/gallium/auxiliary/util/u_blit.c b/src/gallium/auxiliary/util/u_blit.c
> index 9737c94..f45a1b8 100644
> --- a/src/gallium/auxiliary/util/u_blit.c
> +++ b/src/gallium/auxiliary/util/u_blit.c
> @@ -314,16 +314,16 @@ 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; /* src completely left of dst */
>
> -   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; /* src completely above dst */
>
> -   if (MAX2(dstY0, dstY1) < MIN2(srcY0, srcY1))
> +   if (MAX2(dstY0, dstY1) <= MIN2(srcY0, srcY1))
>         return FALSE; /* dst completely above src */
>
>      return TRUE; /* some overlap */
>