Mesa (master): mesa: Correct _mesa_clip_to_region() off-by-one.

[Eric Anholt]

Module: Mesa
Branch: master
Commit: aa09e0a1d532d0de2e094957d0509a7f60ebeafa
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=aa09e0a1d532d0de2e094957d0509a7f60ebeafa

Author: Eric Anholt <eric at anholt.net>
Date:   Thu Dec 18 18:23:51 2008 -0800

mesa: Correct _mesa_clip_to_region() off-by-one.

Note how if:
x + width == xmax + 0: width -= 0
x + width == xmax + 1: width -= 0
x + width == xmax + 2: width -= 1

So, the function was clipping to [xmin, xmax+1), not [xmin, xmax) like it was
supposed to.  Same for ymax.

---

 src/mesa/main/image.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/mesa/main/image.c b/src/mesa/main/image.c
index 4551b4a..6b19fc8 100644
--- a/src/mesa/main/image.c
+++ b/src/mesa/main/image.c
@@ -5152,7 +5152,7 @@ _mesa_clip_to_region(GLint xmin, GLint ymin,
 
    /* right clipping */
    if (*x + *width > xmax)
-      *width -= (*x + *width - xmax - 1);
+      *width -= (*x + *width - xmax);
 
    if (*width <= 0)
       return GL_FALSE;
@@ -5165,7 +5165,7 @@ _mesa_clip_to_region(GLint xmin, GLint ymin,
 
    /* top (or bottom) clipping */
    if (*y + *height > ymax)
-      *height -= (*y + *height - ymax - 1);
+      *height -= (*y + *height - ymax);
 
    if (*height <= 0)
       return GL_FALSE;