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-rw-r--r--src/mesa/state_tracker/st_atom_scissor.c17
1 files changed, 11 insertions, 6 deletions
diff --git a/src/mesa/state_tracker/st_atom_scissor.c b/src/mesa/state_tracker/st_atom_scissor.c
index 3fd59e1945..5e0c51cff0 100644
--- a/src/mesa/state_tracker/st_atom_scissor.c
+++ b/src/mesa/state_tracker/st_atom_scissor.c
@@ -31,6 +31,7 @@
*/
+#include "main/macros.h"
#include "st_context.h"
#include "pipe/p_context.h"
#include "st_atom.h"
@@ -52,15 +53,19 @@ update_scissor( struct st_context *st )
scissor.maxy = fb->Height;
if (st->ctx->Scissor.Enabled) {
- if ((GLuint)st->ctx->Scissor.X > scissor.minx)
+ /* need to be careful here with xmax or ymax < 0 */
+ GLint xmax = MAX2(0, st->ctx->Scissor.X + st->ctx->Scissor.Width);
+ GLint ymax = MAX2(0, st->ctx->Scissor.Y + st->ctx->Scissor.Height);
+
+ if (st->ctx->Scissor.X > (GLint)scissor.minx)
scissor.minx = st->ctx->Scissor.X;
- if ((GLuint)st->ctx->Scissor.Y > scissor.miny)
+ if (st->ctx->Scissor.Y > (GLint)scissor.miny)
scissor.miny = st->ctx->Scissor.Y;
- if ((GLuint)st->ctx->Scissor.X + st->ctx->Scissor.Width < scissor.maxx)
- scissor.maxx = st->ctx->Scissor.X + st->ctx->Scissor.Width;
- if ((GLuint)st->ctx->Scissor.Y + st->ctx->Scissor.Height < scissor.maxy)
- scissor.maxy = st->ctx->Scissor.Y + st->ctx->Scissor.Height;
+ if (xmax < (GLint) scissor.maxx)
+ scissor.maxx = xmax;
+ if (ymax < (GLint) scissor.maxy)
+ scissor.maxy = ymax;
/* check for null space */
if (scissor.minx >= scissor.maxx || scissor.miny >= scissor.maxy)