only run shader on active fragments in the span

1 files changed, 3 insertions, 0 deletions

diff --git a/src/mesa/swrast/s_arbshader.c b/src/mesa/swrast/s_arbshader.c
index e17e799100e..c915b97d6ec 100644
--- a/src/mesa/swrast/s_arbshader.c
+++ b/src/mesa/swrast/s_arbshader.c
@@ -46,6 +46,8 @@ void _swrast_exec_arbshader (GLcontext *ctx, struct sw_span *span)
 

 	for (i = span->start; i < span->end; i++)

 	{

+            /* only run shader on active fragments */

+            if (span->array->mask[i]) {

 		GLfloat vec[4];

 		GLuint j;

 		GLboolean discard;

@@ -89,6 +91,7 @@ void _swrast_exec_arbshader (GLcontext *ctx, struct sw_span *span)
 			UNCLAMPED_FLOAT_TO_CHAN(span->array->rgba[i][BCOMP], vec[2]);

 			UNCLAMPED_FLOAT_TO_CHAN(span->array->rgba[i][ACOMP], vec[3]);

 		}

+            }

 	}

 }