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Diffstat (limited to 'src/mesa/swrast/s_triangle.c')
-rw-r--r--src/mesa/swrast/s_triangle.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/src/mesa/swrast/s_triangle.c b/src/mesa/swrast/s_triangle.c
index 9260e35066..1d2fed7169 100644
--- a/src/mesa/swrast/s_triangle.c
+++ b/src/mesa/swrast/s_triangle.c
@@ -44,8 +44,9 @@
#include "s_triangle.h"
-/*
- * Just used for feedback mode.
+/**
+ * Test if a triangle should be culled. Used for feedback and selection mode.
+ * \return GL_TRUE if the triangle is to be culled, GL_FALSE otherwise.
*/
GLboolean
_swrast_culltriangle( GLcontext *ctx,
@@ -53,16 +54,17 @@ _swrast_culltriangle( GLcontext *ctx,
const SWvertex *v1,
const SWvertex *v2 )
{
+ SWcontext *swrast = SWRAST_CONTEXT(ctx);
GLfloat ex = v1->attrib[FRAG_ATTRIB_WPOS][0] - v0->attrib[FRAG_ATTRIB_WPOS][0];
GLfloat ey = v1->attrib[FRAG_ATTRIB_WPOS][1] - v0->attrib[FRAG_ATTRIB_WPOS][1];
GLfloat fx = v2->attrib[FRAG_ATTRIB_WPOS][0] - v0->attrib[FRAG_ATTRIB_WPOS][0];
GLfloat fy = v2->attrib[FRAG_ATTRIB_WPOS][1] - v0->attrib[FRAG_ATTRIB_WPOS][1];
GLfloat c = ex*fy-ey*fx;
- if (c * SWRAST_CONTEXT(ctx)->_BackfaceCullSign > 0)
- return 0;
+ if (c * swrast->_BackfaceSign * swrast->_BackfaceCullSign < 0.0F)
+ return GL_FALSE;
- return 1;
+ return GL_TRUE;
}