From a887a44b2da48dfa50b5c19c2be9ebbef79ae2db Mon Sep 17 00:00:00 2001
From: Keith Whitwell <keith@tungstengraphics.com>
Date: Mon, 10 Jan 2005 12:30:08 +0000
Subject: [PATCH] Fix segfault in pipes by dealing with stride == 0 case in
 generic_interp_extras

---
 src/mesa/tnl/t_vertex.c | 39 +++++++++++++++++++++++++--------------
 1 file changed, 25 insertions(+), 14 deletions(-)

diff --git a/src/mesa/tnl/t_vertex.c b/src/mesa/tnl/t_vertex.c
index e88df0707f1..2ed4c417590 100644
--- a/src/mesa/tnl/t_vertex.c
+++ b/src/mesa/tnl/t_vertex.c
@@ -1031,22 +1031,30 @@ static void generic_interp_extras( GLcontext *ctx,
 {
    struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
 
-   if (VB->ColorPtr[1]) {
+   /* If stride is zero, ColorPtr[1] is constant across the VB, so
+    * there is no point interpolating between two values as they will
+    * be identical.  In all other cases, this value is generated by
+    * t_vb_lighttmp.h and has a stride of 4 dwords.
+    */
+   if (VB->ColorPtr[1] && VB->ColorPtr[1]->stride) {
       assert(VB->ColorPtr[1]->stride == 4 * sizeof(GLfloat));
 
       INTERP_4F( t,
 		 VB->ColorPtr[1]->data[dst],
 		 VB->ColorPtr[1]->data[out],
 		 VB->ColorPtr[1]->data[in] );
+   }
 
-      if (VB->SecondaryColorPtr[1]) {
-	 INTERP_3F( t,
-		    VB->SecondaryColorPtr[1]->data[dst],
-		    VB->SecondaryColorPtr[1]->data[out],
-		    VB->SecondaryColorPtr[1]->data[in] );
-      }
+   if (VB->SecondaryColorPtr[1]) {
+      assert(VB->SecondaryColorPtr[1]->stride == 4 * sizeof(GLfloat));
+      
+      INTERP_3F( t,
+		 VB->SecondaryColorPtr[1]->data[dst],
+		 VB->SecondaryColorPtr[1]->data[out],
+		 VB->SecondaryColorPtr[1]->data[in] );
    }
-   else if (VB->IndexPtr[1]) {
+   
+   if (VB->IndexPtr[1]) {
       VB->IndexPtr[1]->data[dst][0] = LINTERP( t,
 					       VB->IndexPtr[1]->data[out][0],
 					       VB->IndexPtr[1]->data[in][0] );
@@ -1064,16 +1072,19 @@ static void generic_copy_pv_extras( GLcontext *ctx,
 {
    struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
 
-   if (VB->ColorPtr[1]) {
+   /* See above comment:
+    */
+   if (VB->ColorPtr[1] && VB->ColorPtr[1]->stride) {
       COPY_4FV( VB->ColorPtr[1]->data[dst], 
 		VB->ColorPtr[1]->data[src] );
+   }
 
-      if (VB->SecondaryColorPtr[1]) {
-	 COPY_4FV( VB->SecondaryColorPtr[1]->data[dst], 
-		   VB->SecondaryColorPtr[1]->data[src] );
-      }
+   if (VB->SecondaryColorPtr[1]) {
+      COPY_4FV( VB->SecondaryColorPtr[1]->data[dst], 
+		VB->SecondaryColorPtr[1]->data[src] );
    }
-   else if (VB->IndexPtr[1]) {
+
+   if (VB->IndexPtr[1]) {
       VB->IndexPtr[1]->data[dst][0] = VB->IndexPtr[1]->data[src][0];
    }
 
-- 
2.30.2