1 files changed, 2 insertions, 1 deletions

diff --git a/linden/indra/newview/llsurfacepatch.cpp b/linden/indra/newview/llsurfacepatch.cpp
index 5b03c98..42aea9e 100644
--- a/linden/indra/newview/llsurfacepatch.cpp
+++ b/linden/indra/newview/llsurfacepatch.cpp
@@ -206,10 +206,11 @@ LLVector2 LLSurfacePatch::getTexCoords(const U32 x, const U32 y) const
 void LLSurfacePatch::eval(const U32 x, const U32 y, const U32 stride, LLVector3 *vertex, LLVector3 *normal,
                                                   LLVector2 *tex0, LLVector2 *tex1)
 {
-        if (!mSurfacep || !mSurfacep->getRegion())
+        if (!mSurfacep || !mSurfacep->getRegion() || !mSurfacep->getGridsPerEdge())
         {
                 return; // failsafe
         }
+        llassert_always(vertex && normal && tex0 && tex1);
         
         U32 surface_stride = mSurfacep->getGridsPerEdge();
         U32 point_offset = x + y*surface_stride;