nouveau: nv10: also check ctx->DrawBuffer in nv10ViewportScale

diff --git a/src/mesa/drivers/dri/nouveau/nv10_state.c b/src/mesa/drivers/dri/nouveau/nv10_state.c
index 09fc075..e204eba 100644 (file)
--- a/src/mesa/drivers/dri/nouveau/nv10_state.c
+++ b/src/mesa/drivers/dri/nouveau/nv10_state.c
@@ -41,13 +41,18 @@ static void nv10ViewportScale(nouveauContextPtr nmesa)
        GLuint h = ctx->Viewport.Height;
 
        GLfloat max_depth = (ctx->Viewport.Near + ctx->Viewport.Far) * 0.5;
-       switch (ctx->DrawBuffer->_DepthBuffer->DepthBits) {
-               case 16:
-                       max_depth *= 32767.0;
-                       break;
-               case 24:
-                       max_depth *= 16777215.0;
-                       break;
+       if (ctx->DrawBuffer) {
+               switch (ctx->DrawBuffer->_DepthBuffer->DepthBits) {
+                       case 16:
+                               max_depth *= 32767.0;
+                               break;
+                       case 24:
+                               max_depth *= 16777215.0;
+                               break;
+               }
+       } else {
+               /* Default to 24 bits range */  
+               max_depth *= 16777215.0;
        }
 
        BEGIN_RING_CACHE(NvSub3D, NV10_TCL_PRIMITIVE_3D_VIEWPORT_SCALE_X, 4);