mesa: don't draw arrays if vertex position array is not enabled

For regular GL, we must have vertex positions in order to draw.  But ES2
doesn't have that requirement (positions can be computed from any array
of data).

See bug 19911.

1 files changed, 12 insertions, 3 deletions

diff --git a/src/mesa/main/api_validate.c b/src/mesa/main/api_validate.c
index 5c8955d7c8d..42d1e579e08 100644
--- a/src/mesa/main/api_validate.c
+++ b/src/mesa/main/api_validate.c
@@ -87,11 +87,20 @@ check_valid_to_render(GLcontext *ctx, char *function)
       return GL_FALSE;
    }
 
-   /* Always need vertex positions, unless a vertex program is in use */
-   if (!ctx->VertexProgram._Current &&
-       !ctx->Array.ArrayObj->Vertex.Enabled &&
+#if FEATURE_es2_glsl
+   /* For ES2, we can draw if any vertex array is enabled (and we should
+    * always have a vertex program/shader).
+    */
+   if (ctx->Array.ArrayObj->_Enabled == 0x0 || !ctx->VertexProgram._Current)
+      return GL_FALSE;
+#else
+   /* For regular OpenGL, only draw if we have vertex positions (regardless
+    * of whether or not we have a vertex program/shader).
+    */
+   if (!ctx->Array.ArrayObj->Vertex.Enabled &&
        !ctx->Array.ArrayObj->VertexAttrib[0].Enabled)
       return GL_FALSE;
+#endif
 
    return GL_TRUE;
 }