+#if FEATURE_ES1
+ case API_OPENGLES:
+ /* For OpenGL ES, only draw if we have vertex positions
+ */
+ if (!ctx->Array.ArrayObj->Vertex.Enabled)
+ return GL_FALSE;
+ break;
+#endif
+
+#if FEATURE_GL
+ case API_OPENGL:
+ {
+ const struct gl_shader_program *vsProg =
+ ctx->Shader.CurrentVertexProgram;
+ GLboolean haveVertexShader = (vsProg && vsProg->LinkStatus);
+ GLboolean haveVertexProgram = ctx->VertexProgram._Enabled;
+ if (haveVertexShader || haveVertexProgram) {
+ /* Draw regardless of whether or not we have any vertex arrays.
+ * (Ex: could draw a point using a constant vertex pos)
+ */
+ return GL_TRUE;
+ }
+ else {
+ /* Draw if we have vertex positions (GL_VERTEX_ARRAY or generic
+ * array [0]).
+ */
+ return (ctx->Array.ArrayObj->Vertex.Enabled ||
+ ctx->Array.ArrayObj->VertexAttrib[0].Enabled);
+ }
+ }
+ break;
+#endif
+
+ default:
+ ASSERT_NO_FEATURE();
+ }
+