- for (i = 0; i < 3; i++) {
- vbuf->indices[vbuf->nr_indices++] = emit_vertex( vbuf, prim->v[i] );
+ if (vbuf->stage.draw->rasterizer->flatshade_first) {
+ /* Put provoking vertex in position expected by the driver.
+ * Emit last provoking vertex in first pos.
+ * Swap verts 0 & 1 to preserve polygon winding.
+ */
+ vbuf->indices[vbuf->nr_indices++] = emit_vertex( vbuf, prim->v[2] );
+ vbuf->indices[vbuf->nr_indices++] = emit_vertex( vbuf, prim->v[0] );
+ vbuf->indices[vbuf->nr_indices++] = emit_vertex( vbuf, prim->v[1] );
+ }
+ else {
+ for (i = 0; i < 3; i++) {
+ vbuf->indices[vbuf->nr_indices++] = emit_vertex( vbuf, prim->v[i] );
+ }