From: Ville Syrjälä <ville.syrj...@linux.intel.com>
When drawing quads using triangles we need to be careful to make
the provoking vertices match when flat shading.
v2: Major rebase on top of Ian other t_dd_dmatmp.h work.
Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com>
Signed-off-by: Ian Romanick <ian.d.roman...@intel.com>
---
src/mesa/tnl_dd/t_dd_dmatmp.h | 46 ++++++++++++++++++++++++-------------------
1 file changed, 26 insertions(+), 20 deletions(-)
diff --git a/src/mesa/tnl_dd/t_dd_dmatmp.h b/src/mesa/tnl_dd/t_dd_dmatmp.h
index 9a6f6c82..23746d5 100644
--- a/src/mesa/tnl_dd/t_dd_dmatmp.h
+++ b/src/mesa/tnl_dd/t_dd_dmatmp.h
@@ -367,28 +367,33 @@ static void TAG(render_quads_verts)(struct gl_context
*ctx,
GLuint count,
GLuint flags)
{
- LOCAL_VARS;
- GLuint j;
-
- /* Emit whole number of quads in total. */
- count -= count & 3;
+ if (ctx->Light.ShadeModel == GL_SMOOTH ||
+ ctx->Light.ProvokingVertex == GL_LAST_VERTEX_CONVENTION) {
+ LOCAL_VARS;
+ GLuint j;
- /* Hardware doesn't have a quad primitive type -- try to simulate it using
- * triangle primitive. This is a win for gears, but is it useful in the
- * broader world?
- */
- INIT(GL_TRIANGLES);
+ /* Emit whole number of quads in total. */
+ count -= count & 3;
- for (j = 0; j + 3 < count; j += 4) {
- void *tmp = ALLOC_VERTS(6);
- /* Send v0, v1, v3
- */
- tmp = EMIT_VERTS(ctx, start + j, 2, tmp);
- tmp = EMIT_VERTS(ctx, start + j + 3, 1, tmp);
- /* Send v1, v2, v3
+ /* Hardware doesn't have a quad primitive type -- try to simulate it
using
+ * triangle primitive. This is a win for gears, but is it useful in the
+ * broader world?
*/
- tmp = EMIT_VERTS(ctx, start + j + 1, 3, tmp);
- (void) tmp;
+ INIT(GL_TRIANGLES);
+
+ for (j = 0; j + 3 < count; j += 4) {
+ void *tmp = ALLOC_VERTS(6);
+ /* Send v0, v1, v3
+ */
+ tmp = EMIT_VERTS(ctx, start + j, 2, tmp);
+ tmp = EMIT_VERTS(ctx, start + j + 3, 1, tmp);
+ /* Send v1, v2, v3
+ */
+ tmp = EMIT_VERTS(ctx, start + j + 1, 3, tmp);
+ (void) tmp;
+ }
+ } else {
+ unreachable("Cannot draw primitive");
}
}
@@ -462,7 +467,8 @@ static bool TAG(validate_render)(struct gl_context *ctx,
ok = VB->Elts || ctx->Light.ShadeModel == GL_SMOOTH;
break;
case GL_QUADS:
- ok = true; /* flatshading is ok. */
+ ok = ctx->Light.ShadeModel == GL_SMOOTH ||
+ ctx->Light.ProvokingVertex == GL_LAST_VERTEX_CONVENTION;
break;
default:
break;
--
2.1.0
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