st/mesa: only set primitive_restart when the restart index is in range

Even when enabled, primitive restart has no effect when the restart index
is larger than the representable values in the index buffer.

Fixes GL45-CTS.gtf31.GL3Tests.primitive_restart.primitive_restart_upconvert
for radeonsi VI.

v2: add an explanatory comment

Cc: "12.0 13.0" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Marek Olšák <marek.olsak@amd.com> (v1)
This commit is contained in:
Nicolai Hähnle 2016-10-19 18:14:48 +02:00
parent 3d9b57e493
commit bfa50f88ce

View file

@ -205,8 +205,19 @@ st_draw_vbo(struct gl_context *ctx,
/* The VBO module handles restart for the non-indexed GLDrawArrays
* so we only set these fields for indexed drawing:
*/
info.primitive_restart = ctx->Array._PrimitiveRestart;
info.restart_index = _mesa_primitive_restart_index(ctx, ib->type);
if (ctx->Array._PrimitiveRestart) {
info.restart_index = _mesa_primitive_restart_index(ctx, ib->type);
/* Enable primitive restart only when the restart index can have an
* effect. This is required for correctness in radeonsi VI support,
* though other hardware may also benefit from taking a faster,
* non-restart path when possible.
*/
if ((ibuffer.index_size >= 4) ||
(ibuffer.index_size >= 2 && info.restart_index <= 0xffff) ||
(info.restart_index <= 0xff))
info.primitive_restart = true;
}
}
else {
/* Transform feedback drawing is always non-indexed. */