vc4: Just stream out fallback IB contents.

The idea I had when I wrote the original shadow code was that you'd see a
set_index_buffer to the IB, then a bunch of draws out of it.  What's
actually happening in openarena is that set_index_buffer occurs at every
draw, so we end up making a new shadow BO every time, and converting more
of the BO than is actually used in the draw.

While I could maybe come up with a better caching scheme, for now just
do the simple thing that doesn't result in a new shadow IB allocation
per draw.

Improves performance of isosurf in drawelements mode by 58.7967% +/-
3.86152% (n=8).

1 files changed, 2 insertions, 18 deletions

diff --git a/src/gallium/drivers/vc4/vc4_state.c b/src/gallium/drivers/vc4/vc4_state.c
index 7875eff0325..4a1d4c3a4d6 100644
--- a/src/gallium/drivers/vc4/vc4_state.c
+++ b/src/gallium/drivers/vc4/vc4_state.c
@@ -304,24 +304,8 @@ vc4_set_index_buffer(struct pipe_context *pctx,
 
         if (ib) {
                 assert(!ib->user_buffer);
-
-                if (ib->index_size == 4) {
-                        struct pipe_resource tmpl = *ib->buffer;
-                        assert(tmpl.format == PIPE_FORMAT_R8_UNORM);
-                        assert(tmpl.height0 == 1);
-                        tmpl.width0 = (tmpl.width0 - ib->offset) / 2;
-                        struct pipe_resource *pshadow =
-                                vc4_resource_create(&vc4->screen->base, &tmpl);
-                        struct vc4_resource *shadow = vc4_resource(pshadow);
-                        pipe_resource_reference(&shadow->shadow_parent, ib->buffer);
-
-                        pipe_resource_reference(&vc4->indexbuf.buffer, NULL);
-                        vc4->indexbuf.buffer = pshadow;
-                        vc4->indexbuf.index_size = 2;
-                } else {
-                        pipe_resource_reference(&vc4->indexbuf.buffer, ib->buffer);
-                        vc4->indexbuf.index_size = ib->index_size;
-                }
+                pipe_resource_reference(&vc4->indexbuf.buffer, ib->buffer);
+                vc4->indexbuf.index_size = ib->index_size;
                 vc4->indexbuf.offset = ib->offset;
         } else {
                 pipe_resource_reference(&vc4->indexbuf.buffer, NULL);