[Mesa-dev] [PATCH] i965: Fix haswell_upload_cut_index when there's no index buffer.

[Kenneth Graunke]

brw->ib.type is reset to -1 at the start of each batch.  If there's no
index buffer, it won't get updated to a sensible value, resulting in
_mesa_primitive_restart_index's "Invalid index buffer type" assertion
tripping.

Fixes a regression since 7c87a3b5dac118697a9b67caa7b6d5cab60f316d.

NOTE: This is a candidate for the 9.1 branch (and should be squashed).

Cc: Eric Anholt <eric at anholt.net>
Cc: Ian Romanick <idr at freedesktop.org>
Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
 src/mesa/drivers/dri/i965/brw_primitive_restart.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/mesa/drivers/dri/i965/brw_primitive_restart.c b/src/mesa/drivers/dri/i965/brw_primitive_restart.c
index e926538..b5cfbbc 100644
--- a/src/mesa/drivers/dri/i965/brw_primitive_restart.c
+++ b/src/mesa/drivers/dri/i965/brw_primitive_restart.c
@@ -194,9 +194,21 @@ haswell_upload_cut_index(struct brw_context *brw)
       ctx->Array._PrimitiveRestart ? HSW_CUT_INDEX_ENABLE : 0;
 
    /* BRW_NEW_INDEX_BUFFER */
+   unsigned cut_index;
+   if (brw->ib.ib) {
+      cut_index = _mesa_primitive_restart_index(ctx, brw->ib.type);
+   } else {
+      /* There's no index buffer, but primitive restart may still apply
+       * to glDrawArrays and such.  FIXED_INDEX mode only applies to drawing
+       * operations that use an index buffer, so we can ignore it and use
+       * the GL restart index directly.
+       */
+      cut_index = ctx->Array.RestartIndex;
+   }
+
    BEGIN_BATCH(2);
    OUT_BATCH(_3DSTATE_VF << 16 | cut_index_setting | (2 - 2));
-   OUT_BATCH(_mesa_primitive_restart_index(ctx, brw->ib.type));
+   OUT_BATCH(cut_index);
    ADVANCE_BATCH();
 }
 
-- 
1.8.2.2