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-rw-r--r--src/mesa/drivers/dri/i965/brw_draw_upload.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_draw_upload.c b/src/mesa/drivers/dri/i965/brw_draw_upload.c
index c1fe85908b..e7a87b6e09 100644
--- a/src/mesa/drivers/dri/i965/brw_draw_upload.c
+++ b/src/mesa/drivers/dri/i965/brw_draw_upload.c
@@ -479,6 +479,28 @@ static void brw_emit_vertices(struct brw_context *brw)
brw_emit_query_begin(brw);
+ /* If the VS doesn't read any inputs (calculating vertex position from
+ * a state variable for some reason, for example), emit a single pad
+ * VERTEX_ELEMENT struct and bail.
+ *
+ * The stale VB state stays in place, but they don't do anything unless
+ * a VE loads from them.
+ */
+ if (brw->vb.nr_enabled == 0) {
+ BEGIN_BATCH(3, IGNORE_CLIPRECTS);
+ OUT_BATCH((CMD_VERTEX_ELEMENT << 16) | 1);
+ OUT_BATCH((0 << BRW_VE0_INDEX_SHIFT) |
+ BRW_VE0_VALID |
+ (BRW_SURFACEFORMAT_R32G32B32A32_FLOAT << BRW_VE0_FORMAT_SHIFT) |
+ (0 << BRW_VE0_SRC_OFFSET_SHIFT));
+ OUT_BATCH((BRW_VE1_COMPONENT_STORE_0 << BRW_VE1_COMPONENT_0_SHIFT) |
+ (BRW_VE1_COMPONENT_STORE_0 << BRW_VE1_COMPONENT_1_SHIFT) |
+ (BRW_VE1_COMPONENT_STORE_0 << BRW_VE1_COMPONENT_2_SHIFT) |
+ (BRW_VE1_COMPONENT_STORE_1_FLT << BRW_VE1_COMPONENT_3_SHIFT));
+ ADVANCE_BATCH();
+ return;
+ }
+
/* Now emit VB and VEP state packets.
*
* This still defines a hardware VB for each input, even if they