[Mesa-dev] [PATCH] i965/fs: Gen4: Zero out extra coordinates when using shadow compare

[Chris Forbes]

Fixes broken rendering if these MRFs contained anything other than zero.

NOTE: This is a candidate for stable branches.
Signed-off-by: Chris Forbes <chrisf at ijw.co.nz>
---
 src/mesa/drivers/dri/i965/brw_fs_visitor.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index 964ad40..c3eecfa 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -868,7 +868,12 @@ fs_visitor::emit_texture_gen4(ir_texture *ir, fs_reg dst, fs_reg coordinate,
 	 emit(MOV(fs_reg(MRF, base_mrf + mlen + i), coordinate));
 	 coordinate.reg_offset++;
       }
-      /* gen4's SIMD8 sampler always has the slots for u,v,r present. */
+
+      /* gen4's SIMD8 sampler always has the slots for u,v,r present.
+       * the unused slots must be zeroed.*/
+      for (int i = ir->coordinate->type->vector_elements; i<3; i++) {
+         emit(MOV(fs_reg(MRF, base_mrf + mlen + i), fs_reg(0.0f)));
+      }
       mlen += 3;
 
       if (ir->op == ir_tex) {
-- 
1.8.4