[Mesa-dev] [PATCH 3/3] i965: Fix component mask and varying_to_slot mapping for gl_ViewportIndex

[Anuj Phogat]

gl_ViewportIndex doesn't get its own varying slot. It is stored
in VARYING_SLOT_PSIZ.z. This patch fixes the issue for both gen7
and gen8 because gen7_upload_3dstate_so_decl_list() is shared
between them.

Fixes failures in OpenGL Khronos CTS test transform_feedback_builtins.
Makes new piglit test glsl-1.50-transform-feedback-builtins pass for
'gl_ViewportIndex'.

Cc: <mesa-stable at lists.freedesktop.org>
Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
---
 src/mesa/drivers/dri/i965/gen7_sol_state.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/mesa/drivers/dri/i965/gen7_sol_state.c b/src/mesa/drivers/dri/i965/gen7_sol_state.c
index 3623238..8e554af 100644
--- a/src/mesa/drivers/dri/i965/gen7_sol_state.c
+++ b/src/mesa/drivers/dri/i965/gen7_sol_state.c
@@ -123,6 +123,7 @@ gen7_upload_3dstate_so_decl_list(struct brw_context *brw,
 
       /* gl_PointSize is stored in VARYING_SLOT_PSIZ.w
        * gl_Layer is stored in VARYING_SLOT_PSIZ.y
+       * gl_ViewportIndex is stored in VARYING_SLOT_PSIZ.z
        */
       if (varying == VARYING_SLOT_PSIZ) {
          assert(components == 1);
@@ -130,6 +131,9 @@ gen7_upload_3dstate_so_decl_list(struct brw_context *brw,
       } else if (varying == VARYING_SLOT_LAYER) {
          assert(components == 1);
          component_mask <<= 1;
+      } else if (varying == VARYING_SLOT_VIEWPORT) {
+         assert(components == 1);
+         component_mask <<= 2;
       } else {
          component_mask <<= linked_xfb_info->Outputs[i].ComponentOffset;
       }
@@ -137,7 +141,7 @@ gen7_upload_3dstate_so_decl_list(struct brw_context *brw,
       buffer_mask |= 1 << buffer;
 
       decl |= buffer << SO_DECL_OUTPUT_BUFFER_SLOT_SHIFT;
-      if (varying == VARYING_SLOT_LAYER) {
+      if (varying == VARYING_SLOT_LAYER || varying == VARYING_SLOT_VIEWPORT) {
          decl |= vue_map->varying_to_slot[VARYING_SLOT_PSIZ] <<
             SO_DECL_REGISTER_INDEX_SHIFT;
       } else {
-- 
1.8.3.1