i965: Emit writes to viewport index

This variable is handled in a fashion identical to gl_Layer.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
index 3b8cef6..f6dc3a8 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
@@ -2772,6 +2772,10 @@ vec4_visitor::emit_psiz_and_flags(struct brw_reg reg)
          emit(MOV(retype(brw_writemask(reg, WRITEMASK_Y), BRW_REGISTER_TYPE_D),
                   src_reg(output_reg[VARYING_SLOT_LAYER])));
       }
+      if (prog_data->vue_map.slots_valid & VARYING_BIT_VIEWPORT) {
+         emit(MOV(retype(brw_writemask(reg, WRITEMASK_Z), BRW_REGISTER_TYPE_D),
+                  src_reg(output_reg[VARYING_SLOT_VIEWPORT])));
+      }
    }
 }
 

diff --git a/src/mesa/drivers/dri/i965/brw_vs.c b/src/mesa/drivers/dri/i965/brw_vs.c
index 3c1cfa4..0e9470f 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_vs.c
+++ b/src/mesa/drivers/dri/i965/brw_vs.c
@@ -60,10 +60,10 @@ brw_compute_vue_map(struct brw_context *brw, struct brw_vue_map *vue_map,
    vue_map->slots_valid = slots_valid;
    int i;
 
-   /* gl_Layer doesn't get its own varying slot--it's stored in the virst VUE
-    * slot (VARYING_SLOT_PSIZ).
+   /* gl_Layer and gl_ViewportIndex don't get their own varying slots -- they
+    * are stored in the virst VUE slot (VARYING_SLOT_PSIZ).
     */
-   slots_valid &= ~VARYING_BIT_LAYER;
+   slots_valid &= ~(VARYING_BIT_LAYER | VARYING_BIT_VIEWPORT);
 
    /* Make sure that the values we store in vue_map->varying_to_slot and
     * vue_map->slot_to_varying won't overflow the signed chars that are used