[Mesa-dev] [PATCH 6/8] draw: fix front face injection

[Zack Rusin]

Inject front face only if the fragment shader uses it and
propagate through all channels because otherwise we'll
need to figure out the exact swizzle that the fs expects and
it's just simpler to make sure all the components within
the front face register are correctly set.

Signed-off-by: Zack Rusin <zackr at vmware.com>
---
 src/gallium/auxiliary/draw/draw_pipe_unfilled.c |   24 ++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/src/gallium/auxiliary/draw/draw_pipe_unfilled.c b/src/gallium/auxiliary/draw/draw_pipe_unfilled.c
index d8a603f..f9a31b0 100644
--- a/src/gallium/auxiliary/draw/draw_pipe_unfilled.c
+++ b/src/gallium/auxiliary/draw/draw_pipe_unfilled.c
@@ -37,6 +37,7 @@
 #include "pipe/p_defines.h"
 #include "draw_private.h"
 #include "draw_pipe.h"
+#include "draw_fs.h"
 
 
 struct unfilled_stage {
@@ -67,18 +68,20 @@ inject_front_face_info(struct draw_stage *stage,
       (stage->draw->rasterizer->front_ccw && ccw) ||
       (!stage->draw->rasterizer->front_ccw && !ccw));
    unsigned slot = unfilled->face_slot;
-   struct vertex_header *v0 = header->v[0];
-   struct vertex_header *v1 = header->v[1];
-   struct vertex_header *v2 = header->v[2];
+   unsigned i;
 
    /* In case the backend doesn't care about it */
    if (slot < 0) {
       return;
    }
 
-   v0->data[slot][0] = is_front_face;
-   v1->data[slot][0] = is_front_face;
-   v2->data[slot][0] = is_front_face;
+   for (i = 0; i < 3; ++i) {
+      struct vertex_header *v = header->v[i];
+      v->data[slot][0] = is_front_face;
+      v->data[slot][1] = is_front_face;
+      v->data[slot][2] = is_front_face;
+      v->data[slot][3] = is_front_face;
+   }
 }
 
    
@@ -231,9 +234,12 @@ draw_unfilled_prepare_outputs( struct draw_context *draw,
 {
    struct unfilled_stage *unfilled = unfilled_stage(stage);
    const struct pipe_rasterizer_state *rast = draw ? draw->rasterizer : 0;
-   if (rast &&
-       (rast->fill_front != PIPE_POLYGON_MODE_FILL ||
-        rast->fill_back != PIPE_POLYGON_MODE_FILL)) {
+   boolean is_unfilled = (rast &&
+                          (rast->fill_front != PIPE_POLYGON_MODE_FILL ||
+                           rast->fill_back != PIPE_POLYGON_MODE_FILL));
+   const struct draw_fragment_shader *fs = draw->fs.fragment_shader;
+   
+   if (is_unfilled && fs && fs->info.uses_frontface)  {
       unfilled->face_slot = draw_alloc_extra_vertex_attrib(
          stage->draw, TGSI_SEMANTIC_FACE, 0);
    } else {
-- 
1.7.10.4