st/mesa: implement zero-stride edge flag by culling primitives

This was unimplemented.

src/mesa/state_tracker/st_atom.c

@@ -132,7 +132,7 @@ static void check_program_state( struct st_context *st )
 static void check_attrib_edgeflag(struct st_context *st)
 {
    const struct gl_client_array **arrays = st->ctx->Array._DrawArrays;
-   GLboolean vertdata_edgeflags;
+   GLboolean vertdata_edgeflags, edgeflag_culls_prims;
 
    if (!arrays)
       return;
@@ -142,6 +142,13 @@ static void check_attrib_edgeflag(struct st_context *st)
       st->vertdata_edgeflags = vertdata_edgeflags;
       st->dirty.st |= ST_NEW_EDGEFLAGS_DATA;
    }
+
+   edgeflag_culls_prims = !vertdata_edgeflags &&
+                          !st->ctx->Current.Attrib[VERT_ATTRIB_EDGEFLAG][0];
+   if (edgeflag_culls_prims != st->edgeflag_culls_prims) {
+      st->edgeflag_culls_prims = edgeflag_culls_prims;
+      st->dirty.st |= ST_NEW_RASTERIZER;
+   }
 }
 
 

src/mesa/state_tracker/st_atom_rasterizer.c

@@ -236,6 +236,14 @@ static void update_raster_state( struct st_context *st )
    /* ST_NEW_RASTERIZER */
    raster->rasterizer_discard = ctx->RasterDiscard;
 
+   if (st->edgeflag_culls_prims) {
+      /* All edge flags are FALSE. Cull the affected faces. */
+      if (raster->fill_front != PIPE_POLYGON_MODE_FILL)
+         raster->cull_face |= PIPE_FACE_FRONT;
+      if (raster->fill_back != PIPE_POLYGON_MODE_FILL)
+         raster->cull_face |= PIPE_FACE_BACK;
+   }
+
    /* _NEW_TRANSFORM */
    raster->depth_clip = ctx->Transform.DepthClamp == GL_FALSE;
    raster->clip_plane_enable = ctx->Transform.ClipPlanesEnabled;

src/mesa/state_tracker/st_context.h

@@ -131,6 +131,7 @@ struct st_context
 
    GLboolean missing_textures;
    GLboolean vertdata_edgeflags;
+   GLboolean edgeflag_culls_prims;
 
    /** Mapping from VARYING_SLOT_x to post-transformed vertex slot */
    const GLuint *vertex_result_to_slot;