draw: implement distance culling

Works similarly to clip distance. If the cull distance is negative
for all vertices against a specific plane then the primitive
is culled.

Signed-off-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/draw/draw_private.h b/src/gallium/auxiliary/draw/draw_private.h
index e081735..fd52c2d 100644
--- a/src/gallium/auxiliary/draw/draw_private.h
+++ b/src/gallium/auxiliary/draw/draw_private.h
@@ -390,6 +390,8 @@ uint draw_current_shader_viewport_index_output(const struct draw_context *draw);
 uint draw_current_shader_clipvertex_output(const struct draw_context *draw);
 uint draw_current_shader_clipdistance_output(const struct draw_context *draw, int index);
 uint draw_current_shader_num_written_clipdistances(const struct draw_context *draw);
+uint draw_current_shader_culldistance_output(const struct draw_context *draw, int index);
+uint draw_current_shader_num_written_culldistances(const struct draw_context *draw);
 int draw_alloc_extra_vertex_attrib(struct draw_context *draw,
                                    uint semantic_name, uint semantic_index);
 void draw_remove_extra_vertex_attribs(struct draw_context *draw);