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 <[email protected]>
Reviewed-by: Jose Fonseca <[email protected]>
Reviewed-by: Brian Paul <[email protected]>
Reviewed-by: Roland Scheidegger <[email protected]>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/draw/draw_vs.h b/src/gallium/auxiliary/draw/draw_vs.h
index 798b004ebd4..7635abaade5 100644
--- a/src/gallium/auxiliary/draw/draw_vs.h
+++ b/src/gallium/auxiliary/draw/draw_vs.h
@@ -113,6 +113,7 @@ struct draw_vertex_shader {
    unsigned edgeflag_output;
    unsigned clipvertex_output;
    unsigned clipdistance_output[2];
+   unsigned culldistance_output[2];
    /* Extracted from shader:
     */
    const float (*immediates)[4];