draw: some changes to allow for runtime changes to userclip planes

[mesa.git] / src / gallium / auxiliary / draw / draw_pipe_cull.c

diff --git a/src/gallium/auxiliary/draw/draw_pipe_cull.c b/src/gallium/auxiliary/draw/draw_pipe_cull.c
index 11b39db5990b2541ca71fe0b7e41450322cb2127..2f4d01d23ab0ad4aaf078135db0f7195a30f20dd 100644 (file)
--- a/src/gallium/auxiliary/draw/draw_pipe_cull.c
+++ b/src/gallium/auxiliary/draw/draw_pipe_cull.c
@@ -40,7 +40,8 @@
 
 struct cull_stage {
    struct draw_stage stage;
-   unsigned winding;  /**< which winding(s) to cull (one of PIPE_WINDING_x) */
+   unsigned cull_face;  /**< which face(s) to cull (one of PIPE_FACE_x) */
+   unsigned front_ccw;
 };
 
 
@@ -50,8 +51,6 @@ static INLINE struct cull_stage *cull_stage( struct draw_stage *stage )
 }
 
 
-
-
 static void cull_tri( struct draw_stage *stage,
                      struct prim_header *header )
 {
@@ -62,7 +61,7 @@ static void cull_tri( struct draw_stage *stage,
    const float *v1 = header->v[1]->data[pos];
    const float *v2 = header->v[2]->data[pos];
 
-   /* edge vectors e = v0 - v2, f = v1 - v2 */
+   /* edge vectors: e = v0 - v2, f = v1 - v2 */
    const float ex = v0[0] - v2[0];
    const float ey = v0[1] - v2[1];
    const float fx = v1[0] - v2[0];
@@ -72,37 +71,42 @@ static void cull_tri( struct draw_stage *stage,
    header->det = ex * fy - ey * fx;
 
    if (header->det != 0) {
-      /* if (det < 0 then Z points toward camera and triangle is 
+      /* if det < 0 then Z points toward the camera and the triangle is 
        * counter-clockwise winding.
        */
-      unsigned winding = (header->det < 0) ? PIPE_WINDING_CCW : PIPE_WINDING_CW;
+      unsigned ccw = (header->det < 0);
+      unsigned face = ((ccw == cull_stage(stage)->front_ccw) ?
+                       PIPE_FACE_FRONT :
+                       PIPE_FACE_BACK);
 
-      if ((winding & cull_stage(stage)->winding) == 0) {
+      if ((face & cull_stage(stage)->cull_face) == 0) {
          /* triangle is not culled, pass to next stage */
         stage->next->tri( stage->next, header );
       }
    }
 }
 
+
 static void cull_first_tri( struct draw_stage *stage, 
                            struct prim_header *header )
 {
    struct cull_stage *cull = cull_stage(stage);
 
-   cull->winding = stage->draw->rasterizer->cull_mode;
+   cull->cull_face = stage->draw->rasterizer->cull_face;
+   cull->front_ccw = stage->draw->rasterizer->front_ccw;
 
    stage->tri = cull_tri;
    stage->tri( stage, header );
 }
 
 
-
 static void cull_flush( struct draw_stage *stage, unsigned flags )
 {
    stage->tri = cull_first_tri;
    stage->next->flush( stage->next, flags );
 }
 
+
 static void cull_reset_stipple_counter( struct draw_stage *stage )
 {
    stage->next->reset_stipple_counter( stage->next );
@@ -125,9 +129,6 @@ struct draw_stage *draw_cull_stage( struct draw_context *draw )
    if (cull == NULL)
       goto fail;
 
-   if (!draw_alloc_temp_verts( &cull->stage, 0 ))
-      goto fail;
-
    cull->stage.draw = draw;
    cull->stage.name = "cull";
    cull->stage.next = NULL;
@@ -138,9 +139,12 @@ struct draw_stage *draw_cull_stage( struct draw_context *draw )
    cull->stage.reset_stipple_counter = cull_reset_stipple_counter;
    cull->stage.destroy = cull_destroy;
 
+   if (!draw_alloc_temp_verts( &cull->stage, 0 ))
+      goto fail;
+
    return &cull->stage;
 
- fail:
+fail:
    if (cull)
       cull->stage.destroy( &cull->stage );