Store clipping distance for user clip planes as part of vertex processing

Once the clipping distance is calculated and stored per vertex, the
distances can be re-used when clipping is actually performed.  This
doesn't have any immediate benefit, but it paves the way for
implementing gl_ClipDistance in vertex shaders and result.clip[] in
vertex programs.

This has not produces any oglconform regressions on my G31 system
which uses software TNL.

Signed-off-by: Ian Romanick <[email protected]>
Reviewed-by: Brian Paul <[email protected]>

1 files changed, 15 insertions, 0 deletions

diff --git a/src/mesa/tnl/t_vb_program.c b/src/mesa/tnl/t_vb_program.c
index c10a27614ff..5fb83c2b01b 100644
--- a/src/mesa/tnl/t_vb_program.c
+++ b/src/mesa/tnl/t_vb_program.c
@@ -66,6 +66,7 @@ struct vp_stage_data {
    GLvector4f results[VERT_RESULT_MAX];
 
    GLvector4f ndcCoords;              /**< normalized device coords */
+   GLfloat *clipdistance[MAX_CLIP_PLANES];
    GLubyte *clipmask;                 /**< clip flags */
    GLubyte ormask, andmask;           /**< for clipping */
 };
@@ -77,6 +78,7 @@ struct vp_stage_data {
 static void
 userclip( GLcontext *ctx,
           GLvector4f *clip,
+          GLfloat *clipdistance[MAX_CLIP_PLANES],
           GLubyte *clipmask,
           GLubyte *clipormask,
           GLubyte *clipandmask )
@@ -105,6 +107,8 @@ userclip( GLcontext *ctx,
 	       clipmask[i] |= CLIP_USER_BIT;
 	    }
 
+	    clipdistance[p][i] = dp;
+
 	    STRIDE_F(coord, stride);
 	 }
 
@@ -164,6 +168,7 @@ do_ndc_cliptest(GLcontext *ctx, struct vp_stage_data *store)
       ctx->VertexProgram.Current->IsPositionInvariant)) {
       userclip( ctx,
 		VB->ClipPtr,
+		store->clipdistance,
 		store->clipmask,
 		&store->ormask,
 		&store->andmask );
@@ -171,6 +176,9 @@ do_ndc_cliptest(GLcontext *ctx, struct vp_stage_data *store)
       if (store->andmask) {
 	 return GL_FALSE;
       }
+
+      memcpy(VB->ClipDistancePtr, store->clipdistance,
+	     sizeof(store->clipdistance));
    }
 
    VB->ClipAndMask = store->andmask;
@@ -514,6 +522,10 @@ init_vp(GLcontext *ctx, struct tnl_pipeline_stage *stage)
    _mesa_vector4f_alloc( &store->ndcCoords, 0, size, 32 );
    store->clipmask = (GLubyte *) ALIGN_MALLOC(sizeof(GLubyte)*size, 32 );
 
+   for (i = 0; i < MAX_CLIP_PLANES; i++)
+      store->clipdistance[i] =
+	 (GLfloat *) ALIGN_MALLOC(sizeof(GLfloat) * size, 32);
+
    return GL_TRUE;
 }
 
@@ -537,6 +549,9 @@ dtr(struct tnl_pipeline_stage *stage)
       _mesa_vector4f_free( &store->ndcCoords );
       ALIGN_FREE( store->clipmask );
 
+      for (i = 0; i < MAX_CLIP_PLANES; i++)
+	 ALIGN_FREE(store->clipdistance[i]);
+
       FREE( store );
       stage->privatePtr = NULL;
    }