/**************************************************************************
- *
- * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
+ *
+ * Copyright 2007 VMware, Inc.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
- *
+ *
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
- *
+ *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
- * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
- *
+ *
**************************************************************************/
/**
* \brief Drawing stage for polygon culling
*/
-/* Authors: Keith Whitwell <keith@tungstengraphics.com>
+/* Authors: Keith Whitwell <keithw@vmware.com>
*/
+#include "util/u_math.h"
#include "util/u_memory.h"
#include "pipe/p_defines.h"
#include "draw_pipe.h"
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;
};
-static INLINE struct cull_stage *cull_stage( struct draw_stage *stage )
+static inline struct cull_stage *cull_stage( struct draw_stage *stage )
{
return (struct cull_stage *)stage;
}
-
-
-
+/*
+ * Triangles can be culled using regular face cull.
+ */
static void cull_tri( struct draw_stage *stage,
struct prim_header *header )
{
- const unsigned pos = stage->draw->vs.position_output;
-
- /* Window coords: */
- const float *v0 = header->v[0]->data[pos];
- const float *v1 = header->v[1]->data[pos];
- const float *v2 = header->v[2]->data[pos];
-
- /* 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];
- const float fy = v1[1] - v2[1];
-
- /* det = cross(e,f).z */
- header->det = ex * fy - ey * fx;
-
- if (header->det != 0) {
- /* if (det < 0 then Z points toward camera and triangle is
- * counter-clockwise winding.
- */
- unsigned winding = (header->det < 0) ? PIPE_WINDING_CCW : PIPE_WINDING_CW;
-
- if ((winding & cull_stage(stage)->winding) == 0) {
- /* triangle is not culled, pass to next stage */
- stage->next->tri( stage->next, header );
+ /* Do the regular face culling */
+ {
+ const unsigned pos = draw_current_shader_position_output(stage->draw);
+ /* Window coords: */
+ const float *v0 = header->v[0]->data[pos];
+ const float *v1 = header->v[1]->data[pos];
+ const float *v2 = header->v[2]->data[pos];
+
+ /* 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];
+ const float fy = v1[1] - v2[1];
+
+
+ /* det = cross(e,f).z */
+ header->det = ex * fy - ey * fx;
+
+ if (header->det != 0) {
+ /* if det < 0 then Z points toward the camera and the triangle is
+ * counter-clockwise winding.
+ */
+ unsigned ccw = (header->det < 0);
+ unsigned face = ((ccw == cull_stage(stage)->front_ccw) ?
+ PIPE_FACE_FRONT :
+ PIPE_FACE_BACK);
+
+ if ((face & cull_stage(stage)->cull_face) == 0) {
+ /* triangle is not culled, pass to next stage */
+ stage->next->tri( stage->next, header );
+ }
+ } else {
+ /*
+ * With zero area, this is back facing (because the spec says
+ * it's front facing if sign is positive?).
+ * Some apis apparently do not allow us to cull zero area tris
+ * here, in case of fill mode line (which is rather lame).
+ */
+ if ((PIPE_FACE_BACK & cull_stage(stage)->cull_face) == 0) {
+ stage->next->tri( stage->next, header );
+ }
}
}
}
-static void cull_first_tri( struct draw_stage *stage,
+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 );
struct draw_stage *draw_cull_stage( struct draw_context *draw )
{
struct cull_stage *cull = CALLOC_STRUCT(cull_stage);
- if (cull == NULL)
- goto fail;
-
- if (!draw_alloc_temp_verts( &cull->stage, 0 ))
+ if (!cull)
goto fail;
cull->stage.draw = draw;
+ cull->stage.name = "cull";
cull->stage.next = NULL;
cull->stage.point = draw_pipe_passthrough_point;
cull->stage.line = draw_pipe_passthrough_line;
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 );
projects / mesa.git / blobdiff