128 lines
3.4 KiB
C
128 lines
3.4 KiB
C
/**************************************************************************
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*
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* Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
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* All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sub license, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice (including the
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* next paragraph) shall be included in all copies or substantial portions
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* of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
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* IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
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* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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**************************************************************************/
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/* Authors: Keith Whitwell <keith@tungstengraphics.com>
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*/
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#include "main/imports.h"
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#include "pipe/p_defines.h"
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#include "draw_private.h"
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struct cull_stage {
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struct prim_stage stage;
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GLuint mode;
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};
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static INLINE struct cull_stage *cull_stage( struct prim_stage *stage )
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{
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return (struct cull_stage *)stage;
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}
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static void cull_begin( struct prim_stage *stage )
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{
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struct cull_stage *cull = cull_stage(stage);
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cull->mode = stage->draw->setup.cull_mode;
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stage->next->begin( stage->next );
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}
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static void cull_tri( struct prim_stage *stage,
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struct prim_header *header )
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{
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/* Window coords: */
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GLfloat *v0 = (GLfloat *)&(header->v[0]->data[0]);
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GLfloat *v1 = (GLfloat *)&(header->v[1]->data[0]);
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GLfloat *v2 = (GLfloat *)&(header->v[2]->data[0]);
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GLfloat ex = v0[0] - v2[0];
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GLfloat ey = v0[1] - v2[1];
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GLfloat fx = v1[0] - v2[0];
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GLfloat fy = v1[1] - v2[1];
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header->det = ex * fy - ey * fx;
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_mesa_printf("%s %f\n", __FUNCTION__, header->det );
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if (header->det != 0) {
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/* non-zero area */
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GLuint mode = (header->det < 0) ? PIPE_WINDING_CW : PIPE_WINDING_CCW;
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if ((mode & cull_stage(stage)->mode) == 0) {
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/* triangle is not culled, pass to next stage */
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stage->next->tri( stage->next, header );
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}
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}
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}
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static void cull_line( struct prim_stage *stage,
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struct prim_header *header )
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{
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stage->next->line( stage->next, header );
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}
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static void cull_point( struct prim_stage *stage,
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struct prim_header *header )
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{
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stage->next->point( stage->next, header );
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}
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static void cull_end( struct prim_stage *stage )
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{
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stage->next->end( stage->next );
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}
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/**
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* Create a new polygon culling stage.
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*/
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struct prim_stage *prim_cull( struct draw_context *draw )
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{
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struct cull_stage *cull = CALLOC_STRUCT(cull_stage);
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prim_alloc_tmps( &cull->stage, 0 );
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cull->stage.draw = draw;
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cull->stage.next = NULL;
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cull->stage.begin = cull_begin;
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cull->stage.point = cull_point;
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cull->stage.line = cull_line;
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cull->stage.tri = cull_tri;
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cull->stage.end = cull_end;
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return &cull->stage;
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}
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