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/*
* Mesa 3-D graphics library
* Version: 6.5
*
* Copyright (C) 1999-2006 Brian Paul All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* 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 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 NONINFRINGEMENT. IN NO EVENT SHALL
* BRIAN PAUL 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.
*
* Authors:
* Keith Whitwell <keith@tungstengraphics.com>
*/
#include "glheader.h"
#include "colormac.h"
#include "context.h"
#include "macros.h"
#include "imports.h"
#include "mtypes.h"
#include "math/m_xform.h"
#include "t_context.h"
#include "t_pipeline.h"
/* EXT_vertex_cull. Not really a big win, but probably depends on
* your application. This stage not included in the default pipeline.
*/
static GLboolean run_cull_stage( GLcontext *ctx,
struct tnl_pipeline_stage *stage )
{
TNLcontext *tnl = TNL_CONTEXT(ctx);
struct vertex_buffer *VB = &tnl->vb;
const GLfloat a = ctx->Transform.CullObjPos[0];
const GLfloat b = ctx->Transform.CullObjPos[1];
const GLfloat c = ctx->Transform.CullObjPos[2];
GLfloat *norm = (GLfloat *)VB->NormalPtr->data;
GLuint stride = VB->NormalPtr->stride;
GLuint count = VB->Count;
GLuint i;
if (ctx->ShaderObjects._VertexShaderPresent)
return GL_TRUE;
if (ctx->VertexProgram._Enabled ||
!ctx->Transform.CullVertexFlag)
return GL_TRUE;
VB->ClipOrMask &= ~CLIP_CULL_BIT;
VB->ClipAndMask |= CLIP_CULL_BIT;
for (i = 0 ; i < count ; i++) {
GLfloat dp = (norm[0] * a +
norm[1] * b +
norm[2] * c);
if (dp < 0) {
VB->ClipMask[i] |= CLIP_CULL_BIT;
VB->ClipOrMask |= CLIP_CULL_BIT;
}
else {
VB->ClipMask[i] &= ~CLIP_CULL_BIT;
VB->ClipAndMask &= ~CLIP_CULL_BIT;
}
STRIDE_F(norm, stride);
}
return !(VB->ClipAndMask & CLIP_CULL_BIT);
}
const struct tnl_pipeline_stage _tnl_vertex_cull_stage =
{
"EXT_cull_vertex",
NULL, /* private data */
NULL, /* ctr */
NULL, /* destructor */
NULL,
run_cull_stage /* run -- initially set to init */
};
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