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/*
* Mesa 3-D graphics library
* Version: 7.0
*
* Copyright (C) 1999-2007 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:
* Brian Paul
*/
#include "mtypes.h"
#include "imports.h"
#include "t_context.h"
#include "t_pipeline.h"
struct point_stage_data {
GLvector4f PointSize;
};
#define POINT_STAGE_DATA(stage) ((struct point_stage_data *)stage->privatePtr)
/**
* Compute point size for each vertex from the vertex eye-space Z
* coordinate and the point size attenuation factors.
* Only done when point size attenuation is enabled and vertex program is
* disabled.
*/
static GLboolean
run_point_stage(GLcontext *ctx, struct tnl_pipeline_stage *stage)
{
if (ctx->Point._Attenuated && !ctx->VertexProgram._Current) {
struct point_stage_data *store = POINT_STAGE_DATA(stage);
struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
const GLfloat *eyeCoord = (GLfloat *) VB->EyePtr->data + 2;
const GLint eyeCoordStride = VB->EyePtr->stride / sizeof(GLfloat);
const GLfloat p0 = ctx->Point.Params[0];
const GLfloat p1 = ctx->Point.Params[1];
const GLfloat p2 = ctx->Point.Params[2];
const GLfloat pointSize = ctx->Point.Size;
GLfloat (*size)[4] = store->PointSize.data;
GLuint i;
for (i = 0; i < VB->Count; i++) {
const GLfloat dist = FABSF(*eyeCoord);
const GLfloat q = p0 + dist * (p1 + dist * p2);
const GLfloat atten = (q != 0.0) ? SQRTF(1.0 / q) : 1.0;
size[i][0] = pointSize * atten; /* clamping done in rasterization */
eyeCoord += eyeCoordStride;
}
VB->AttribPtr[_TNL_ATTRIB_POINTSIZE] = &store->PointSize;
}
return GL_TRUE;
}
static GLboolean
alloc_point_data(GLcontext *ctx, struct tnl_pipeline_stage *stage)
{
struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
struct point_stage_data *store;
stage->privatePtr = _mesa_malloc(sizeof(*store));
store = POINT_STAGE_DATA(stage);
if (!store)
return GL_FALSE;
_mesa_vector4f_alloc( &store->PointSize, 0, VB->Size, 32 );
return GL_TRUE;
}
static void
free_point_data(struct tnl_pipeline_stage *stage)
{
struct point_stage_data *store = POINT_STAGE_DATA(stage);
if (store) {
_mesa_vector4f_free( &store->PointSize );
_mesa_free( store );
stage->privatePtr = NULL;
}
}
const struct tnl_pipeline_stage _tnl_point_attenuation_stage =
{
"point size attenuation", /* name */
NULL, /* stage private data */
alloc_point_data, /* alloc data */
free_point_data, /* destructor */
NULL,
run_point_stage /* run */
};
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