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/* $Id: t_vb_points.c,v 1.2 2001/03/03 20:33:31 brianp Exp $ */
/*
* Mesa 3-D graphics library
* Version: 3.5
*
* Copyright (C) 1999-2000 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.
*
* Author:
* Brian Paul <brian@valinux.com>
*/
#include "mtypes.h"
#include "mem.h"
#include "t_context.h"
#include "t_pipeline.h"
struct point_stage_data {
GLvector1f PointSize;
};
#define POINT_STAGE_DATA(stage) ((struct point_stage_data *)stage->private)
/*
* Compute attenuated point sizes
*/
static GLboolean run_point_stage( GLcontext *ctx,
struct gl_pipeline_stage *stage )
{
struct point_stage_data *store = POINT_STAGE_DATA(stage);
struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
const GLfloat (*eye)[4] = (const GLfloat (*)[4]) VB->EyePtr->data;
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 = store->PointSize.data;
GLuint i;
if (stage->changed_inputs) {
/* XXX do threshold and min/max clamping here? */
for (i = 0; i < VB->Count; i++) {
const GLfloat dist = -eye[i][2];
/* GLfloat dist = GL_SQRT(pos[0]*pos[0]+pos[1]*pos[1]+pos[2]*pos[2]);*/
size[i] = pointSize / (p0 + dist * (p1 + dist * p2));
}
}
VB->PointSizePtr = &store->PointSize;
return GL_TRUE;
}
/* If point size attenuation is on we'll compute the point size for
* each vertex in a special pipeline stage.
*/
static void check_point_size( GLcontext *ctx, struct gl_pipeline_stage *d )
{
d->active = ctx->Point._Attenuated;
}
static GLboolean alloc_point_data( GLcontext *ctx,
struct gl_pipeline_stage *stage )
{
struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
struct point_stage_data *store;
stage->private = MALLOC(sizeof(*store));
store = POINT_STAGE_DATA(stage);
if (!store)
return GL_FALSE;
_mesa_vector1f_alloc( &store->PointSize, 0, VB->Size, 32 );
/* Now run the stage.
*/
stage->run = run_point_stage;
return stage->run( ctx, stage );
}
static void free_point_data( struct gl_pipeline_stage *stage )
{
struct point_stage_data *store = POINT_STAGE_DATA(stage);
if (store) {
_mesa_vector1f_free( &store->PointSize );
FREE( store );
stage->private = 0;
}
}
const struct gl_pipeline_stage _tnl_point_attenuation_stage =
{
"point size attenuation", /* name */
_NEW_POINT, /* build_state_change */
_NEW_POINT, /* run_state_change */
0, /* active */
VERT_EYE, /* inputs */
VERT_POINT_SIZE, /* outputs */
0, /* changed_inputs (temporary value) */
0, /* stage private data */
free_point_data, /* destructor */
check_point_size, /* check */
alloc_point_data /* run -- initially set to alloc data */
};
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