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108 lines
3.5 KiB
C
108 lines
3.5 KiB
C
/*
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* Mesa 3-D graphics library
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* Version: 7.0
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*
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* Copyright (C) 1999-2007 Brian Paul 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 "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions 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 MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
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* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* Authors:
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* Brian Paul
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*/
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#include <precomp.h>
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struct point_stage_data {
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GLvector4f PointSize;
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};
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#define POINT_STAGE_DATA(stage) ((struct point_stage_data *)stage->privatePtr)
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/**
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* Compute point size for each vertex from the vertex eye-space Z
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* coordinate and the point size attenuation factors.
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* Only done when point size attenuation is enabled and vertex program is
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* disabled.
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*/
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static GLboolean
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run_point_stage(struct gl_context *ctx, struct tnl_pipeline_stage *stage)
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{
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if (ctx->Point._Attenuated) {
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struct point_stage_data *store = POINT_STAGE_DATA(stage);
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struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
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const GLfloat *eyeCoord = (GLfloat *) VB->EyePtr->data + 2;
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const GLint eyeCoordStride = VB->EyePtr->stride / sizeof(GLfloat);
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const GLfloat p0 = ctx->Point.Params[0];
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const GLfloat p1 = ctx->Point.Params[1];
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const GLfloat p2 = ctx->Point.Params[2];
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const GLfloat pointSize = ctx->Point.Size;
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GLfloat (*size)[4] = store->PointSize.data;
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GLuint i;
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for (i = 0; i < VB->Count; i++) {
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const GLfloat dist = FABSF(*eyeCoord);
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const GLfloat q = p0 + dist * (p1 + dist * p2);
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const GLfloat atten = (q != 0.0F) ? SQRTF(1.0F / q) : 1.0F;
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size[i][0] = pointSize * atten; /* clamping done in rasterization */
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eyeCoord += eyeCoordStride;
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}
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VB->AttribPtr[_TNL_ATTRIB_POINTSIZE] = &store->PointSize;
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}
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return GL_TRUE;
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}
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static GLboolean
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alloc_point_data(struct gl_context *ctx, struct tnl_pipeline_stage *stage)
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{
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struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
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struct point_stage_data *store;
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stage->privatePtr = malloc(sizeof(*store));
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store = POINT_STAGE_DATA(stage);
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if (!store)
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return GL_FALSE;
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_mesa_vector4f_alloc( &store->PointSize, 0, VB->Size, 32 );
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return GL_TRUE;
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}
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static void
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free_point_data(struct tnl_pipeline_stage *stage)
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{
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struct point_stage_data *store = POINT_STAGE_DATA(stage);
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if (store) {
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_mesa_vector4f_free( &store->PointSize );
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free( store );
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stage->privatePtr = NULL;
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}
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}
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const struct tnl_pipeline_stage _tnl_point_attenuation_stage =
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{
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"point size attenuation", /* name */
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NULL, /* stage private data */
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alloc_point_data, /* alloc data */
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free_point_data, /* destructor */
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NULL,
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run_point_stage /* run */
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};
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