+++ /dev/null
-/*
- * 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 <precomp.h>
-
-struct fog_stage_data {
- GLvector4f fogcoord; /* has actual storage allocated */
-};
-
-#define FOG_STAGE_DATA(stage) ((struct fog_stage_data *)stage->privatePtr)
-
-#define FOG_EXP_TABLE_SIZE 256
-#define FOG_MAX (10.0)
-#define EXP_FOG_MAX .0006595
-#define FOG_INCR (FOG_MAX/FOG_EXP_TABLE_SIZE)
-static GLfloat exp_table[FOG_EXP_TABLE_SIZE];
-static GLfloat inited = 0;
-
-#if 1
-#define NEG_EXP( result, narg ) \
-do { \
- GLfloat f = (GLfloat) (narg * (1.0/FOG_INCR)); \
- GLint k = (GLint) f; \
- if (k > FOG_EXP_TABLE_SIZE-2) \
- result = (GLfloat) EXP_FOG_MAX; \
- else \
- result = exp_table[k] + (f-k)*(exp_table[k+1]-exp_table[k]); \
-} while (0)
-#else
-#define NEG_EXP( result, narg ) \
-do { \
- result = exp(-narg); \
-} while (0)
-#endif
-
-
-/**
- * Initialize the exp_table[] lookup table for approximating exp().
- */
-static void
-init_static_data( void )
-{
- GLfloat f = 0.0F;
- GLint i = 0;
- for ( ; i < FOG_EXP_TABLE_SIZE ; i++, f += FOG_INCR) {
- exp_table[i] = EXPF(-f);
- }
- inited = 1;
-}
-
-
-/**
- * Compute per-vertex fog blend factors from fog coordinates by
- * evaluating the GL_LINEAR, GL_EXP or GL_EXP2 fog function.
- * Fog coordinates are distances from the eye (typically between the
- * near and far clip plane distances).
- * Note that fogcoords may be negative, if eye z is source absolute
- * value must be taken earlier.
- * Fog blend factors are in the range [0,1].
- */
-static void
-compute_fog_blend_factors(struct gl_context *ctx, GLvector4f *out, const GLvector4f *in)
-{
- GLfloat end = ctx->Fog.End;
- GLfloat *v = in->start;
- GLuint stride = in->stride;
- GLuint n = in->count;
- GLfloat (*data)[4] = out->data;
- GLfloat d;
- GLuint i;
-
- out->count = in->count;
-
- switch (ctx->Fog.Mode) {
- case GL_LINEAR:
- if (ctx->Fog.Start == ctx->Fog.End)
- d = 1.0F;
- else
- d = 1.0F / (ctx->Fog.End - ctx->Fog.Start);
- for ( i = 0 ; i < n ; i++, STRIDE_F(v, stride)) {
- const GLfloat z = *v;
- GLfloat f = (end - z) * d;
- data[i][0] = CLAMP(f, 0.0F, 1.0F);
- }
- break;
- case GL_EXP:
- d = ctx->Fog.Density;
- for ( i = 0 ; i < n ; i++, STRIDE_F(v,stride)) {
- const GLfloat z = *v;
- NEG_EXP( data[i][0], d * z );
- }
- break;
- case GL_EXP2:
- d = ctx->Fog.Density*ctx->Fog.Density;
- for ( i = 0 ; i < n ; i++, STRIDE_F(v, stride)) {
- const GLfloat z = *v;
- NEG_EXP( data[i][0], d * z * z );
- }
- break;
- default:
- _mesa_problem(ctx, "Bad fog mode in make_fog_coord");
- return;
- }
-}
-
-
-static GLboolean
-run_fog_stage(struct gl_context *ctx, struct tnl_pipeline_stage *stage)
-{
- TNLcontext *tnl = TNL_CONTEXT(ctx);
- struct vertex_buffer *VB = &tnl->vb;
- struct fog_stage_data *store = FOG_STAGE_DATA(stage);
- GLvector4f *input;
-
-
- if (!ctx->Fog.Enabled)
- return GL_TRUE;
-
- if (ctx->Fog.FogCoordinateSource == GL_FRAGMENT_DEPTH_EXT) {
- GLuint i;
- GLfloat *coord;
- /* Fog is computed from vertex or fragment Z values */
- /* source = VB->AttribPtr[_TNL_ATTRIB_POS] or VB->EyePtr coords */
- /* dest = VB->AttribPtr[_TNL_ATTRIB_FOG] = fog stage private storage */
- VB->AttribPtr[_TNL_ATTRIB_FOG] = &store->fogcoord;
-
- if (!ctx->_NeedEyeCoords) {
- /* compute fog coords from object coords */
- const GLfloat *m = ctx->ModelviewMatrixStack.Top->m;
- GLfloat plane[4];
-
- /* Use this to store calculated eye z values:
- */
- input = &store->fogcoord;
-
- plane[0] = m[2];
- plane[1] = m[6];
- plane[2] = m[10];
- plane[3] = m[14];
- /* Full eye coords weren't required, just calculate the
- * eye Z values.
- */
- _mesa_dotprod_tab[VB->AttribPtr[_TNL_ATTRIB_POS]->size]
- ( (GLfloat *) input->data,
- 4 * sizeof(GLfloat),
- VB->AttribPtr[_TNL_ATTRIB_POS], plane );
-
- input->count = VB->AttribPtr[_TNL_ATTRIB_POS]->count;
-
- /* make sure coords are really positive
- NOTE should avoid going through array twice */
- coord = input->start;
- for (i = 0; i < input->count; i++) {
- *coord = FABSF(*coord);
- STRIDE_F(coord, input->stride);
- }
- }
- else {
- /* fog coordinates = eye Z coordinates - need to copy for ABS */
- input = &store->fogcoord;
-
- if (VB->EyePtr->size < 2)
- _mesa_vector4f_clean_elem( VB->EyePtr, VB->Count, 2 );
-
- input->stride = 4 * sizeof(GLfloat);
- input->count = VB->EyePtr->count;
- coord = VB->EyePtr->start;
- for (i = 0 ; i < VB->EyePtr->count; i++) {
- input->data[i][0] = FABSF(coord[2]);
- STRIDE_F(coord, VB->EyePtr->stride);
- }
- }
- }
- else {
- /* use glFogCoord() coordinates */
- input = VB->AttribPtr[_TNL_ATTRIB_FOG]; /* source data */
-
- /* input->count may be one if glFogCoord was only called once
- * before glBegin. But we need to compute fog for all vertices.
- */
- input->count = VB->AttribPtr[_TNL_ATTRIB_POS]->count;
-
- VB->AttribPtr[_TNL_ATTRIB_FOG] = &store->fogcoord; /* dest data */
- }
-
- if (tnl->_DoVertexFog) {
- /* compute blend factors from fog coordinates */
- compute_fog_blend_factors( ctx, VB->AttribPtr[_TNL_ATTRIB_FOG], input );
- }
- else {
- /* results = incoming fog coords (compute fog per-fragment later) */
- VB->AttribPtr[_TNL_ATTRIB_FOG] = input;
- }
-
- return GL_TRUE;
-}
-
-
-
-/* Called the first time stage->run() is invoked.
- */
-static GLboolean
-alloc_fog_data(struct gl_context *ctx, struct tnl_pipeline_stage *stage)
-{
- TNLcontext *tnl = TNL_CONTEXT(ctx);
- struct fog_stage_data *store;
- stage->privatePtr = MALLOC(sizeof(*store));
- store = FOG_STAGE_DATA(stage);
- if (!store)
- return GL_FALSE;
-
- _mesa_vector4f_alloc( &store->fogcoord, 0, tnl->vb.Size, 32 );
-
- if (!inited)
- init_static_data();
-
- return GL_TRUE;
-}
-
-
-static void
-free_fog_data(struct tnl_pipeline_stage *stage)
-{
- struct fog_stage_data *store = FOG_STAGE_DATA(stage);
- if (store) {
- _mesa_vector4f_free( &store->fogcoord );
- FREE( store );
- stage->privatePtr = NULL;
- }
-}
-
-
-const struct tnl_pipeline_stage _tnl_fog_coordinate_stage =
-{
- "build fog coordinates", /* name */
- NULL, /* private_data */
- alloc_fog_data, /* dtr */
- free_fog_data, /* dtr */
- NULL, /* check */
- run_fog_stage /* run -- initially set to init. */
-};
projects / reactos.git / blobdiff