1 | /* $Id: fog.c,v 1.3 2000-05-23 20:40:33 jeroen Exp $ */
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2 |
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3 | /*
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4 | * Mesa 3-D graphics library
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5 | * Version: 3.3
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6 | *
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7 | * Copyright (C) 1999 Brian Paul All Rights Reserved.
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8 | *
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9 | * Permission is hereby granted, free of charge, to any person obtaining a
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10 | * copy of this software and associated documentation files (the "Software"),
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11 | * to deal in the Software without restriction, including without limitation
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12 | * the rights to use, copy, modify, merge, publish, distribute, sublicense,
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13 | * and/or sell copies of the Software, and to permit persons to whom the
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14 | * Software is furnished to do so, subject to the following conditions:
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15 | *
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16 | * The above copyright notice and this permission notice shall be included
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17 | * in all copies or substantial portions of the Software.
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18 | *
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19 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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20 | * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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21 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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22 | * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
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23 | * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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24 | * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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25 | */
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26 |
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27 |
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28 | /* $XFree86: xc/lib/GL/mesa/src/fog.c,v 1.4 1999/04/04 00:20:24 dawes Exp $ */
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29 |
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30 | #ifdef PC_HEADER
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31 | #include "all.h"
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32 | #else
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33 | #include "glheader.h"
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34 | #include "types.h"
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35 | #include "context.h"
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36 | #include "fog.h"
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37 | #include "macros.h"
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38 | #include "mmath.h"
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39 | #include "xform.h"
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40 | #endif
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41 |
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42 |
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43 |
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44 | void
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45 | _mesa_Fogf(GLenum pname, GLfloat param)
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46 | {
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47 | _mesa_Fogfv(pname, ¶m);
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48 | }
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49 |
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50 |
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51 | void
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52 | _mesa_Fogi(GLenum pname, GLint param )
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53 | {
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54 | GLfloat fparam = (GLfloat) param;
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55 | _mesa_Fogfv(pname, &fparam);
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56 | }
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57 |
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58 |
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59 | void
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60 | _mesa_Fogiv(GLenum pname, const GLint *params )
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61 | {
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62 | GLfloat p[4];
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63 | switch (pname) {
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64 | case GL_FOG_MODE:
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65 | case GL_FOG_DENSITY:
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66 | case GL_FOG_START:
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67 | case GL_FOG_END:
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68 | case GL_FOG_INDEX:
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69 | p[0] = (GLfloat) *params;
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70 | break;
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71 | case GL_FOG_COLOR:
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72 | p[0] = INT_TO_FLOAT( params[0] );
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73 | p[1] = INT_TO_FLOAT( params[1] );
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74 | p[2] = INT_TO_FLOAT( params[2] );
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75 | p[3] = INT_TO_FLOAT( params[3] );
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76 | break;
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77 | default:
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78 | /* Error will be caught later in _mesa_Fogfv */
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79 | ;
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80 | }
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81 | _mesa_Fogfv(pname, p);
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82 | }
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83 |
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84 |
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85 | void
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86 | _mesa_Fogfv( GLenum pname, const GLfloat *params )
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87 | {
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88 | GET_CURRENT_CONTEXT(ctx);
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89 | GLenum m;
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90 |
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91 | switch (pname) {
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92 | case GL_FOG_MODE:
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93 | m = (GLenum) (GLint) *params;
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94 | if (m==GL_LINEAR || m==GL_EXP || m==GL_EXP2) {
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95 | ctx->Fog.Mode = m;
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96 | }
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97 | else {
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98 | gl_error( ctx, GL_INVALID_ENUM, "glFog" );
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99 | return;
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100 | }
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101 | break;
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102 | case GL_FOG_DENSITY:
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103 | if (*params<0.0) {
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104 | gl_error( ctx, GL_INVALID_VALUE, "glFog" );
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105 | return;
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106 | }
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107 | else {
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108 | ctx->Fog.Density = *params;
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109 | }
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110 | break;
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111 | case GL_FOG_START:
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112 | ctx->Fog.Start = *params;
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113 | break;
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114 | case GL_FOG_END:
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115 | ctx->Fog.End = *params;
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116 | break;
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117 | case GL_FOG_INDEX:
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118 | ctx->Fog.Index = *params;
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119 | break;
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120 | case GL_FOG_COLOR:
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121 | ctx->Fog.Color[0] = params[0];
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122 | ctx->Fog.Color[1] = params[1];
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123 | ctx->Fog.Color[2] = params[2];
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124 | ctx->Fog.Color[3] = params[3];
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125 | break;
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126 | default:
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127 | gl_error( ctx, GL_INVALID_ENUM, "glFog" );
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128 | return;
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129 | }
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130 |
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131 | if (ctx->Driver.Fogfv) {
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132 | (*ctx->Driver.Fogfv)( ctx, pname, params );
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133 | }
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134 |
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135 | ctx->NewState |= NEW_FOG;
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136 | }
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137 |
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138 |
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139 | typedef void (*fog_func)( struct vertex_buffer *VB, GLuint side,
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140 | GLubyte flag );
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141 |
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142 | typedef void (*fog_coord_func)( struct vertex_buffer *VB,
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143 | const GLvector4f *from,
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144 | GLubyte flag );
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145 |
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146 | static fog_func fog_ci_tab[2];
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147 | static fog_func fog_rgba_tab[2];
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148 | static fog_coord_func make_fog_coord_tab[2];
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149 |
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150 | /*
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151 | * Compute the fogged color for an array of vertices.
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152 | * Input: n - number of vertices
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153 | * v - array of vertices
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154 | * color - the original vertex colors
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155 | * Output: color - the fogged colors
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156 | *
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157 | */
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158 | #define TAG(x) x##_raw
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159 | #define CULLCHECK
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160 | #define IDX 0
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161 | #include "fog_tmp.h"
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162 |
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163 | #define TAG(x) x##_masked
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164 | #define CULLCHECK if (cullmask[i]&flag)
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165 | #define IDX 1
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166 | #include "fog_tmp.h"
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167 |
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168 |
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169 | void
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170 | _mesa_init_fog( void )
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171 | {
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172 | init_fog_tab_masked();
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173 | init_fog_tab_raw();
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174 | }
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175 |
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176 |
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177 | /*
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178 | * Compute fog for the vertices in the vertex buffer.
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179 | */
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180 | void
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181 | _mesa_fog_vertices( struct vertex_buffer *VB )
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182 | {
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183 | GLcontext *ctx = VB->ctx;
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184 | GLuint i = VB->CullMode & 1;
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185 |
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186 | if (ctx->Visual->RGBAflag) {
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187 | /* Fog RGB colors */
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188 | if (ctx->TriangleCaps & DD_TRI_LIGHT_TWOSIDE) {
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189 | fog_rgba_tab[i]( VB, 0, VERT_FACE_FRONT );
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190 | fog_rgba_tab[i]( VB, 1, VERT_FACE_REAR );
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191 | } else {
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192 | fog_rgba_tab[i]( VB, 0, VERT_FACE_FRONT|VERT_FACE_REAR );
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193 | }
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194 | }
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195 | else {
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196 | /* Fog color indexes */
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197 | if (ctx->TriangleCaps & DD_TRI_LIGHT_TWOSIDE) {
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198 | fog_ci_tab[i]( VB, 0, VERT_FACE_FRONT );
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199 | fog_ci_tab[i]( VB, 1, VERT_FACE_REAR );
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200 | } else {
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201 | fog_ci_tab[i]( VB, 0, VERT_FACE_FRONT|VERT_FACE_REAR );
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202 | }
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203 | }
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204 | }
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205 |
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206 |
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207 | static void check_fog_coords( GLcontext *ctx, struct gl_pipeline_stage *d )
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208 | {
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209 | d->type = 0;
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210 |
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211 | if (ctx->FogMode==FOG_FRAGMENT)
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212 | {
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213 | d->type = PIPE_IMMEDIATE|PIPE_PRECALC;
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214 | d->inputs = VERT_OBJ_ANY;
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215 | d->outputs = VERT_FOG_COORD;
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216 | }
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217 | }
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218 |
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219 |
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220 | static void gl_make_fog_coords( struct vertex_buffer *VB )
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221 | {
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222 | GLcontext *ctx = VB->ctx;
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223 |
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224 | /* If full eye coords weren't required, just calculate the eye Z
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225 | * values.
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226 | */
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227 | if (!ctx->NeedEyeCoords) {
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228 | GLfloat *m = ctx->ModelView.m;
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229 | GLfloat plane[4];
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230 |
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231 | plane[0] = m[2];
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232 | plane[1] = m[6];
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233 | plane[2] = m[10];
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234 | plane[3] = m[14];
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235 |
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236 | gl_dotprod_tab[0][VB->ObjPtr->size](&VB->Eye,
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237 | 2, /* fill z coordinates */
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238 | VB->ObjPtr,
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239 | plane,
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240 | 0 );
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241 |
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242 | make_fog_coord_tab[0]( VB, &VB->Eye, 0 );
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243 | }
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244 | else
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245 | {
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246 | make_fog_coord_tab[0]( VB, VB->EyePtr, 0 );
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247 | }
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248 | }
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249 |
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250 |
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251 | /* Drivers that want fog coordinates in VB->Spec[0] alpha, can substitute this
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252 | * stage for the default PIPE_OP_FOG pipeline stage.
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253 | */
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254 | struct gl_pipeline_stage gl_fog_coord_stage = {
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255 | "build fog coordinates",
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256 | PIPE_OP_FOG,
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257 | PIPE_PRECALC|PIPE_IMMEDIATE,
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258 | 0,
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259 | NEW_FOG,
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260 | NEW_LIGHTING|NEW_RASTER_OPS|NEW_FOG|NEW_MODELVIEW,
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261 | 0, 0,
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262 | 0, 0, 0,
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263 | check_fog_coords,
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264 | gl_make_fog_coords
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265 | };
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266 |
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267 |
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268 |
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269 |
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270 |
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271 | /*
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272 | * Apply fog to an array of RGBA pixels.
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273 | * Input: n - number of pixels
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274 | * z - array of integer depth values
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275 | * red, green, blue, alpha - pixel colors
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276 | * Output: red, green, blue, alpha - fogged pixel colors
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277 | */
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278 | void
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279 | _mesa_fog_rgba_pixels( const GLcontext *ctx,
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280 | GLuint n, const GLdepth z[], GLubyte rgba[][4] )
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281 | {
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282 | GLfloat c = ctx->ProjectionMatrix.m[10];
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283 | GLfloat d = ctx->ProjectionMatrix.m[14];
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284 | GLuint i;
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285 |
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286 | GLfloat rFog = ctx->Fog.Color[0] * 255.0F;
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287 | GLfloat gFog = ctx->Fog.Color[1] * 255.0F;
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288 | GLfloat bFog = ctx->Fog.Color[2] * 255.0F;
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289 |
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290 | GLfloat tz = ctx->Viewport.WindowMap.m[MAT_TZ];
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291 | GLfloat szInv = 1.0F / ctx->Viewport.WindowMap.m[MAT_SZ];
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292 |
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293 | switch (ctx->Fog.Mode) {
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294 | case GL_LINEAR:
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295 | {
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296 | GLfloat fogEnd = ctx->Fog.End;
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297 | GLfloat fogScale = 1.0F / (ctx->Fog.End - ctx->Fog.Start);
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298 | for (i=0;i<n;i++) {
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299 | GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
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300 | GLfloat eyez = -d / (c+ndcz);
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301 | GLfloat f, g;
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302 | if (eyez < 0.0) eyez = -eyez;
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303 | f = (fogEnd - eyez) * fogScale;
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304 | f = CLAMP( f, 0.0F, 1.0F );
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305 | g = 1.0F - f;
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306 | rgba[i][RCOMP] = (GLint) (f * rgba[i][RCOMP] + g * rFog);
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307 | rgba[i][GCOMP] = (GLint) (f * rgba[i][GCOMP] + g * gFog);
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308 | rgba[i][BCOMP] = (GLint) (f * rgba[i][BCOMP] + g * bFog);
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309 | }
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310 | }
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311 | break;
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312 | case GL_EXP:
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313 | for (i=0;i<n;i++) {
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314 | GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
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315 | GLfloat eyez = d / (c+ndcz);
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316 | GLfloat f, g;
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317 | if (eyez < 0.0)
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318 | eyez = -eyez;
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319 | f = exp( -ctx->Fog.Density * eyez );
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320 | g = 1.0F - f;
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321 | rgba[i][RCOMP] = (GLint) (f * rgba[i][RCOMP] + g * rFog);
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322 | rgba[i][GCOMP] = (GLint) (f * rgba[i][GCOMP] + g * gFog);
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323 | rgba[i][BCOMP] = (GLint) (f * rgba[i][BCOMP] + g * bFog);
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324 | }
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325 | break;
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326 | case GL_EXP2:
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327 | {
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328 | GLfloat negDensitySquared = -ctx->Fog.Density * ctx->Fog.Density;
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329 | for (i=0;i<n;i++) {
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330 | GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
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331 | GLfloat eyez = d / (c+ndcz);
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332 | GLfloat f, g;
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333 | GLfloat tmp = negDensitySquared * eyez * eyez;
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334 | #ifdef __alpha__
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335 | /* XXX this underflow check may be needed for other systems */
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336 | if (tmp < FLT_MIN_10_EXP)
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337 | f = exp( FLT_MIN_10_EXP );
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338 | else
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339 | #endif
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340 | f = exp( tmp );
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341 | g = 1.0F - f;
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342 | rgba[i][RCOMP] = (GLint) (f * rgba[i][RCOMP] + g * rFog);
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343 | rgba[i][GCOMP] = (GLint) (f * rgba[i][GCOMP] + g * gFog);
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344 | rgba[i][BCOMP] = (GLint) (f * rgba[i][BCOMP] + g * bFog);
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345 | }
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346 | }
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347 | break;
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348 | default:
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349 | gl_problem(ctx, "Bad fog mode in _mesa_fog_rgba_pixels");
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350 | return;
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351 | }
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352 | }
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353 |
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354 |
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355 |
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356 |
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357 | /*
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358 | * Apply fog to an array of color index pixels.
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359 | * Input: n - number of pixels
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360 | * z - array of integer depth values
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361 | * index - pixel color indexes
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362 | * Output: index - fogged pixel color indexes
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363 | */
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364 | void
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365 | _mesa_fog_ci_pixels( const GLcontext *ctx,
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366 | GLuint n, const GLdepth z[], GLuint index[] )
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367 | {
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368 | GLfloat c = ctx->ProjectionMatrix.m[10];
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369 | GLfloat d = ctx->ProjectionMatrix.m[14];
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370 | GLuint i;
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371 |
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372 | GLfloat tz = ctx->Viewport.WindowMap.m[MAT_TZ];
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373 | GLfloat szInv = 1.0F / ctx->Viewport.WindowMap.m[MAT_SZ];
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374 |
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375 | switch (ctx->Fog.Mode) {
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376 | case GL_LINEAR:
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377 | {
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378 | GLfloat fogEnd = ctx->Fog.End;
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379 | GLfloat fogScale = 1.0F / (ctx->Fog.End - ctx->Fog.Start);
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380 | for (i=0;i<n;i++) {
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381 | GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
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382 | GLfloat eyez = -d / (c+ndcz);
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383 | GLfloat f;
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384 | if (eyez < 0.0) eyez = -eyez;
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385 | f = (fogEnd - eyez) * fogScale;
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386 | f = CLAMP( f, 0.0F, 1.0F );
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387 | index[i] = (GLuint) ((GLfloat) index[i] + (1.0F-f) * ctx->Fog.Index);
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388 | }
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389 | }
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390 | break;
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391 | case GL_EXP:
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392 | for (i=0;i<n;i++) {
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393 | GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
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394 | GLfloat eyez = -d / (c+ndcz);
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395 | GLfloat f;
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396 | if (eyez < 0.0)
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397 | eyez = -eyez;
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398 | f = exp( -ctx->Fog.Density * eyez );
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399 | f = CLAMP( f, 0.0F, 1.0F );
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400 | index[i] = (GLuint) ((GLfloat) index[i] + (1.0F-f) * ctx->Fog.Index);
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401 | }
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402 | break;
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403 | case GL_EXP2:
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404 | {
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405 | GLfloat negDensitySquared = -ctx->Fog.Density * ctx->Fog.Density;
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406 | for (i=0;i<n;i++) {
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407 | GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
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408 | GLfloat eyez = -d / (c+ndcz);
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409 | GLfloat tmp, f;
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410 | if (eyez < 0.0)
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411 | eyez = -eyez;
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412 | tmp = negDensitySquared * eyez * eyez;
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413 | #ifdef __alpha__
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414 | /* XXX this underflow check may be needed for other systems */
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415 | if (tmp < FLT_MIN_10_EXP)
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416 | f = exp( FLT_MIN_10_EXP );
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417 | else
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418 | #endif
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419 | f = exp( tmp );
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420 | f = CLAMP( f, 0.0F, 1.0F );
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421 | index[i] = (GLuint) ((GLfloat) index[i] + (1.0F-f) * ctx->Fog.Index);
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422 | }
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423 | }
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424 | break;
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425 | default:
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426 | gl_problem(ctx, "Bad fog mode in _mesa_fog_ci_pixels");
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427 | return;
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428 | }
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429 | }
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430 |
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