src/mesa/main/fog.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  5.1
   4  *
   5  * Copyright (C) 1999-2003  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 #include "glheader.h"
  27 #include "colormac.h"
  28 #include "context.h"
  29 #include "fog.h"
  30 #include "mtypes.h"
  31
  32
  33
  34 void GLAPIENTRY
  35 _mesa_Fogf(GLenum pname, GLfloat param)
  36 {
  37    _mesa_Fogfv(pname, &param);
  38 }
  39
  40
  41 void GLAPIENTRY
  42 _mesa_Fogi(GLenum pname, GLint param )
  43 {
  44    GLfloat fparam = (GLfloat) param;
  45    _mesa_Fogfv(pname, &fparam);
  46 }
  47
  48
  49 void GLAPIENTRY
  50 _mesa_Fogiv(GLenum pname, const GLint *params )
  51 {
  52    GLfloat p[4];
  53    switch (pname) {
  54       case GL_FOG_MODE:
  55       case GL_FOG_DENSITY:
  56       case GL_FOG_START:
  57       case GL_FOG_END:
  58       case GL_FOG_INDEX:
  59       case GL_FOG_COORDINATE_SOURCE_EXT:
  60          p[0] = (GLfloat) *params;
  61          break;
  62       case GL_FOG_COLOR:
  63          p[0] = INT_TO_FLOAT( params[0] );
  64          p[1] = INT_TO_FLOAT( params[1] );
  65          p[2] = INT_TO_FLOAT( params[2] );
  66          p[3] = INT_TO_FLOAT( params[3] );
  67          break;
  68       default:
  69          /* Error will be caught later in _mesa_Fogfv */
  70          ;
  71    }
  72    _mesa_Fogfv(pname, p);
  73 }
  74
  75
  76 #define UPDATE_FOG_SCALE(ctx) do {\
  77       if (ctx->Fog.End == ctx->Fog.Start)\
  78          ctx->Fog._Scale = 1.0f;\
  79       else\
  80          ctx->Fog._Scale = 1.0f / (ctx->Fog.End - ctx->Fog.Start);\
  81    } while(0)
  82
  83
  84 void GLAPIENTRY
  85 _mesa_Fogfv( GLenum pname, const GLfloat *params )
  86 {
  87    GET_CURRENT_CONTEXT(ctx);
  88    GLenum m;
  89    ASSERT_OUTSIDE_BEGIN_END(ctx);
  90
  91    switch (pname) {
  92       case GL_FOG_MODE:
  93          m = (GLenum) (GLint) *params;
  94          switch (m) {
  95          case GL_LINEAR:
  96          case GL_EXP:
  97          case GL_EXP2:
  98             break;
  99          default:
 100             _mesa_error( ctx, GL_INVALID_ENUM, "glFog" );
 101             return;
 102          }
 103          if (ctx->Fog.Mode == m)
 104             return;
 105          FLUSH_VERTICES(ctx, _NEW_FOG);
 106          ctx->Fog.Mode = m;
 107          break;
 108       case GL_FOG_DENSITY:
 109          if (*params<0.0) {
 110             _mesa_error( ctx, GL_INVALID_VALUE, "glFog" );
 111             return;
 112          }
 113          if (ctx->Fog.Density == *params)
 114             return;
 115          FLUSH_VERTICES(ctx, _NEW_FOG);
 116          ctx->Fog.Density = *params;
 117          break;
 118       case GL_FOG_START:
 119          if (ctx->Fog.Start == *params)
 120             return;
 121          FLUSH_VERTICES(ctx, _NEW_FOG);
 122          ctx->Fog.Start = *params;
 123          UPDATE_FOG_SCALE(ctx);
 124          break;
 125       case GL_FOG_END:
 126          if (ctx->Fog.End == *params)
 127             return;
 128          FLUSH_VERTICES(ctx, _NEW_FOG);
 129          ctx->Fog.End = *params;
 130          UPDATE_FOG_SCALE(ctx);
 131          break;
 132       case GL_FOG_INDEX:
 133          if (ctx->Fog.Index == *params)
 134             return;
 135          FLUSH_VERTICES(ctx, _NEW_FOG);
 136          ctx->Fog.Index = *params;
 137          break;
 138       case GL_FOG_COLOR:
 139          if (TEST_EQ_4V(ctx->Fog.Color, params))
 140             return;
 141          FLUSH_VERTICES(ctx, _NEW_FOG);
 142          ctx->Fog.Color[0] = CLAMP(params[0], 0.0F, 1.0F);
 143          ctx->Fog.Color[1] = CLAMP(params[1], 0.0F, 1.0F);
 144          ctx->Fog.Color[2] = CLAMP(params[2], 0.0F, 1.0F);
 145          ctx->Fog.Color[3] = CLAMP(params[3], 0.0F, 1.0F);
 146          break;
 147       case GL_FOG_COORDINATE_SOURCE_EXT: {
 148          GLenum p = (GLenum) (GLint) *params;
 149          if (!ctx->Extensions.EXT_fog_coord ||
 150              (p != GL_FOG_COORDINATE_EXT && p != GL_FRAGMENT_DEPTH_EXT)) {
 151             _mesa_error(ctx, GL_INVALID_ENUM, "glFog");
 152             return;
 153          }
 154          if (ctx->Fog.FogCoordinateSource == p)
 155             return;
 156          FLUSH_VERTICES(ctx, _NEW_FOG);
 157          ctx->Fog.FogCoordinateSource = p;
 158          break;
 159       }
 160       default:
 161          _mesa_error( ctx, GL_INVALID_ENUM, "glFog" );
 162          return;
 163    }
 164
 165    if (ctx->Driver.Fogfv) {
 166       (*ctx->Driver.Fogfv)( ctx, pname, params );
 167    }
 168 }
 169
 170
 171 /**********************************************************************/
 172 /*****                      Initialization                        *****/
 173 /**********************************************************************/
 174
 175 void _mesa_init_fog( GLcontext * ctx )
 176 {
 177    /* Fog group */
 178    ctx->Fog.Enabled = GL_FALSE;
 179    ctx->Fog.Mode = GL_EXP;
 180    ASSIGN_4V( ctx->Fog.Color, 0.0, 0.0, 0.0, 0.0 );
 181    ctx->Fog.Index = 0.0;
 182    ctx->Fog.Density = 1.0;
 183    ctx->Fog.Start = 0.0;
 184    ctx->Fog.End = 1.0;
 185    ctx->Fog.ColorSumEnabled = GL_FALSE;
 186    ctx->Fog.FogCoordinateSource = GL_FRAGMENT_DEPTH_EXT;
 187    ctx->Fog._Scale = 1.0f;
 188 }