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 "macros.h"
  31 #include "mtypes.h"
  32
  33
  34
  35 void GLAPIENTRY
  36 _mesa_Fogf(GLenum pname, GLfloat param)
  37 {
  38    GLfloat fparam[4];
  39    fparam[0] = param;
  40    fparam[1] = fparam[2] = fparam[3] = 0.0F;
  41    _mesa_Fogfv(pname, fparam);
  42 }
  43
  44
  45 void GLAPIENTRY
  46 _mesa_Fogi(GLenum pname, GLint param )
  47 {
  48    GLfloat fparam[4];
  49    fparam[0] = (GLfloat) param;
  50    fparam[1] = fparam[2] = fparam[3] = 0.0F;
  51    _mesa_Fogfv(pname, fparam);
  52 }
  53
  54
  55 void GLAPIENTRY
  56 _mesa_Fogiv(GLenum pname, const GLint *params )
  57 {
  58    GLfloat p[4];
  59    switch (pname) {
  60       case GL_FOG_MODE:
  61       case GL_FOG_DENSITY:
  62       case GL_FOG_START:
  63       case GL_FOG_END:
  64       case GL_FOG_INDEX:
  65       case GL_FOG_COORDINATE_SOURCE_EXT:
  66          p[0] = (GLfloat) *params;
  67          break;
  68       case GL_FOG_COLOR:
  69          p[0] = INT_TO_FLOAT( params[0] );
  70          p[1] = INT_TO_FLOAT( params[1] );
  71          p[2] = INT_TO_FLOAT( params[2] );
  72          p[3] = INT_TO_FLOAT( params[3] );
  73          break;
  74       default:
  75          /* Error will be caught later in _mesa_Fogfv */
  76          ASSIGN_4V(p, 0.0F, 0.0F, 0.0F, 0.0F);
  77    }
  78    _mesa_Fogfv(pname, p);
  79 }
  80
  81
  82 #define UPDATE_FOG_SCALE(ctx) do {\
  83       if (ctx->Fog.End == ctx->Fog.Start)\
  84          ctx->Fog._Scale = 1.0f;\
  85       else\
  86          ctx->Fog._Scale = 1.0f / (ctx->Fog.End - ctx->Fog.Start);\
  87    } while(0)
  88
  89
  90 void GLAPIENTRY
  91 _mesa_Fogfv( GLenum pname, const GLfloat *params )
  92 {
  93    GET_CURRENT_CONTEXT(ctx);
  94    GLenum m;
  95    ASSERT_OUTSIDE_BEGIN_END(ctx);
  96
  97    switch (pname) {
  98       case GL_FOG_MODE:
  99          m = (GLenum) (GLint) *params;
 100          switch (m) {
 101          case GL_LINEAR:
 102          case GL_EXP:
 103          case GL_EXP2:
 104             break;
 105          default:
 106             _mesa_error( ctx, GL_INVALID_ENUM, "glFog" );
 107             return;
 108          }
 109          if (ctx->Fog.Mode == m)
 110             return;
 111          FLUSH_VERTICES(ctx, _NEW_FOG);
 112          ctx->Fog.Mode = m;
 113          break;
 114       case GL_FOG_DENSITY:
 115          if (*params<0.0) {
 116             _mesa_error( ctx, GL_INVALID_VALUE, "glFog" );
 117             return;
 118          }
 119          if (ctx->Fog.Density == *params)
 120             return;
 121          FLUSH_VERTICES(ctx, _NEW_FOG);
 122          ctx->Fog.Density = *params;
 123          break;
 124       case GL_FOG_START:
 125          if (ctx->Fog.Start == *params)
 126             return;
 127          FLUSH_VERTICES(ctx, _NEW_FOG);
 128          ctx->Fog.Start = *params;
 129          UPDATE_FOG_SCALE(ctx);
 130          break;
 131       case GL_FOG_END:
 132          if (ctx->Fog.End == *params)
 133             return;
 134          FLUSH_VERTICES(ctx, _NEW_FOG);
 135          ctx->Fog.End = *params;
 136          UPDATE_FOG_SCALE(ctx);
 137          break;
 138       case GL_FOG_INDEX:
 139          if (ctx->Fog.Index == *params)
 140             return;
 141          FLUSH_VERTICES(ctx, _NEW_FOG);
 142          ctx->Fog.Index = *params;
 143          break;
 144       case GL_FOG_COLOR:
 145          if (TEST_EQ_4V(ctx->Fog.Color, params))
 146             return;
 147          FLUSH_VERTICES(ctx, _NEW_FOG);
 148          ctx->Fog.Color[0] = CLAMP(params[0], 0.0F, 1.0F);
 149          ctx->Fog.Color[1] = CLAMP(params[1], 0.0F, 1.0F);
 150          ctx->Fog.Color[2] = CLAMP(params[2], 0.0F, 1.0F);
 151          ctx->Fog.Color[3] = CLAMP(params[3], 0.0F, 1.0F);
 152          break;
 153       case GL_FOG_COORDINATE_SOURCE_EXT: {
 154          GLenum p = (GLenum) (GLint) *params;
 155          if (!ctx->Extensions.EXT_fog_coord ||
 156              (p != GL_FOG_COORDINATE_EXT && p != GL_FRAGMENT_DEPTH_EXT)) {
 157             _mesa_error(ctx, GL_INVALID_ENUM, "glFog");
 158             return;
 159          }
 160          if (ctx->Fog.FogCoordinateSource == p)
 161             return;
 162          FLUSH_VERTICES(ctx, _NEW_FOG);
 163          ctx->Fog.FogCoordinateSource = p;
 164          break;
 165       }
 166       default:
 167          _mesa_error( ctx, GL_INVALID_ENUM, "glFog" );
 168          return;
 169    }
 170
 171    if (ctx->Driver.Fogfv) {
 172       (*ctx->Driver.Fogfv)( ctx, pname, params );
 173    }
 174 }
 175
 176
 177 /**********************************************************************/
 178 /*****                      Initialization                        *****/
 179 /**********************************************************************/
 180
 181 void _mesa_init_fog( GLcontext * ctx )
 182 {
 183    /* Fog group */
 184    ctx->Fog.Enabled = GL_FALSE;
 185    ctx->Fog.Mode = GL_EXP;
 186    ASSIGN_4V( ctx->Fog.Color, 0.0, 0.0, 0.0, 0.0 );
 187    ctx->Fog.Index = 0.0;
 188    ctx->Fog.Density = 1.0;
 189    ctx->Fog.Start = 0.0;
 190    ctx->Fog.End = 1.0;
 191    ctx->Fog.ColorSumEnabled = GL_FALSE;
 192    ctx->Fog.FogCoordinateSource = GL_FRAGMENT_DEPTH_EXT;
 193    ctx->Fog._Scale = 1.0f;
 194 }