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