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  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  23  * OTHER DEALINGS IN THE SOFTWARE.
  24  */
  25
  26
  27 #include "glheader.h"
  28 #include "colormac.h"
  29 #include "context.h"
  30 #include "fog.h"
  31 #include "macros.h"
  32 #include "mtypes.h"
  33
  34
  35
  36 void GLAPIENTRY
  37 _mesa_Fogf(GLenum pname, GLfloat param)
  38 {
  39    GLfloat fparam[4];
  40    fparam[0] = param;
  41    fparam[1] = fparam[2] = fparam[3] = 0.0F;
  42    _mesa_Fogfv(pname, fparam);
  43 }
  44
  45
  46 void GLAPIENTRY
  47 _mesa_Fogi(GLenum pname, GLint param )
  48 {
  49    GLfloat fparam[4];
  50    fparam[0] = (GLfloat) param;
  51    fparam[1] = fparam[2] = fparam[3] = 0.0F;
  52    _mesa_Fogfv(pname, fparam);
  53 }
  54
  55
  56 void GLAPIENTRY
  57 _mesa_Fogiv(GLenum pname, const GLint *params )
  58 {
  59    GLfloat p[4];
  60    switch (pname) {
  61       case GL_FOG_MODE:
  62       case GL_FOG_DENSITY:
  63       case GL_FOG_START:
  64       case GL_FOG_END:
  65       case GL_FOG_INDEX:
  66       case GL_FOG_COORDINATE_SOURCE_EXT:
  67          p[0] = (GLfloat) *params;
  68          break;
  69       case GL_FOG_COLOR:
  70          p[0] = INT_TO_FLOAT( params[0] );
  71          p[1] = INT_TO_FLOAT( params[1] );
  72          p[2] = INT_TO_FLOAT( params[2] );
  73          p[3] = INT_TO_FLOAT( params[3] );
  74          break;
  75       default:
  76          /* Error will be caught later in _mesa_Fogfv */
  77          ASSIGN_4V(p, 0.0F, 0.0F, 0.0F, 0.0F);
  78    }
  79    _mesa_Fogfv(pname, p);
  80 }
  81
  82
  83 /**
  84  * Update the gl_fog_attrib::_Scale field.
  85  */
  86 static void
  87 update_fog_scale(struct gl_context *ctx)
  88 {
  89    if (ctx->Fog.End == ctx->Fog.Start)
  90       ctx->Fog._Scale = 1.0f;
  91    else
  92       ctx->Fog._Scale = 1.0f / (ctx->Fog.End - ctx->Fog.Start);
  93 }
  94
  95
  96 void GLAPIENTRY
  97 _mesa_Fogfv( GLenum pname, const GLfloat *params )
  98 {
  99    GET_CURRENT_CONTEXT(ctx);
 100    GLenum m;
 101
 102    switch (pname) {
 103       case GL_FOG_MODE:
 104          m = (GLenum) (GLint) *params;
 105          switch (m) {
 106          case GL_LINEAR:
 107          case GL_EXP:
 108          case GL_EXP2:
 109             break;
 110          default:
 111             _mesa_error( ctx, GL_INVALID_ENUM, "glFog" );
 112             return;
 113          }
 114          if (ctx->Fog.Mode == m)
 115             return;
 116          FLUSH_VERTICES(ctx, _NEW_FOG);
 117          ctx->Fog.Mode = m;
 118          break;
 119       case GL_FOG_DENSITY:
 120          if (*params<0.0) {
 121             _mesa_error( ctx, GL_INVALID_VALUE, "glFog" );
 122             return;
 123          }
 124          if (ctx->Fog.Density == *params)
 125             return;
 126          FLUSH_VERTICES(ctx, _NEW_FOG);
 127          ctx->Fog.Density = *params;
 128          break;
 129       case GL_FOG_START:
 130          if (ctx->Fog.Start == *params)
 131             return;
 132          FLUSH_VERTICES(ctx, _NEW_FOG);
 133          ctx->Fog.Start = *params;
 134          update_fog_scale(ctx);
 135          break;
 136       case GL_FOG_END:
 137          if (ctx->Fog.End == *params)
 138             return;
 139          FLUSH_VERTICES(ctx, _NEW_FOG);
 140          ctx->Fog.End = *params;
 141          update_fog_scale(ctx);
 142          break;
 143       case GL_FOG_INDEX:
 144          if (ctx->API != API_OPENGL_COMPAT)
 145             goto invalid_pname;
 146          if (ctx->Fog.Index == *params)
 147             return;
 148          FLUSH_VERTICES(ctx, _NEW_FOG);
 149          ctx->Fog.Index = *params;
 150          break;
 151       case GL_FOG_COLOR:
 152          if (TEST_EQ_4V(ctx->Fog.Color, params))
 153             return;
 154          FLUSH_VERTICES(ctx, _NEW_FOG);
 155          ctx->Fog.ColorUnclamped[0] = params[0];
 156          ctx->Fog.ColorUnclamped[1] = params[1];
 157          ctx->Fog.ColorUnclamped[2] = params[2];
 158          ctx->Fog.ColorUnclamped[3] = params[3];
 159          ctx->Fog.Color[0] = CLAMP(params[0], 0.0F, 1.0F);
 160          ctx->Fog.Color[1] = CLAMP(params[1], 0.0F, 1.0F);
 161          ctx->Fog.Color[2] = CLAMP(params[2], 0.0F, 1.0F);
 162          ctx->Fog.Color[3] = CLAMP(params[3], 0.0F, 1.0F);
 163          break;
 164       case GL_FOG_COORDINATE_SOURCE_EXT: {
 165          GLenum p = (GLenum) (GLint) *params;
 166          if (ctx->API != API_OPENGL_COMPAT || !ctx->Extensions.EXT_fog_coord ||
 167              (p != GL_FOG_COORDINATE_EXT && p != GL_FRAGMENT_DEPTH_EXT)) {
 168             _mesa_error(ctx, GL_INVALID_ENUM, "glFog");
 169             return;
 170          }
 171          if (ctx->Fog.FogCoordinateSource == p)
 172             return;
 173          FLUSH_VERTICES(ctx, _NEW_FOG);
 174          ctx->Fog.FogCoordinateSource = p;
 175          break;
 176       }
 177       case GL_FOG_DISTANCE_MODE_NV: {
 178          GLenum p = (GLenum) (GLint) *params;
 179          if (ctx->API != API_OPENGL_COMPAT || !ctx->Extensions.NV_fog_distance ||
 180              (p != GL_EYE_RADIAL_NV && p != GL_EYE_PLANE && p != GL_EYE_PLANE_ABSOLUTE_NV)) {
 181             _mesa_error(ctx, GL_INVALID_ENUM, "glFog");
 182             return;
 183          }
 184          if (ctx->Fog.FogDistanceMode == p)
 185             return;
 186          FLUSH_VERTICES(ctx, _NEW_FOG);
 187          ctx->Fog.FogDistanceMode = p;
 188          break;
 189       }
 190       default:
 191          goto invalid_pname;
 192    }
 193
 194    if (ctx->Driver.Fogfv) {
 195       (*ctx->Driver.Fogfv)( ctx, pname, params );
 196    }
 197
 198    return;
 199
 200 invalid_pname:
 201    _mesa_error( ctx, GL_INVALID_ENUM, "glFog" );
 202    return;
 203 }
 204
 205
 206 /**********************************************************************/
 207 /*****                      Initialization                        *****/
 208 /**********************************************************************/
 209
 210 void _mesa_init_fog( struct gl_context * ctx )
 211 {
 212    /* Fog group */
 213    ctx->Fog.Enabled = GL_FALSE;
 214    ctx->Fog.Mode = GL_EXP;
 215    ASSIGN_4V( ctx->Fog.Color, 0.0, 0.0, 0.0, 0.0 );
 216    ASSIGN_4V( ctx->Fog.ColorUnclamped, 0.0, 0.0, 0.0, 0.0 );
 217    ctx->Fog.Index = 0.0;
 218    ctx->Fog.Density = 1.0;
 219    ctx->Fog.Start = 0.0;
 220    ctx->Fog.End = 1.0;
 221    ctx->Fog.ColorSumEnabled = GL_FALSE;
 222    ctx->Fog.FogCoordinateSource = GL_FRAGMENT_DEPTH_EXT;
 223    ctx->Fog._Scale = 1.0f;
 224    ctx->Fog.FogDistanceMode = GL_EYE_PLANE_ABSOLUTE_NV;
 225 }