src/mesa/main/fog.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2003  Brian Paul   All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  22  * 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 /**
  83  * Update the gl_fog_attrib::_Scale field.
  84  */
  85 static void
  86 update_fog_scale(struct gl_context *ctx)
  87 {
  88    if (ctx->Fog.End == ctx->Fog.Start)
  89       ctx->Fog._Scale = 1.0f;
  90    else
  91       ctx->Fog._Scale = 1.0f / (ctx->Fog.End - ctx->Fog.Start);
  92 }
  93
  94
  95 void GLAPIENTRY
  96 _mesa_Fogfv( GLenum pname, const GLfloat *params )
  97 {
  98    GET_CURRENT_CONTEXT(ctx);
  99    GLenum m;
 100
 101    switch (pname) {
 102       case GL_FOG_MODE:
 103          m = (GLenum) (GLint) *params;
 104          switch (m) {
 105          case GL_LINEAR:
 106          case GL_EXP:
 107          case GL_EXP2:
 108             break;
 109          default:
 110             _mesa_error( ctx, GL_INVALID_ENUM, "glFog" );
 111             return;
 112          }
 113          if (ctx->Fog.Mode == m)
 114             return;
 115          FLUSH_VERTICES(ctx, _NEW_FOG);
 116          ctx->Fog.Mode = m;
 117          break;
 118       case GL_FOG_DENSITY:
 119          if (*params<0.0) {
 120             _mesa_error( ctx, GL_INVALID_VALUE, "glFog" );
 121             return;
 122          }
 123          if (ctx->Fog.Density == *params)
 124             return;
 125          FLUSH_VERTICES(ctx, _NEW_FOG);
 126          ctx->Fog.Density = *params;
 127          break;
 128       case GL_FOG_START:
 129          if (ctx->Fog.Start == *params)
 130             return;
 131          FLUSH_VERTICES(ctx, _NEW_FOG);
 132          ctx->Fog.Start = *params;
 133          update_fog_scale(ctx);
 134          break;
 135       case GL_FOG_END:
 136          if (ctx->Fog.End == *params)
 137             return;
 138          FLUSH_VERTICES(ctx, _NEW_FOG);
 139          ctx->Fog.End = *params;
 140          update_fog_scale(ctx);
 141          break;
 142       case GL_FOG_INDEX:
 143          if (ctx->API != API_OPENGL_COMPAT)
 144             goto invalid_pname;
 145          if (ctx->Fog.Index == *params)
 146             return;
 147          FLUSH_VERTICES(ctx, _NEW_FOG);
 148          ctx->Fog.Index = *params;
 149          break;
 150       case GL_FOG_COLOR:
 151          if (TEST_EQ_4V(ctx->Fog.Color, params))
 152             return;
 153          FLUSH_VERTICES(ctx, _NEW_FOG);
 154          ctx->Fog.ColorUnclamped[0] = params[0];
 155          ctx->Fog.ColorUnclamped[1] = params[1];
 156          ctx->Fog.ColorUnclamped[2] = params[2];
 157          ctx->Fog.ColorUnclamped[3] = params[3];
 158          ctx->Fog.Color[0] = CLAMP(params[0], 0.0F, 1.0F);
 159          ctx->Fog.Color[1] = CLAMP(params[1], 0.0F, 1.0F);
 160          ctx->Fog.Color[2] = CLAMP(params[2], 0.0F, 1.0F);
 161          ctx->Fog.Color[3] = CLAMP(params[3], 0.0F, 1.0F);
 162          break;
 163       case GL_FOG_COORDINATE_SOURCE_EXT: {
 164          GLenum p = (GLenum) (GLint) *params;
 165          if (ctx->API != API_OPENGL_COMPAT || !ctx->Extensions.EXT_fog_coord ||
 166              (p != GL_FOG_COORDINATE_EXT && p != GL_FRAGMENT_DEPTH_EXT)) {
 167             _mesa_error(ctx, GL_INVALID_ENUM, "glFog");
 168             return;
 169          }
 170          if (ctx->Fog.FogCoordinateSource == p)
 171             return;
 172          FLUSH_VERTICES(ctx, _NEW_FOG);
 173          ctx->Fog.FogCoordinateSource = p;
 174          break;
 175       }
 176       case GL_FOG_DISTANCE_MODE_NV: {
 177          GLenum p = (GLenum) (GLint) *params;
 178          if (ctx->API != API_OPENGL_COMPAT || !ctx->Extensions.NV_fog_distance ||
 179              (p != GL_EYE_RADIAL_NV && p != GL_EYE_PLANE && p != GL_EYE_PLANE_ABSOLUTE_NV)) {
 180             _mesa_error(ctx, GL_INVALID_ENUM, "glFog");
 181             return;
 182          }
 183          if (ctx->Fog.FogDistanceMode == p)
 184             return;
 185          FLUSH_VERTICES(ctx, _NEW_FOG);
 186          ctx->Fog.FogDistanceMode = p;
 187          break;
 188       }
 189       default:
 190          goto invalid_pname;
 191    }
 192
 193    if (ctx->Driver.Fogfv) {
 194       (*ctx->Driver.Fogfv)( ctx, pname, params );
 195    }
 196
 197    return;
 198
 199 invalid_pname:
 200    _mesa_error( ctx, GL_INVALID_ENUM, "glFog" );
 201    return;
 202 }
 203
 204
 205 /**********************************************************************/
 206 /*****                      Initialization                        *****/
 207 /**********************************************************************/
 208
 209 void _mesa_init_fog( struct gl_context * ctx )
 210 {
 211    /* Fog group */
 212    ctx->Fog.Enabled = GL_FALSE;
 213    ctx->Fog.Mode = GL_EXP;
 214    ASSIGN_4V( ctx->Fog.Color, 0.0, 0.0, 0.0, 0.0 );
 215    ASSIGN_4V( ctx->Fog.ColorUnclamped, 0.0, 0.0, 0.0, 0.0 );
 216    ctx->Fog.Index = 0.0;
 217    ctx->Fog.Density = 1.0;
 218    ctx->Fog.Start = 0.0;
 219    ctx->Fog.End = 1.0;
 220    ctx->Fog.ColorSumEnabled = GL_FALSE;
 221    ctx->Fog.FogCoordinateSource = GL_FRAGMENT_DEPTH_EXT;
 222    ctx->Fog._Scale = 1.0f;
 223    ctx->Fog.FogDistanceMode = GL_EYE_PLANE_ABSOLUTE_NV;
 224 }