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 "context.h"
  28 #include "fog.h"
  29 #include "macros.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 /**
  82  * Update the gl_fog_attrib::_Scale field.
  83  */
  84 static void
  85 update_fog_scale(struct gl_context *ctx)
  86 {
  87    if (ctx->Fog.End == ctx->Fog.Start)
  88       ctx->Fog._Scale = 1.0f;
  89    else
  90       ctx->Fog._Scale = 1.0f / (ctx->Fog.End - ctx->Fog.Start);
  91 }
  92
  93
  94 void GLAPIENTRY
  95 _mesa_Fogfv( GLenum pname, const GLfloat *params )
  96 {
  97    GET_CURRENT_CONTEXT(ctx);
  98    GLenum m;
  99
 100    switch (pname) {
 101       case GL_FOG_MODE:
 102          m = (GLenum) (GLint) *params;
 103          switch (m) {
 104          case GL_LINEAR:
 105          case GL_EXP:
 106          case GL_EXP2:
 107             break;
 108          default:
 109             _mesa_error( ctx, GL_INVALID_ENUM, "glFog" );
 110             return;
 111          }
 112          if (ctx->Fog.Mode == m)
 113             return;
 114          FLUSH_VERTICES(ctx, _NEW_FOG);
 115          ctx->Fog.Mode = m;
 116          break;
 117       case GL_FOG_DENSITY:
 118          if (*params<0.0F) {
 119             _mesa_error( ctx, GL_INVALID_VALUE, "glFog" );
 120             return;
 121          }
 122          if (ctx->Fog.Density == *params)
 123             return;
 124          FLUSH_VERTICES(ctx, _NEW_FOG);
 125          ctx->Fog.Density = *params;
 126          break;
 127       case GL_FOG_START:
 128          if (ctx->Fog.Start == *params)
 129             return;
 130          FLUSH_VERTICES(ctx, _NEW_FOG);
 131          ctx->Fog.Start = *params;
 132          update_fog_scale(ctx);
 133          break;
 134       case GL_FOG_END:
 135          if (ctx->Fog.End == *params)
 136             return;
 137          FLUSH_VERTICES(ctx, _NEW_FOG);
 138          ctx->Fog.End = *params;
 139          update_fog_scale(ctx);
 140          break;
 141       case GL_FOG_INDEX:
 142          if (ctx->API != API_OPENGL_COMPAT)
 143             goto invalid_pname;
 144          if (ctx->Fog.Index == *params)
 145             return;
 146          FLUSH_VERTICES(ctx, _NEW_FOG);
 147          ctx->Fog.Index = *params;
 148          break;
 149       case GL_FOG_COLOR:
 150          if (TEST_EQ_4V(ctx->Fog.Color, params))
 151             return;
 152          FLUSH_VERTICES(ctx, _NEW_FOG);
 153          ctx->Fog.ColorUnclamped[0] = params[0];
 154          ctx->Fog.ColorUnclamped[1] = params[1];
 155          ctx->Fog.ColorUnclamped[2] = params[2];
 156          ctx->Fog.ColorUnclamped[3] = params[3];
 157          ctx->Fog.Color[0] = CLAMP(params[0], 0.0F, 1.0F);
 158          ctx->Fog.Color[1] = CLAMP(params[1], 0.0F, 1.0F);
 159          ctx->Fog.Color[2] = CLAMP(params[2], 0.0F, 1.0F);
 160          ctx->Fog.Color[3] = CLAMP(params[3], 0.0F, 1.0F);
 161          break;
 162       case GL_FOG_COORDINATE_SOURCE_EXT: {
 163          GLenum p = (GLenum) (GLint) *params;
 164          if (ctx->API != API_OPENGL_COMPAT ||
 165              (p != GL_FOG_COORDINATE_EXT && p != GL_FRAGMENT_DEPTH_EXT)) {
 166             _mesa_error(ctx, GL_INVALID_ENUM, "glFog");
 167             return;
 168          }
 169          if (ctx->Fog.FogCoordinateSource == p)
 170             return;
 171          FLUSH_VERTICES(ctx, _NEW_FOG);
 172          ctx->Fog.FogCoordinateSource = p;
 173          break;
 174       }
 175       case GL_FOG_DISTANCE_MODE_NV: {
 176          GLenum p = (GLenum) (GLint) *params;
 177          if (ctx->API != API_OPENGL_COMPAT || !ctx->Extensions.NV_fog_distance ||
 178              (p != GL_EYE_RADIAL_NV && p != GL_EYE_PLANE && p != GL_EYE_PLANE_ABSOLUTE_NV)) {
 179             _mesa_error(ctx, GL_INVALID_ENUM, "glFog");
 180             return;
 181          }
 182          if (ctx->Fog.FogDistanceMode == p)
 183             return;
 184          FLUSH_VERTICES(ctx, _NEW_FOG);
 185          ctx->Fog.FogDistanceMode = p;
 186          break;
 187       }
 188       default:
 189          goto invalid_pname;
 190    }
 191
 192    if (ctx->Driver.Fogfv) {
 193       (*ctx->Driver.Fogfv)( ctx, pname, params );
 194    }
 195
 196    return;
 197
 198 invalid_pname:
 199    _mesa_error( ctx, GL_INVALID_ENUM, "glFog" );
 200    return;
 201 }
 202
 203
 204 /**********************************************************************/
 205 /*****                      Initialization                        *****/
 206 /**********************************************************************/
 207
 208 void _mesa_init_fog( struct gl_context * ctx )
 209 {
 210    /* Fog group */
 211    ctx->Fog.Enabled = GL_FALSE;
 212    ctx->Fog.Mode = GL_EXP;
 213    ASSIGN_4V( ctx->Fog.Color, 0.0, 0.0, 0.0, 0.0 );
 214    ASSIGN_4V( ctx->Fog.ColorUnclamped, 0.0, 0.0, 0.0, 0.0 );
 215    ctx->Fog.Index = 0.0;
 216    ctx->Fog.Density = 1.0;
 217    ctx->Fog.Start = 0.0;
 218    ctx->Fog.End = 1.0;
 219    ctx->Fog.ColorSumEnabled = GL_FALSE;
 220    ctx->Fog.FogCoordinateSource = GL_FRAGMENT_DEPTH_EXT;
 221    ctx->Fog._Scale = 1.0f;
 222    ctx->Fog.FogDistanceMode = GL_EYE_PLANE_ABSOLUTE_NV;
 223 }