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