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      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 "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    ASSERT_OUTSIDE_BEGIN_END(ctx);
    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)
    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 || !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 || !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 }
    226