fog.c revision 848b8605 
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
35void 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
45void 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
55void 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 */
85static void
86update_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
95void 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 ||
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
199invalid_pname:
200   _mesa_error( ctx, GL_INVALID_ENUM, "glFog" );
201   return;
202}
203
204
205/**********************************************************************/
206/*****                      Initialization                        *****/
207/**********************************************************************/
208
209void _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}
225