fog.c revision 7117f1b4 
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 "mtypes.h"
31
32
33
34void GLAPIENTRY
35_mesa_Fogf(GLenum pname, GLfloat param)
36{
37   _mesa_Fogfv(pname, &param);
38}
39
40
41void GLAPIENTRY
42_mesa_Fogi(GLenum pname, GLint param )
43{
44   GLfloat fparam = (GLfloat) param;
45   _mesa_Fogfv(pname, &fparam);
46}
47
48
49void GLAPIENTRY
50_mesa_Fogiv(GLenum pname, const GLint *params )
51{
52   GLfloat p[4];
53   switch (pname) {
54      case GL_FOG_MODE:
55      case GL_FOG_DENSITY:
56      case GL_FOG_START:
57      case GL_FOG_END:
58      case GL_FOG_INDEX:
59      case GL_FOG_COORDINATE_SOURCE_EXT:
60	 p[0] = (GLfloat) *params;
61	 break;
62      case GL_FOG_COLOR:
63	 p[0] = INT_TO_FLOAT( params[0] );
64	 p[1] = INT_TO_FLOAT( params[1] );
65	 p[2] = INT_TO_FLOAT( params[2] );
66	 p[3] = INT_TO_FLOAT( params[3] );
67	 break;
68      default:
69         /* Error will be caught later in _mesa_Fogfv */
70         ;
71   }
72   _mesa_Fogfv(pname, p);
73}
74
75
76#define UPDATE_FOG_SCALE(ctx) do {\
77      if (ctx->Fog.End == ctx->Fog.Start)\
78         ctx->Fog._Scale = 1.0f;\
79      else\
80         ctx->Fog._Scale = 1.0f / (ctx->Fog.End - ctx->Fog.Start);\
81   } while(0)
82
83
84void GLAPIENTRY
85_mesa_Fogfv( GLenum pname, const GLfloat *params )
86{
87   GET_CURRENT_CONTEXT(ctx);
88   GLenum m;
89   ASSERT_OUTSIDE_BEGIN_END(ctx);
90
91   switch (pname) {
92      case GL_FOG_MODE:
93         m = (GLenum) (GLint) *params;
94	 switch (m) {
95	 case GL_LINEAR:
96	 case GL_EXP:
97	 case GL_EXP2:
98	    break;
99	 default:
100	    _mesa_error( ctx, GL_INVALID_ENUM, "glFog" );
101            return;
102	 }
103	 if (ctx->Fog.Mode == m)
104	    return;
105	 FLUSH_VERTICES(ctx, _NEW_FOG);
106	 ctx->Fog.Mode = m;
107	 break;
108      case GL_FOG_DENSITY:
109	 if (*params<0.0) {
110	    _mesa_error( ctx, GL_INVALID_VALUE, "glFog" );
111            return;
112	 }
113	 if (ctx->Fog.Density == *params)
114	    return;
115	 FLUSH_VERTICES(ctx, _NEW_FOG);
116	 ctx->Fog.Density = *params;
117	 break;
118      case GL_FOG_START:
119         if (ctx->Fog.Start == *params)
120            return;
121         FLUSH_VERTICES(ctx, _NEW_FOG);
122         ctx->Fog.Start = *params;
123         UPDATE_FOG_SCALE(ctx);
124         break;
125      case GL_FOG_END:
126         if (ctx->Fog.End == *params)
127            return;
128         FLUSH_VERTICES(ctx, _NEW_FOG);
129         ctx->Fog.End = *params;
130         UPDATE_FOG_SCALE(ctx);
131         break;
132      case GL_FOG_INDEX:
133 	 if (ctx->Fog.Index == *params)
134	    return;
135	 FLUSH_VERTICES(ctx, _NEW_FOG);
136 	 ctx->Fog.Index = *params;
137	 break;
138      case GL_FOG_COLOR:
139	 if (TEST_EQ_4V(ctx->Fog.Color, params))
140	    return;
141	 FLUSH_VERTICES(ctx, _NEW_FOG);
142	 ctx->Fog.Color[0] = CLAMP(params[0], 0.0F, 1.0F);
143	 ctx->Fog.Color[1] = CLAMP(params[1], 0.0F, 1.0F);
144	 ctx->Fog.Color[2] = CLAMP(params[2], 0.0F, 1.0F);
145	 ctx->Fog.Color[3] = CLAMP(params[3], 0.0F, 1.0F);
146         break;
147      case GL_FOG_COORDINATE_SOURCE_EXT: {
148	 GLenum p = (GLenum) (GLint) *params;
149         if (!ctx->Extensions.EXT_fog_coord ||
150             (p != GL_FOG_COORDINATE_EXT && p != GL_FRAGMENT_DEPTH_EXT)) {
151	    _mesa_error(ctx, GL_INVALID_ENUM, "glFog");
152	    return;
153	 }
154	 if (ctx->Fog.FogCoordinateSource == p)
155	    return;
156	 FLUSH_VERTICES(ctx, _NEW_FOG);
157	 ctx->Fog.FogCoordinateSource = p;
158	 break;
159      }
160      default:
161         _mesa_error( ctx, GL_INVALID_ENUM, "glFog" );
162         return;
163   }
164
165   if (ctx->Driver.Fogfv) {
166      (*ctx->Driver.Fogfv)( ctx, pname, params );
167   }
168}
169
170
171/**********************************************************************/
172/*****                      Initialization                        *****/
173/**********************************************************************/
174
175void _mesa_init_fog( GLcontext * ctx )
176{
177   /* Fog group */
178   ctx->Fog.Enabled = GL_FALSE;
179   ctx->Fog.Mode = GL_EXP;
180   ASSIGN_4V( ctx->Fog.Color, 0.0, 0.0, 0.0, 0.0 );
181   ctx->Fog.Index = 0.0;
182   ctx->Fog.Density = 1.0;
183   ctx->Fog.Start = 0.0;
184   ctx->Fog.End = 1.0;
185   ctx->Fog.ColorSumEnabled = GL_FALSE;
186   ctx->Fog.FogCoordinateSource = GL_FRAGMENT_DEPTH_EXT;
187   ctx->Fog._Scale = 1.0f;
188}
189