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
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   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
200invalid_pname:
201   _mesa_error( ctx, GL_INVALID_ENUM, "glFog" );
202   return;
203}
204
205
206/**********************************************************************/
207/*****                      Initialization                        *****/
208/**********************************************************************/
209
210void _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