1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
|
/*
* Mesa 3-D graphics library
* Version: 6.5.2
*
* Copyright (C) 1999-2006 Brian Paul All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include "main/glheader.h"
#include "main/colormac.h"
#include "main/macros.h"
#include "s_context.h"
#include "s_fog.h"
/**
* Used to convert current raster distance to a fog factor in [0,1].
*/
GLfloat
_swrast_z_to_fogfactor(GLcontext *ctx, GLfloat z)
{
GLfloat d, f;
switch (ctx->Fog.Mode) {
case GL_LINEAR:
if (ctx->Fog.Start == ctx->Fog.End)
d = 1.0F;
else
d = 1.0F / (ctx->Fog.End - ctx->Fog.Start);
f = (ctx->Fog.End - z) * d;
return CLAMP(f, 0.0F, 1.0F);
case GL_EXP:
d = ctx->Fog.Density;
f = EXPF(-d * z);
f = CLAMP(f, 0.0F, 1.0F);
return f;
case GL_EXP2:
d = ctx->Fog.Density;
f = EXPF(-(d * d * z * z));
f = CLAMP(f, 0.0F, 1.0F);
return f;
default:
_mesa_problem(ctx, "Bad fog mode in _swrast_z_to_fogfactor");
return 0.0;
}
}
#define LINEAR_FOG(f, coord) f = (fogEnd - coord) * fogScale
#define EXP_FOG(f, coord) f = EXPF(density * coord)
#define EXP2_FOG(f, coord) \
do { \
GLfloat tmp = negDensitySquared * coord * coord; \
if (tmp < FLT_MIN_10_EXP) \
tmp = FLT_MIN_10_EXP; \
f = EXPF(tmp); \
} while(0)
#define BLEND_FOG(f, coord) f = coord
/**
* Template code for computing fog blend factor and applying it to colors.
* \param TYPE either GLubyte, GLushort or GLfloat.
* \param COMPUTE_F code to compute the fog blend factor, f.
*/
#define FOG_LOOP(TYPE, FOG_FUNC) \
if (span->arrayAttribs & FRAG_BIT_FOGC) { \
GLuint i; \
for (i = 0; i < span->end; i++) { \
const GLfloat fogCoord = span->array->attribs[FRAG_ATTRIB_FOGC][i][0]; \
const GLfloat c = FABSF(fogCoord); \
GLfloat f, oneMinusF; \
FOG_FUNC(f, c); \
f = CLAMP(f, 0.0F, 1.0F); \
oneMinusF = 1.0F - f; \
rgba[i][RCOMP] = (TYPE) (f * rgba[i][RCOMP] + oneMinusF * rFog); \
rgba[i][GCOMP] = (TYPE) (f * rgba[i][GCOMP] + oneMinusF * gFog); \
rgba[i][BCOMP] = (TYPE) (f * rgba[i][BCOMP] + oneMinusF * bFog); \
} \
} \
else { \
const GLfloat fogStep = span->attrStepX[FRAG_ATTRIB_FOGC][0]; \
GLfloat fogCoord = span->attrStart[FRAG_ATTRIB_FOGC][0]; \
const GLfloat wStep = span->attrStepX[FRAG_ATTRIB_WPOS][3]; \
GLfloat w = span->attrStart[FRAG_ATTRIB_WPOS][3]; \
GLuint i; \
for (i = 0; i < span->end; i++) { \
const GLfloat c = FABSF(fogCoord) / w; \
GLfloat f, oneMinusF; \
FOG_FUNC(f, c); \
f = CLAMP(f, 0.0F, 1.0F); \
oneMinusF = 1.0F - f; \
rgba[i][RCOMP] = (TYPE) (f * rgba[i][RCOMP] + oneMinusF * rFog); \
rgba[i][GCOMP] = (TYPE) (f * rgba[i][GCOMP] + oneMinusF * gFog); \
rgba[i][BCOMP] = (TYPE) (f * rgba[i][BCOMP] + oneMinusF * bFog); \
fogCoord += fogStep; \
w += wStep; \
} \
}
/**
* Apply fog to a span of RGBA pixels.
* The fog value are either in the span->array->fog array or interpolated from
* the fog/fogStep values.
* They fog values are either fog coordinates (Z) or fog blend factors.
* _PreferPixelFog should be in sync with that state!
*/
void
_swrast_fog_rgba_span( const GLcontext *ctx, SWspan *span )
{
const SWcontext *swrast = CONST_SWRAST_CONTEXT(ctx);
GLfloat rFog, gFog, bFog;
ASSERT(swrast->_FogEnabled);
ASSERT(span->arrayMask & SPAN_RGBA);
/* compute (scaled) fog color */
if (span->array->ChanType == GL_UNSIGNED_BYTE) {
rFog = ctx->Fog.Color[RCOMP] * 255.0F;
gFog = ctx->Fog.Color[GCOMP] * 255.0F;
bFog = ctx->Fog.Color[BCOMP] * 255.0F;
}
else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
rFog = ctx->Fog.Color[RCOMP] * 65535.0F;
gFog = ctx->Fog.Color[GCOMP] * 65535.0F;
bFog = ctx->Fog.Color[BCOMP] * 65535.0F;
}
else {
rFog = ctx->Fog.Color[RCOMP];
gFog = ctx->Fog.Color[GCOMP];
bFog = ctx->Fog.Color[BCOMP];
}
if (swrast->_PreferPixelFog) {
/* The span's fog values are fog coordinates, now compute blend factors
* and blend the fragment colors with the fog color.
*/
switch (swrast->_FogMode) {
case GL_LINEAR:
{
const GLfloat fogEnd = ctx->Fog.End;
const GLfloat fogScale = (ctx->Fog.Start == ctx->Fog.End)
? 1.0F : 1.0F / (ctx->Fog.End - ctx->Fog.Start);
if (span->array->ChanType == GL_UNSIGNED_BYTE) {
GLubyte (*rgba)[4] = span->array->rgba8;
FOG_LOOP(GLubyte, LINEAR_FOG);
}
else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
GLushort (*rgba)[4] = span->array->rgba16;
FOG_LOOP(GLushort, LINEAR_FOG);
}
else {
GLfloat (*rgba)[4] = span->array->attribs[FRAG_ATTRIB_COL0];
ASSERT(span->array->ChanType == GL_FLOAT);
FOG_LOOP(GLfloat, LINEAR_FOG);
}
}
break;
case GL_EXP:
{
const GLfloat density = -ctx->Fog.Density;
if (span->array->ChanType == GL_UNSIGNED_BYTE) {
GLubyte (*rgba)[4] = span->array->rgba8;
FOG_LOOP(GLubyte, EXP_FOG);
}
else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
GLushort (*rgba)[4] = span->array->rgba16;
FOG_LOOP(GLushort, EXP_FOG);
}
else {
GLfloat (*rgba)[4] = span->array->attribs[FRAG_ATTRIB_COL0];
ASSERT(span->array->ChanType == GL_FLOAT);
FOG_LOOP(GLfloat, EXP_FOG);
}
}
break;
case GL_EXP2:
{
const GLfloat negDensitySquared = -ctx->Fog.Density * ctx->Fog.Density;
if (span->array->ChanType == GL_UNSIGNED_BYTE) {
GLubyte (*rgba)[4] = span->array->rgba8;
FOG_LOOP(GLubyte, EXP2_FOG);
}
else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
GLushort (*rgba)[4] = span->array->rgba16;
FOG_LOOP(GLushort, EXP2_FOG);
}
else {
GLfloat (*rgba)[4] = span->array->attribs[FRAG_ATTRIB_COL0];
ASSERT(span->array->ChanType == GL_FLOAT);
FOG_LOOP(GLfloat, EXP2_FOG);
}
}
break;
default:
_mesa_problem(ctx, "Bad fog mode in _swrast_fog_rgba_span");
return;
}
}
else {
/* The span's fog start/step/array values are blend factors in [0,1].
* They were previously computed per-vertex.
*/
if (span->array->ChanType == GL_UNSIGNED_BYTE) {
GLubyte (*rgba)[4] = span->array->rgba8;
FOG_LOOP(GLubyte, BLEND_FOG);
}
else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
GLushort (*rgba)[4] = span->array->rgba16;
FOG_LOOP(GLushort, BLEND_FOG);
}
else {
GLfloat (*rgba)[4] = span->array->attribs[FRAG_ATTRIB_COL0];
ASSERT(span->array->ChanType == GL_FLOAT);
FOG_LOOP(GLfloat, BLEND_FOG);
}
}
}
|
