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
|
/* Copy the depth only shadowmap into another texture while converting
* to linear depth (or other storage method) and doing a 3x3 box filter. */
layout(std140) uniform shadow_render_block
{
/* Use vectors to avoid alignement padding. */
ivec4 shadowSampleCount;
vec4 shadowInvSampleCount;
vec4 filterSize;
int viewCount;
int baseId;
float cubeTexelSize;
float storedTexelSize;
float nearClip;
float farClip;
float exponent;
};
#ifdef CSM
uniform sampler2DArray shadowTexture;
#else
uniform samplerCube shadowTexture;
#endif
flat in int layerID;
#ifdef CSM
# define cascadeID layerID
#else
# define cascadeID 0
#endif
out vec4 FragColor;
#define linear_depth(z) \
((nearClip * farClip) / (clamp(z, 0.0, 0.999999) * (nearClip - farClip) + farClip))
/* add bias so background filtering does not bleed into shadow map */
#define BACKGROUND_BIAS 0.05
#ifdef CSM
vec4 get_world_distance(vec4 depths, vec3 cos[4])
{
depths += step(vec4(0.9999), depths) * BACKGROUND_BIAS;
return clamp(
depths * abs(farClip - nearClip), 0.0, 1e10); /* Same factor as in shadow_cascade(). */
}
float get_world_distance(float depth, vec3 cos)
{
depth += step(0.9999, depth) * BACKGROUND_BIAS;
return clamp(
depth * abs(farClip - nearClip), 0.0, 1e10); /* Same factor as in shadow_cascade(). */
}
#else /* CUBEMAP */
vec4 get_world_distance(vec4 depths, vec3 cos[4])
{
depths = linear_depth(depths);
cos[0] = normalize(abs(cos[0]));
cos[1] = normalize(abs(cos[1]));
cos[2] = normalize(abs(cos[2]));
cos[3] = normalize(abs(cos[3]));
vec4 cos_vec;
cos_vec.x = max(cos[0].x, max(cos[0].y, cos[0].z));
cos_vec.y = max(cos[1].x, max(cos[1].y, cos[1].z));
cos_vec.z = max(cos[2].x, max(cos[2].y, cos[2].z));
cos_vec.w = max(cos[3].x, max(cos[3].y, cos[3].z));
return depths / cos_vec;
}
float get_world_distance(float depth, vec3 cos)
{
depth = linear_depth(depth);
cos = normalize(abs(cos));
float cos_vec = max(cos.x, max(cos.y, cos.z));
return depth / cos_vec;
}
#endif
/* Marco Salvi's GDC 2008 presentation about shadow maps pre-filtering techniques slide 24 */
#define ln_space_prefilter_step(ref, sample) exp(sample - ref)
#define ln_space_prefilter_finalize(ref, sum) (ref + log(SAMPLE_WEIGHT * sum))
#define SAMPLE_WEIGHT 0.11111
#ifdef ESM
void prefilter(vec4 depths, float ref, inout float accum)
{
accum += dot(ln_space_prefilter_step(ref, depths), vec4(1.0));
}
#else /* VSM */
void prefilter(vec4 depths, float ref, inout vec2 accum)
{
vec4 depths_sqr = depths * depths;
accum += vec2(dot(vec4(1.0), depths), dot(vec4(1.0), depths_sqr)) * SAMPLE_WEIGHT;
}
#endif
#ifdef CSM
vec3 get_texco(vec2 uvs, vec2 ofs)
{
return vec3(uvs + ofs, float(cascadeID));
}
#else /* CUBEMAP */
const vec3 minorAxisX[6] = vec3[6](vec3(0.0f, 0.0f, -1.0f),
vec3(0.0f, 0.0f, 1.0f),
vec3(1.0f, 0.0f, 0.0f),
vec3(1.0f, 0.0f, 0.0f),
vec3(1.0f, 0.0f, 0.0f),
vec3(-1.0f, 0.0f, 0.0f));
const vec3 minorAxisY[6] = vec3[6](vec3(0.0f, -1.0f, 0.0f),
vec3(0.0f, -1.0f, 0.0f),
vec3(0.0f, 0.0f, 1.0f),
vec3(0.0f, 0.0f, -1.0f),
vec3(0.0f, -1.0f, 0.0f),
vec3(0.0f, -1.0f, 0.0f));
const vec3 majorAxis[6] = vec3[6](vec3(1.0f, 0.0f, 0.0f),
vec3(-1.0f, 0.0f, 0.0f),
vec3(0.0f, 1.0f, 0.0f),
vec3(0.0f, -1.0f, 0.0f),
vec3(0.0f, 0.0f, 1.0f),
vec3(0.0f, 0.0f, -1.0f));
vec3 get_texco(vec2 uvs, vec2 ofs)
{
uvs += ofs;
return majorAxis[layerID] + uvs.x * minorAxisX[layerID] + uvs.y * minorAxisY[layerID];
}
#endif
void main()
{
/* Copy the depth only shadowmap into another texture while converting
* to linear depth and do a 3x3 box blur. */
#ifdef CSM
vec2 uvs = gl_FragCoord.xy * storedTexelSize;
#else /* CUBEMAP */
vec2 uvs = gl_FragCoord.xy * cubeTexelSize * 2.0 - 1.0;
#endif
/* Center texel */
vec3 co = get_texco(uvs, vec2(0.0));
float depth = texture(shadowTexture, co).r;
depth = get_world_distance(depth, co);
if (filterSize[cascadeID] == 0.0) {
#ifdef ESM
FragColor = vec4(depth);
#else /* VSM */
FragColor = vec2(depth, depth * depth).xyxy;
#endif
return;
}
#ifdef ESM
float ref = depth;
float accum = 1.0;
#else /* VSM */
float ref = 0.0; /* UNUSED */
vec2 accum = vec2(depth, depth * depth) * SAMPLE_WEIGHT;
#endif
vec3 ofs = vec3(1.0, 0.0, -1.0) * filterSize[cascadeID];
vec3 cos[4];
cos[0] = get_texco(uvs, ofs.zz);
cos[1] = get_texco(uvs, ofs.yz);
cos[2] = get_texco(uvs, ofs.xz);
cos[3] = get_texco(uvs, ofs.zy);
vec4 depths;
depths.x = texture(shadowTexture, cos[0]).r;
depths.y = texture(shadowTexture, cos[1]).r;
depths.z = texture(shadowTexture, cos[2]).r;
depths.w = texture(shadowTexture, cos[3]).r;
depths = get_world_distance(depths, cos);
prefilter(depths, ref, accum);
cos[0] = get_texco(uvs, ofs.xy);
cos[1] = get_texco(uvs, ofs.zx);
cos[2] = get_texco(uvs, ofs.yx);
cos[3] = get_texco(uvs, ofs.xx);
depths.x = texture(shadowTexture, cos[0]).r;
depths.y = texture(shadowTexture, cos[1]).r;
depths.z = texture(shadowTexture, cos[2]).r;
depths.w = texture(shadowTexture, cos[3]).r;
depths = get_world_distance(depths, cos);
prefilter(depths, ref, accum);
#ifdef ESM
accum = ln_space_prefilter_finalize(ref, accum);
#endif
/* Clamp infinite sum. */
FragColor = vec2(clamp(accum, 0.0, 1e16)).xyxy;
}
|
