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
|
/**
* @file sunLightSSAOF.glsl
* $LicenseInfo:firstyear=2007&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2007, Linden Research, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*/
#extension GL_ARB_texture_rectangle : enable
#ifdef DEFINE_GL_FRAGCOLOR
out vec4 frag_color;
#else
#define frag_color gl_FragColor
#endif
//class 1 -- no shadow, SSAO only
uniform sampler2DRect depthMap;
uniform sampler2DRect normalMap;
uniform sampler2D noiseMap;
// Inputs
uniform float ssao_radius;
uniform float ssao_max_radius;
uniform float ssao_factor;
uniform float ssao_factor_inv;
VARYING vec2 vary_fragcoord;
uniform mat4 inv_proj;
uniform vec2 screen_res;
vec2 encode_normal(vec3 n)
{
float f = sqrt(8 * n.z + 8);
return n.xy / f + 0.5;
}
vec3 decode_normal (vec2 enc)
{
vec2 fenc = enc*4-2;
float f = dot(fenc,fenc);
float g = sqrt(1-f/4);
vec3 n;
n.xy = fenc*g;
n.z = 1-f/2;
return n;
}
vec4 getPosition(vec2 pos_screen)
{
float depth = texture2DRect(depthMap, pos_screen.xy).r;
vec2 sc = pos_screen.xy*2.0;
sc /= screen_res;
sc -= vec2(1.0,1.0);
vec4 ndc = vec4(sc.x, sc.y, 2.0*depth-1.0, 1.0);
vec4 pos = inv_proj * ndc;
pos /= pos.w;
pos.w = 1.0;
return pos;
}
//calculate decreases in ambient lighting when crowded out (SSAO)
float calcAmbientOcclusion(vec4 pos, vec3 norm)
{
float ret = 1.0;
vec2 kern[8];
// exponentially (^2) distant occlusion samples spread around origin
kern[0] = vec2(-1.0, 0.0) * 0.125*0.125;
kern[1] = vec2(1.0, 0.0) * 0.250*0.250;
kern[2] = vec2(0.0, 1.0) * 0.375*0.375;
kern[3] = vec2(0.0, -1.0) * 0.500*0.500;
kern[4] = vec2(0.7071, 0.7071) * 0.625*0.625;
kern[5] = vec2(-0.7071, -0.7071) * 0.750*0.750;
kern[6] = vec2(-0.7071, 0.7071) * 0.875*0.875;
kern[7] = vec2(0.7071, -0.7071) * 1.000*1.000;
vec2 pos_screen = vary_fragcoord.xy;
vec3 pos_world = pos.xyz;
vec2 noise_reflect = texture2D(noiseMap, vary_fragcoord.xy/128.0).xy;
float angle_hidden = 0.0;
int points = 0;
float scale = min(ssao_radius / -pos_world.z, ssao_max_radius);
// it was found that keeping # of samples a constant was the fastest, probably due to compiler optimizations unrolling?)
for (int i = 0; i < 8; i++)
{
vec2 samppos_screen = pos_screen + scale * reflect(kern[i], noise_reflect);
vec3 samppos_world = getPosition(samppos_screen).xyz;
vec3 diff = pos_world - samppos_world;
float dist2 = dot(diff, diff);
// assume each sample corresponds to an occluding sphere with constant radius, constant x-sectional area
// --> solid angle shrinking by the square of distance
//radius is somewhat arbitrary, can approx with just some constant k * 1 / dist^2
//(k should vary inversely with # of samples, but this is taken care of later)
angle_hidden = angle_hidden + float(dot((samppos_world - 0.05*norm - pos_world), norm) > 0.0) * min(1.0/dist2, ssao_factor_inv);
// 'blocked' samples (significantly closer to camera relative to pos_world) are "no data", not "no occlusion"
points = points + int(diff.z > -1.0);
}
angle_hidden = min(ssao_factor*angle_hidden/float(points), 1.0);
ret = (1.0 - (float(points != 0) * angle_hidden));
return min(ret, 1.0);
}
void main()
{
vec2 pos_screen = vary_fragcoord.xy;
//try doing an unproject here
vec4 pos = getPosition(pos_screen);
vec3 norm = texture2DRect(normalMap, pos_screen).xyz;
norm = decode_normal(norm.xy);
frag_color[0] = 1.0;
frag_color[1] = calcAmbientOcclusion(pos, norm);
frag_color[2] = 1.0;
frag_color[3] = 1.0;
}
|
