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
|
/**
* @file class3/deferred/screenSpaceReflUtil.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
* $/LicenseInfo$
*/
uniform sampler2D depthMap;
uniform sampler2D normalMap;
uniform sampler2D sceneMap;
uniform vec2 screen_res;
uniform mat4 projection_matrix;
uniform float zNear;
uniform float zFar;
uniform mat4 inv_proj;
vec4 getPositionWithDepth(vec2 pos_screen, float depth);
float linearDepth(float depth, float near, float far);
float getDepth(vec2 pos_screen);
float linearDepth01(float d, float znear, float zfar);
float random (vec2 uv) {
return fract(sin(dot(uv, vec2(12.9898, 78.233))) * 43758.5453123); //simple random function
}
// Based off of https://github.com/RoundedGlint585/ScreenSpaceReflection/
// A few tweaks here and there to suit our needs.
vec2 generateProjectedPosition(vec3 pos){
vec4 samplePosition = projection_matrix * vec4(pos, 1.f);
samplePosition.xy = (samplePosition.xy / samplePosition.w) * 0.5 + 0.5;
return samplePosition.xy;
}
bool isBinarySearchEnabled = true;
bool isAdaptiveStepEnabled = true;
bool isExponentialStepEnabled = true;
bool debugDraw = false;
int iterationCount = 40;
float rayStep = 0.1;
float distanceBias = 0.02;
float depthRejectBias = 0.001;
float epsilon = 0.1;
bool traceScreenRay(vec3 position, vec3 reflection, out vec4 hitColor, out float hitDepth, float depth, sampler2D textureFrame) {
vec3 step = rayStep * reflection;
vec3 marchingPosition = position + step;
float delta;
float depthFromScreen;
vec2 screenPosition;
bool hit = false;
hitColor = vec4(0);
int i = 0;
if (depth > depthRejectBias) {
for (; i < iterationCount && !hit; i++) {
screenPosition = generateProjectedPosition(marchingPosition);
depthFromScreen = linearDepth(getDepth(screenPosition), zNear, zFar);
delta = abs(marchingPosition.z) - depthFromScreen;
if (depth < depthFromScreen + epsilon && depth > depthFromScreen - epsilon) {
break;
}
if (abs(delta) < distanceBias) {
vec4 color = vec4(1);
if(debugDraw)
color = vec4( 0.5+ sign(delta)/2,0.3,0.5- sign(delta)/2, 0);
hitColor = texture(textureFrame, screenPosition) * color;
hitDepth = depthFromScreen;
hit = true;
break;
}
if (isBinarySearchEnabled && delta > 0) {
break;
}
if (isAdaptiveStepEnabled){
float directionSign = sign(abs(marchingPosition.z) - depthFromScreen);
//this is sort of adapting step, should prevent lining reflection by doing sort of iterative converging
//some implementation doing it by binary search, but I found this idea more cheaty and way easier to implement
step = step * (1.0 - rayStep * max(directionSign, 0.0));
marchingPosition += step * (-directionSign);
}
else {
marchingPosition += step;
}
if (isExponentialStepEnabled){
step *= 1.05;
}
}
if(isBinarySearchEnabled){
for(; i < iterationCount && !hit; i++){
step *= 0.5;
marchingPosition = marchingPosition - step * sign(delta);
screenPosition = generateProjectedPosition(marchingPosition);
depthFromScreen = linearDepth(getDepth(screenPosition), zNear, zFar);
delta = abs(marchingPosition.z) - depthFromScreen;
if (depth < depthFromScreen + epsilon && depth > depthFromScreen - epsilon) {
break;
}
if (abs(delta) < distanceBias && depthFromScreen != (depth - distanceBias)) {
vec4 color = vec4(1);
if(debugDraw)
color = vec4( 0.5+ sign(delta)/2,0.3,0.5- sign(delta)/2, 0);
hitColor = texture(textureFrame, screenPosition) * color;
hitDepth = depthFromScreen;
hit = true;
break;
}
}
}
}
return hit;
}
|
