35 lines
926 B
GLSL
35 lines
926 B
GLSL
// http://http.developer.nvidia.com/GPUGems3/gpugems3_ch13.html
|
|
// http://developer.download.nvidia.com/SDK/10.5/direct3d/samples.html#VolumeLight
|
|
#version 450
|
|
|
|
#ifdef GL_ES
|
|
precision mediump float;
|
|
#endif
|
|
|
|
uniform sampler2D tex;
|
|
uniform sampler2D gbufferD;
|
|
|
|
in vec2 texCoord;
|
|
out vec4 fragColor;
|
|
|
|
void main() {
|
|
const float decay = 0.96815;
|
|
const float exposure = 0.2;
|
|
const float density = 0.926;
|
|
const float weight = 0.58767;
|
|
const int NUM_SAMPLES = 40;
|
|
vec2 tc = texCoord;
|
|
vec2 lightScreenSpace = vec2(0.3, 0.3);
|
|
vec2 deltaTexCoord = (tc - lightScreenSpace.xy);
|
|
deltaTexCoord *= 1.0 / float(NUM_SAMPLES) * density;
|
|
float illuminationDecay = 1.0;
|
|
vec4 color = texture(tex, tc) * 0.4;
|
|
for (int i = 0; i < NUM_SAMPLES; i++) {
|
|
tc -= deltaTexCoord;
|
|
if (texture(gbufferD, tc).r > 0.99) color += texture(tex, tc) * 0.4;
|
|
color *= illuminationDecay * weight;
|
|
illuminationDecay *= decay;
|
|
}
|
|
fragColor = color;
|
|
}
|