36 lines
1.1 KiB
GLSL
36 lines
1.1 KiB
GLSL
layout(location = 0) in vec3 inPos;
|
|
layout(location = 0) out vec4 outColor;
|
|
|
|
layout(binding = 2) uniform samplerCube environmentSampler;
|
|
|
|
const float PI = 3.14159265359;
|
|
|
|
void main() {
|
|
vec3 N = normalize(inPos);
|
|
|
|
vec3 irradiance = vec3(0.0);
|
|
|
|
// tangent space calculation from origin point
|
|
vec3 up = vec3(0.0, 1.0, 0.0);
|
|
vec3 right = cross(up, N);
|
|
up = cross(N, right);
|
|
|
|
float sampleDelta = 0.025;
|
|
float nrSamples = 0.0f;
|
|
for(float phi = 0.0; phi < 2.0 * PI; phi += sampleDelta)
|
|
{
|
|
for(float theta = 0.0; theta < 0.5 * PI; theta += sampleDelta)
|
|
{
|
|
// spherical to cartesian (in tangent space)
|
|
vec3 tangentSample = vec3(sin(theta) * cos(phi), sin(theta) * sin(phi), cos(theta));
|
|
// tangent space to world
|
|
vec3 sampleVec = tangentSample.x * right + tangentSample.y * up + tangentSample.z * N;
|
|
|
|
irradiance += texture(environmentSampler, sampleVec).rgb * cos(theta) * sin(theta);
|
|
nrSamples++;
|
|
}
|
|
}
|
|
irradiance = PI * irradiance * (1.0 / float(nrSamples));
|
|
|
|
outColor = vec4(irradiance, 1.0);
|
|
}
|