NazaraEngine/assets/shaders/god_rays.nzsl

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[nzsl_version("1.0")]
module;
import VertOut, VertexShader from Engine.FullscreenVertex;
import ViewerData from Engine.ViewerData;
[layout(std140)]
struct Settings
{
exposure: f32,
decay: f32,
density: f32,
weight: f32,
lightPosition: vec2[f32], //< TODO: Switch to world position
}
const SampleCount: i32 = 200;
external
{
[set(0), binding(0)] viewerData: uniform[ViewerData],
[set(0), binding(1)] settings: uniform[Settings],
[set(0), binding(2)] occluderTexture: sampler2D[f32]
}
struct FragOut
{
[location(0)] color: vec4[f32]
}
[entry(frag)]
fn main(input: VertOut) -> FragOut
{
let deltaUV = input.uv - settings.lightPosition;
deltaUV *= 1.0 / f32(SampleCount) * settings.density;
let illuminationDecay = 1.0;
let uv = input.uv;
let outputColor = vec4[f32](0.0, 0.0, 0.0, 1.0);
for i in 0 -> SampleCount
{
uv -= deltaUV;
let sample = occluderTexture.Sample(uv);
sample *= illuminationDecay * settings.weight;
outputColor += sample;
illuminationDecay *= settings.decay;
}
let output: FragOut;
output.color = outputColor;
return output;
}