lumen-engine 0.2.2

Core composition model and rendering orchestration for Lumen.
Documentation 
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struct ExposureParams {
    exposure: f32,
    contrast: f32,
    offset: f32,
    _pad: f32,
}

@group(0) @binding(0) var input_tex: texture_2d<f32>;
@group(0) @binding(1) var<uniform> params: ExposureParams;
@group(0) @binding(2) var output_tex: texture_storage_2d<rgba8unorm, write>;

@compute @workgroup_size(8, 8, 1)
fn cs_main(@builtin(global_invocation_id) id: vec3<u32>) {
    let size = textureDimensions(output_tex);
    if (id.x >= size.x || id.y >= size.y) {
        return;
    }

    let color = textureLoad(input_tex, vec2<i32>(id.xy), 0);
    let exposure_gain = exp2(params.exposure);
    let rgb = clamp(((color.rgb * exposure_gain) + vec3<f32>(params.offset) - vec3<f32>(0.5)) * params.contrast + vec3<f32>(0.5), vec3<f32>(0.0), vec3<f32>(1.0));
    textureStore(output_tex, vec2<i32>(id.xy), vec4<f32>(rgb, color.a));
}