lumen-engine 0.2.1

Core composition model and rendering orchestration for Lumen.
Documentation 
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@group(0) @binding(0) var source_tex: texture_2d<f32>;
@group(0) @binding(1) var source_sampler: sampler;

struct VertexOut {
    @builtin(position) position: vec4<f32>,
    @location(0) uv: vec2<f32>,
};

@vertex
fn vs_main(@builtin(vertex_index) vertex_index: u32) -> VertexOut {
    let positions = array<vec2<f32>, 3>(
        vec2<f32>(-1.0, -3.0),
        vec2<f32>(3.0, 1.0),
        vec2<f32>(-1.0, 1.0),
    );
    let position = positions[vertex_index];
    var out: VertexOut;
    out.position = vec4<f32>(position, 0.0, 1.0);
    out.uv = position * vec2<f32>(0.5, -0.5) + vec2<f32>(0.5, 0.5);
    return out;
}

@fragment
fn fs_main(in: VertexOut) -> @location(0) vec4<f32> {
    let pixel = vec2<u32>(floor(in.position.xy));
    let source_size = textureDimensions(source_tex);
    if (pixel.x >= source_size.x || pixel.y >= source_size.y) {
        return vec4<f32>(0.0);
    }
    return textureLoad(source_tex, vec2<i32>(pixel), 0);
}