forestiles/src/shader.wgsl

struct Uniforms {
    camera: vec2f,
    zooms: vec2f
}
@group(0) @binding(0) var<uniform> uniforms : Uniforms;

struct VertexOutput {
    @location(0) color: vec4f,
    @builtin(position) pos: vec4f
}

@vertex
fn vs_main(
    @location(0) pos: vec2f,
    @location(1) color: vec4f,
    @location(2) effect: u32
) -> VertexOutput {
    var out: VertexOutput;
    switch effect {
        case 1u, 3u: {
            var v = (color.r*0.299) + (color.g*0.587) + (color.b*0.114);
            out.color = vec4f(v, v, v, color.a);
        }
        case 0u, 2u: {
            out.color = color;
        }
        default: {}
    }
    switch effect {
        case 0u, 1u: {
            out.pos = vec4f(pos, 0, 1);
        }
        case 2u, 3u: {
            out.pos = vec4f((pos - uniforms.camera) * uniforms.zooms, 0, 1);
        }
        default: {}
    }
    return out;
}

@fragment
fn fs_main(v: VertexOutput) -> @location(0) vec4f {
    return v.color;
}