Constant HEAD 

pub const HEAD: &str = r#"
struct Post {
    size: vec2<u32>,
    frame: u32,
    seed: u32,
    p0: vec4<f32>,
    p1: vec4<f32>,
    p2: vec4<f32>,
    p3: vec4<f32>,
    region: vec4<u32>,
    extent: vec4<u32>,
}

@group(0) @binding(0) var<uniform> post: Post;
@group(0) @binding(1) var src_tex: texture_2d<f32>;
@group(0) @binding(2) var dst_tex: texture_storage_2d<rgba16float, write>;
"#;