1
2struct Gradient {
3    sky: vec4<f32>,
4    horizon: vec4<f32>,
5    ground: vec4<f32>,
6}
7
8fn render_gradient(r: vec3<f32>, g: Gradient) -> vec3<f32> {
9    let r_norm = normalize(r);
10    let y = r_norm.y;
11
12    let p_sky = max(y, 0f);
13    let p_horizon = 1f-abs(y);
14    let p_ground = max(-y, 0f);
15
16    let color = (g.sky * p_sky) + (g.horizon * p_horizon) + (g.ground * p_ground);
17
18    return color.xyz;
19}
20
21@group(0) @binding(0)
22var<uniform> gradient: Gradient;
23
24@group(1) @binding(0)
25var image: texture_storage_2d_array<rgba16float, write>;
26
27@compute @workgroup_size(8, 8, 1)
28fn main(@builtin(global_invocation_id) invocation_id: vec3<u32>, @builtin(num_workgroups) num_workgroups: vec3<u32>) {
29    let size = textureDimensions(image).x;
30    let scale = f32(size)/2f;
31    
32    let dir = vec2<f32>((f32(invocation_id.x)/scale) - 1f, (f32(invocation_id.y)/scale) - 1f);
33
34    var ray: vec3<f32>;
35    
36    switch invocation_id.z {
37        case 0u {
38            ray = vec3<f32>(1f, -dir.y, -dir.x); // +X
39        }
40        case 1u {
41            ray = vec3<f32>(-1f, -dir.y, dir.x);// -X
42        }
43        case 2u {
44            ray = vec3<f32>(dir.x, 1f, dir.y); // +Y
45        }
46        case 3u {
47            ray = vec3<f32>(dir.x, -1f, -dir.y);// -Y
48        }
49        case 4u {
50            ray = vec3<f32>(dir.x, -dir.y, 1f); // +Z
51        }
52        default: {
53            ray = vec3<f32>(-dir.x, -dir.y, -1f);// -Z
54        }
55    }
56
57    let render = render_gradient(
58        ray,
59        gradient
60    );
61
62    textureStore(
63        image,
64        vec2<i32>(invocation_id.xy),
65        i32(invocation_id.z),
66        vec4<f32>(render, 1.0)
67    );
68}