1#import bevy_pbr::mesh_view_bindings::view
2#import bevy_pbr::mesh_functions::get_world_from_local
3
4#import bevy_pbr::forward_io::Vertex
5
6struct VertexOutput {
7    @builtin(position) clip_position: vec4<f32>,
8    @location(0) height: f32,
9};
10
11@vertex
12fn vertex(vertex: Vertex) -> VertexOutput {
13    var out: VertexOutput;
14    let model_matrix = get_world_from_local(vertex.instance_index);
15    let world_position = model_matrix * vec4<f32>(vertex.position, 1.0);
16
17    out.clip_position = view.clip_from_world * world_position;
18
19    out.height = vertex.position.y;
20
21    return out;
22}
23
24struct HeightSettings {
25    min_height: f32,
26    max_height: f32,
27};
28
29@group(3) @binding(0)
30var<uniform> settings: HeightSettings;
31
32@fragment
33fn fragment(in: VertexOutput) -> @location(0) vec4<f32> {
34    let span = settings.max_height - settings.min_height;
35
36    if (span <= 0.0) {
37        return vec4<f32>(0.0, 0.0, 0.0, 1.0);
38    }
39
40    let normalized_height = (in.height - settings.min_height) / span;
41
42    return vec4<f32>(normalized_height, 0.0, 0.0, 1.0);
43}