1#import bevy_pbr::{
2    mesh_view_types::Lights,
3    atmosphere::{
4        types::{Atmosphere, AtmosphereSettings},
5        bindings::{atmosphere, view, settings},
6        functions::{
7            sample_atmosphere, AtmosphereSample,
8            sample_local_inscattering, get_view_position,
9            max_atmosphere_distance, direction_atmosphere_to_world,
10            sky_view_lut_uv_to_zenith_azimuth, zenith_azimuth_to_ray_dir,
11            MIDPOINT_RATIO, raymarch_atmosphere, EPSILON
12        },
13    }
14}
15
16#import bevy_render::{
17    view::View,
18    maths::HALF_PI,
19}
20#import bevy_core_pipeline::fullscreen_vertex_shader::FullscreenVertexOutput
21
22@group(0) @binding(13) var sky_view_lut_out: texture_storage_2d<rgba16float, write>;
23
24@compute
25@workgroup_size(16, 16, 1)
26fn main(@builtin(global_invocation_id) idx: vec3<u32>) {
27    let uv = vec2<f32>(idx.xy) / vec2<f32>(settings.sky_view_lut_size);
28
29    let cam_pos = get_view_position();
30    let r = length(cam_pos);
31    var zenith_azimuth = sky_view_lut_uv_to_zenith_azimuth(r, uv);
32
33    let ray_dir_as = zenith_azimuth_to_ray_dir(zenith_azimuth.x, zenith_azimuth.y);
34    let ray_dir_ws = direction_atmosphere_to_world(ray_dir_as);
35
36    let world_pos = vec3(0.0, r, 0.0);
37    let up = normalize(world_pos);
38    let mu = dot(ray_dir_ws, up);
39    let t_max = max_atmosphere_distance(r, mu);
40
41    let result = raymarch_atmosphere(world_pos, ray_dir_ws, t_max, settings.sky_view_lut_samples, uv, true);
42
43    textureStore(sky_view_lut_out, idx.xy, vec4(result.inscattering, 1.0));
44}