1#define_import_path bevy_gaussian_splatting::helpers
2
3#import bevy_gaussian_splatting::bindings::{
4    view,
5    gaussian_uniforms,
6}
7
8
9fn intrinsic_matrix() -> mat3x4<f32> {
10    let focal = vec2<f32>(
11        view.clip_from_view.x.x * view.viewport.z / 2.0,
12        view.clip_from_view.y.y * view.viewport.w / 2.0,
13    );
14
15    let Ks = mat3x4<f32>(
16        vec4<f32>(focal.x, 0.0, 0.0, (view.viewport.z - 1.0) / 2.0),
17        vec4<f32>(0.0, focal.y, 0.0, (view.viewport.w - 1.0) / 2.0),
18        vec4<f32>(0.0, 0.0, 0.0, 1.0)
19    );
20
21    return Ks;
22}
23
24
25fn get_rotation_matrix(
26    rotation: vec4<f32>,
27) -> mat3x3<f32> {
28    let r = rotation.x;
29    let x = rotation.y;
30    let y = rotation.z;
31    let z = rotation.w;
32
33    return mat3x3<f32>(
34        1.0 - 2.0 * (y * y + z * z),
35        2.0 * (x * y - r * z),
36        2.0 * (x * z + r * y),
37
38        2.0 * (x * y + r * z),
39        1.0 - 2.0 * (x * x + z * z),
40        2.0 * (y * z - r * x),
41
42        2.0 * (x * z - r * y),
43        2.0 * (y * z + r * x),
44        1.0 - 2.0 * (x * x + y * y),
45    );
46}
47
48
49fn get_scale_matrix(
50    scale: vec3<f32>,
51) -> mat3x3<f32> {
52    return mat3x3<f32>(
53        scale.x * gaussian_uniforms.global_scale, 0.0, 0.0,
54        0.0, scale.y * gaussian_uniforms.global_scale, 0.0,
55        0.0, 0.0, scale.z * gaussian_uniforms.global_scale,
56    );
57}