1#define_import_path bevy_gaussian_splatting::gaussian_3d
2
3#ifdef GAUSSIAN_3D
4#import bevy_gaussian_splatting::bindings::{
5    view,
6    gaussian_uniforms,
7}
8#import bevy_gaussian_splatting::helpers::{
9    cov2d,
10    get_rotation_matrix,
11    get_scale_matrix,
12}
13
14#ifdef PACKED
15    #ifdef PRECOMPUTE_COVARIANCE_3D
16        #import bevy_gaussian_splatting::packed::{
17            get_cov3d,
18        }
19    #else
20        #import bevy_gaussian_splatting::packed::{
21            get_rotation,
22            get_scale,
23        }
24    #endif
25#else ifdef BUFFER_STORAGE
26    #ifdef PRECOMPUTE_COVARIANCE_3D
27        #import bevy_gaussian_splatting::planar::{
28            get_cov3d,
29        }
30    #else
31        #import bevy_gaussian_splatting::planar::{
32            get_rotation,
33            get_scale,
34        }
35    #endif
36#else ifdef BUFFER_TEXTURE
37    #ifdef PRECOMPUTE_COVARIANCE_3D
38        #import bevy_gaussian_splatting::texture::{
39            get_cov3d,
40        }
41    #else
42        #import bevy_gaussian_splatting::texture::{
43            get_rotation,
44            get_scale,
45        }
46    #endif
47#endif
48
49fn compute_cov3d(scale: vec3<f32>, rotation: vec4<f32>) -> array<f32, 6> {
50    let S = get_scale_matrix(scale);
51
52    let T = mat3x3<f32>(
53        gaussian_uniforms.transform[0].xyz,
54        gaussian_uniforms.transform[1].xyz,
55        gaussian_uniforms.transform[2].xyz,
56    );
57
58    let R = get_rotation_matrix(rotation);
59
60    let M = S * R;
61    let Sigma = transpose(M) * M;
62    let TS = T * Sigma * transpose(T);
63
64    return array<f32, 6>(
65        TS[0][0],
66        TS[0][1],
67        TS[0][2],
68        TS[1][1],
69        TS[1][2],
70        TS[2][2],
71    );
72}
73
74fn compute_cov2d_3dgs(
75    position: vec3<f32>,
76    index: u32,
77) -> vec3<f32> {
78#ifdef PRECOMPUTE_COVARIANCE_3D
79    let cov3d = get_cov3d(index);
80#else
81    let rotation = get_rotation(index);
82    let scale = get_scale(index);
83
84    let cov3d = compute_cov3d(scale, rotation);
85#endif
86
87    return cov2d(position, cov3d);
88}
89
90#endif  // GAUSSIAN_3D