1#define_import_path bevy_gaussian_splatting::gaussian_3d
2
3
4#ifdef GAUSSIAN_3D
5#import bevy_gaussian_splatting::bindings::{
6    view,
7    gaussian_uniforms,
8}
9#import bevy_gaussian_splatting::helpers::{
10    cov2d,
11    get_rotation_matrix,
12    get_scale_matrix,
13}
14
15
16#ifdef PACKED
17    #ifdef PRECOMPUTE_COVARIANCE_3D
18        #import bevy_gaussian_splatting::packed::{
19            get_cov3d,
20        }
21    #else
22        #import bevy_gaussian_splatting::packed::{
23            get_rotation,
24            get_scale,
25        }
26    #endif
27#else ifdef BUFFER_STORAGE
28    #ifdef PRECOMPUTE_COVARIANCE_3D
29        #import bevy_gaussian_splatting::planar::{
30            get_cov3d,
31        }
32    #else
33        #import bevy_gaussian_splatting::planar::{
34            get_rotation,
35            get_scale,
36        }
37    #endif
38#else ifdef BUFFER_TEXTURE
39    #ifdef PRECOMPUTE_COVARIANCE_3D
40        #import bevy_gaussian_splatting::texture::{
41            get_cov3d,
42        }
43    #else
44        #import bevy_gaussian_splatting::texture::{
45            get_rotation,
46            get_scale,
47        }
48    #endif
49#endif
50
51
52fn compute_cov3d(scale: vec3<f32>, rotation: vec4<f32>) -> array<f32, 6> {
53    let S = get_scale_matrix(scale);
54
55    let T = mat3x3<f32>(
56        gaussian_uniforms.transform[0].xyz,
57        gaussian_uniforms.transform[1].xyz,
58        gaussian_uniforms.transform[2].xyz,
59    );
60
61    let R = get_rotation_matrix(rotation);
62
63    let M = S * R;
64    let Sigma = transpose(M) * M;
65    let TS = T * Sigma * transpose(T);
66
67    return array<f32, 6>(
68        TS[0][0],
69        TS[0][1],
70        TS[0][2],
71        TS[1][1],
72        TS[1][2],
73        TS[2][2],
74    );
75}
76
77fn compute_cov2d_3dgs(
78    position: vec3<f32>,
79    index: u32,
80) -> vec3<f32> {
81#ifdef PRECOMPUTE_COVARIANCE_3D
82    let cov3d = get_cov3d(index);
83#else
84    let rotation = get_rotation(index);
85    let scale = get_scale(index);
86
87    let cov3d = compute_cov3d(scale, rotation);
88#endif
89
90    return cov2d(position, cov3d);
91}
92
93#endif  // GAUSSIAN_3D