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ursus_core/math/
light_frustum.rs

1use glam::camera::rh::proj::vulkan::orthographic;
2use glam::camera::rh::view::look_at_mat4;
3
4pub fn compute_light_view_proj(direction: [f32; 3], scene_center: glam::Vec3, scene_radius: f32) -> glam::Mat4 {
5    let dir = glam::Vec3::from(direction).normalize();
6    let light_pos = scene_center - dir * scene_radius;
7
8    let up = [glam::Vec3::Y, glam::Vec3::Z, glam::Vec3::X]
9        .iter()
10        .find(|&&u| dir.cross(u).length() > 0.01)
11        .copied()
12        .unwrap_or(glam::Vec3::Y);
13
14    let view = look_at_mat4(light_pos, scene_center, up);
15    let ortho = orthographic(-scene_radius, scene_radius, -scene_radius, scene_radius, 0.1, scene_radius * 2.0);
16    ortho * view
17}