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Split out spot_light_world_from_view into a function in shadows.wgsl (#20050)

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# Objective

- Improve readability

## Solution

- Split a function out

## Testing

- spotlight example works
This commit is contained in:
atlv 2025-07-09 02:05:45 -04:00 committed by GitHub
parent aa87581cce
commit 6fc4bc126d
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1 changed files with 17 additions and 11 deletions
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28
crates/bevy_pbr/src/render/shadows.wgsl
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@ -62,6 +62,22 @@ fn fetch_point_shadow(light_id: u32, frag_position: vec4<f32>, surface_normal: v
return sample_shadow_cubemap(frag_ls * flip_z, distance_to_light, depth, light_id);
}
// this method of constructing a basis from a vec3 is used by glam::Vec3::any_orthonormal_pair
// so we reproduce it here to avoid a mismatch if glam changes. we also switch the handedness
// the construction of the orthonormal basis up and right vectors needs to precisely mirror the code
// in bevy_light/spot_light.rs:spot_light_world_from_view
fn spot_light_world_from_view(fwd: vec3<f32>) -> mat3x3<f32> {
var sign = -1.0;
if (fwd.z >= 0.0) {
sign = 1.0;
}
let a = -1.0 / (fwd.z + sign);
let b = fwd.x * fwd.y * a;
let up_dir = vec3<f32>(1.0 + sign * fwd.x * fwd.x * a, sign * b, -sign * fwd.x);
let right_dir = vec3<f32>(-b, -sign - fwd.y * fwd.y * a, fwd.y);
return mat3x3<f32>(right_dir, up_dir, fwd);
}
fn fetch_spot_shadow(
light_id: u32,
frag_position: vec4<f32>,
@ -88,17 +104,7 @@ fn fetch_spot_shadow(
+ ((*light).shadow_depth_bias * normalize(surface_to_light))
+ (surface_normal.xyz * (*light).shadow_normal_bias) * distance_to_light;
// the construction of the up and right vectors needs to precisely mirror the code
// in render/light.rs:spot_light_view_matrix
var sign = -1.0;
if (fwd.z >= 0.0) {
sign = 1.0;
}
let a = -1.0 / (fwd.z + sign);
let b = fwd.x * fwd.y * a;
let up_dir = vec3<f32>(1.0 + sign * fwd.x * fwd.x * a, sign * b, -sign * fwd.x);
let right_dir = vec3<f32>(-b, -sign - fwd.y * fwd.y * a, fwd.y);
let light_inv_rot = mat3x3<f32>(right_dir, up_dir, fwd);
let light_inv_rot = spot_light_world_from_view(fwd);
// because the matrix is a pure rotation matrix, the inverse is just the transpose, and to calculate
// the product of the transpose with a vector we can just post-multiply instead of pre-multiplying.