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frustum

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griffi-gh 2023-01-27 21:15:23 +01:00
parent 19fa7e67bc
commit a29f6c65fd
1 changed files with 47 additions and 19 deletions
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66
src/camera/frustum.rs
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@ -7,7 +7,7 @@
// [ http://iquilezles.org/www/articles/frustumcorrect/frustumcorrect.htm ]
// three layers of stolen code, yay!
use glam::{Vec3, Vec4, Vec4Swizzles};
use glam::{Vec3A, Vec4, Mat3A, vec3a};
use super::Camera;
@ -21,12 +21,14 @@ enum FrustumPlane {
Near,
Far,
}
const PLANE_COUNT: usize = 6;
const PLANE_COMBINATIONS: usize = PLANE_COUNT * (PLANE_COUNT - 1) / 2;
const POINT_COUNT: usize = 8;
struct Frustum {
planes: [Vec4; PLANE_COUNT],
crosses: [Vec3; PLANE_COMBINATIONS],
points: [Vec3A; POINT_COUNT]
}
impl Frustum {
pub fn compute(camera: &Camera) -> Self {
@ -44,23 +46,49 @@ impl Frustum {
//compute crosses
let crosses = [
planes[FrustumPlane::Left as usize].xyz().cross(planes[FrustumPlane::Right as usize].xyz()),
planes[FrustumPlane::Left as usize].xyz().cross(planes[FrustumPlane::Bottom as usize].xyz()),
planes[FrustumPlane::Left as usize].xyz().cross(planes[FrustumPlane::Top as usize].xyz()),
planes[FrustumPlane::Left as usize].xyz().cross(planes[FrustumPlane::Near as usize].xyz()),
planes[FrustumPlane::Left as usize].xyz().cross(planes[FrustumPlane::Far as usize].xyz()),
planes[FrustumPlane::Right as usize].xyz().cross(planes[FrustumPlane::Bottom as usize].xyz()),
planes[FrustumPlane::Right as usize].xyz().cross(planes[FrustumPlane::Top as usize].xyz()),
planes[FrustumPlane::Right as usize].xyz().cross(planes[FrustumPlane::Near as usize].xyz()),
planes[FrustumPlane::Right as usize].xyz().cross(planes[FrustumPlane::Far as usize].xyz()),
planes[FrustumPlane::Bottom as usize].xyz().cross(planes[FrustumPlane::Top as usize].xyz()),
planes[FrustumPlane::Bottom as usize].xyz().cross(planes[FrustumPlane::Near as usize].xyz()),
planes[FrustumPlane::Bottom as usize].xyz().cross(planes[FrustumPlane::Far as usize].xyz()),
planes[FrustumPlane::Top as usize].xyz().cross(planes[FrustumPlane::Near as usize].xyz()),
planes[FrustumPlane::Top as usize].xyz().cross(planes[FrustumPlane::Far as usize].xyz()),
planes[FrustumPlane::Near as usize].xyz().cross(planes[FrustumPlane::Far as usize].xyz()),
Vec3A::from(planes[FrustumPlane::Left as usize]).cross(planes[FrustumPlane::Right as usize].into()),
Vec3A::from(planes[FrustumPlane::Left as usize]).cross(planes[FrustumPlane::Bottom as usize].into()),
Vec3A::from(planes[FrustumPlane::Left as usize]).cross(planes[FrustumPlane::Top as usize].into()),
Vec3A::from(planes[FrustumPlane::Left as usize]).cross(planes[FrustumPlane::Near as usize].into()),
Vec3A::from(planes[FrustumPlane::Left as usize]).cross(planes[FrustumPlane::Far as usize].into()),
Vec3A::from(planes[FrustumPlane::Right as usize]).cross(planes[FrustumPlane::Bottom as usize].into()),
Vec3A::from(planes[FrustumPlane::Right as usize]).cross(planes[FrustumPlane::Top as usize].into()),
Vec3A::from(planes[FrustumPlane::Right as usize]).cross(planes[FrustumPlane::Near as usize].into()),
Vec3A::from(planes[FrustumPlane::Right as usize]).cross(planes[FrustumPlane::Far as usize].into()),
Vec3A::from(planes[FrustumPlane::Bottom as usize]).cross(planes[FrustumPlane::Top as usize].into()),
Vec3A::from(planes[FrustumPlane::Bottom as usize]).cross(planes[FrustumPlane::Near as usize].into()),
Vec3A::from(planes[FrustumPlane::Bottom as usize]).cross(planes[FrustumPlane::Far as usize].into()),
Vec3A::from(planes[FrustumPlane::Top as usize]).cross(planes[FrustumPlane::Near as usize].into()),
Vec3A::from(planes[FrustumPlane::Top as usize]).cross(planes[FrustumPlane::Far as usize].into()),
Vec3A::from(planes[FrustumPlane::Near as usize]).cross(planes[FrustumPlane::Far as usize].into()),
];
Self { planes, crosses }
//compute points
let points = [
intersection::<{FrustumPlane::Left as usize}, {FrustumPlane::Bottom as usize}, {FrustumPlane::Near as usize}>(&planes, &crosses),
intersection::<{FrustumPlane::Left as usize}, {FrustumPlane::Top as usize}, {FrustumPlane::Near as usize}>(&planes, &crosses),
intersection::<{FrustumPlane::Right as usize}, {FrustumPlane::Bottom as usize}, {FrustumPlane::Near as usize}>(&planes, &crosses),
intersection::<{FrustumPlane::Right as usize}, {FrustumPlane::Top as usize}, {FrustumPlane::Near as usize}>(&planes, &crosses),
intersection::<{FrustumPlane::Left as usize}, {FrustumPlane::Bottom as usize}, {FrustumPlane::Far as usize}>(&planes, &crosses),
intersection::<{FrustumPlane::Left as usize}, {FrustumPlane::Top as usize}, {FrustumPlane::Far as usize}>(&planes, &crosses),
intersection::<{FrustumPlane::Right as usize}, {FrustumPlane::Bottom as usize}, {FrustumPlane::Far as usize}>(&planes, &crosses),
intersection::<{FrustumPlane::Right as usize}, {FrustumPlane::Top as usize}, {FrustumPlane::Far as usize}>(&planes, &crosses),
];
Self { planes, points }
}
}
const fn ij2k<const I: usize, const J: usize>() -> usize {
I * (9 - I) / 2 + J - 1
}
fn intersection<const A: usize, const B: usize, const C: usize>(planes: &[Vec4; PLANE_COUNT], crosses: &[Vec3A; PLANE_COMBINATIONS]) -> Vec3A {
let d = Vec3A::from(planes[A]).dot(crosses[ij2k::<B, C>()]);
let res = Mat3A::from_cols(
crosses[ij2k::<B, C>()],
crosses[ij2k::<A, C>()],
crosses[ij2k::<A, B>()],
) * vec3a(planes[A].w, planes[B].w, planes[C].w);
res * (-1. / d)
}