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voxel-rs
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Inline math functions, optimise trilerp

This commit is contained in:
Jarrod Doyle 2023-05-09 20:09:32 +01:00
parent 7e6746a8cd
commit dc205d24ef
Signed by: Jayrude
GPG Key ID: 38B57B16E7C0ADF7
1 changed files with 10 additions and 3 deletions
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13
src/math.rs
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@ -1,4 +1,5 @@
/// Linear interpolation.
#[inline]
pub fn lerp(a: f32, b: f32, w: f32) -> f32 {
assert!(0.0 <= w && w <= 1.0);
a + (b - a) * w
@ -7,6 +8,7 @@ pub fn lerp(a: f32, b: f32, w: f32) -> f32 {
/// Bilinear interpolation.
/// Expected order of `p` is from a nested `for` loop with the outer loop being `y`.
/// `w` is expected to be `[wx, wy]`
#[inline]
pub fn bi_lerp(p: &[f32], w: &[f32]) -> f32 {
assert_eq!(p.len(), 4);
assert_eq!(w.len(), 2);
@ -17,13 +19,18 @@ pub fn bi_lerp(p: &[f32], w: &[f32]) -> f32 {
/// Trilinear interpolation.
/// Expected order of `p` is from a nested `for` loop with the outer loop being `z`.
/// `w` is expected to be `[wx, wy, wz]`.
#[inline]
pub fn tri_lerp(p: &[f32], w: &[f32]) -> f32 {
assert_eq!(p.len(), 8);
assert_eq!(w.len(), 3);
let front = bi_lerp(&[p[0], p[1], p[2], p[3]], &[w[0], w[1]]);
let back = bi_lerp(&[p[4], p[5], p[6], p[7]], &[w[0], w[1]]);
lerp(front, back, w[2])
let c00 = p[0] + (p[1] - p[0]) * w[0];
let c10 = p[2] + (p[3] - p[2]) * w[0];
let c01 = p[4] + (p[5] - p[4]) * w[0];
let c11 = p[6] + (p[7] - p[6]) * w[0];
let c0 = c00 + (c10 - c00) * w[1];
let c1 = c01 + (c11 - c01) * w[1];
c0 + (c1 - c0) * w[2]
}
/// Maps a 3d index to a 1d index