33 lines
1.0 KiB
Rust
33 lines
1.0 KiB
Rust
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/// Linear interpolation.
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pub fn lerp(a: f32, b: f32, w: f32) -> f32 {
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assert!(0.0 <= w && w <= 1.0);
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a + (b - a) * w
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}
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/// Bilinear interpolation.
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/// Expected order of `p` is from a nested `for` loop with the outer loop being `y`.
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/// `w` is expected to be `[wx, wy]`
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pub fn bi_lerp(p: &[f32], w: &[f32]) -> f32 {
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assert_eq!(p.len(), 4);
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assert_eq!(w.len(), 2);
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lerp(lerp(p[0], p[1], w[0]), lerp(p[2], p[3], w[0]), w[1])
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}
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/// Trilinear interpolation.
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/// Expected order of `p` is from a nested `for` loop with the outer loop being `z`.
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/// `w` is expected to be `[wx, wy, wz]`.
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pub fn tri_lerp(p: &[f32], w: &[f32]) -> f32 {
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assert_eq!(p.len(), 8);
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assert_eq!(w.len(), 3);
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let front = bi_lerp(&[p[0], p[1], p[2], p[3]], &[w[0], w[1]]);
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let back = bi_lerp(&[p[4], p[5], p[6], p[7]], &[w[0], w[1]]);
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lerp(front, back, w[2])
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}
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/// Maps a 3d index to a 1d index
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pub fn to_1d_index(p: glam::UVec3, dim: glam::UVec3) -> usize {
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(p.x + p.y * dim.x + p.z * dim.x * dim.y) as usize
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}
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