#spline #spline-interpolation

nd_interpolate

1-10 dimensional linear and cubic spline interpolation implemented in Rust

1 stable release

2.0.2 Jul 12, 2023

#395 in Simulation

MIT license

28KB
206 lines

ND-Interpolate-rs

1-10 dimensional interpolation implemented in Rust. It supports both f64 and f32 data types for interpolation, and has both linear and cubic spline interpolation for up to 10 dimensions.

This library is particularly useful for Perlin Noise applications.

Example

Here's an example of using 3D cubic interpolation to make a marble-pattern texture for a sphere:

use nd_interpolate::*;
use image::*; // image = "0.23.14"
use rand::prelude::*; // rand = "0.8.4"
use std::f64::consts::PI;

fn sphere_marble_texture_example() {
	println!("Making marbled sphere texture...");
	let imgsize = 512; let w = 2*imgsize; let h = imgsize;
	let gridsize = 16; let gridcenter = gridsize / 2;
	let radius = (gridsize / 2 - 3) as f64;
	let mut img: RgbImage = ImageBuffer::new(w, h);
	let mut rand_grid = vec![vec![vec![0f64;gridsize];gridsize];gridsize];
	for x in 0..rand_grid.len(){ for y in 0..rand_grid[x].len(){ for z in 0..rand_grid[x][y].len() {
		let r: f64 = random();
		rand_grid[x][y][z] = r;
	} } }
	for py in 0..h { for px in 0..w {
		let lon = (px as f64 / w as f64) * (2.0*PI) - PI;
		let lat = ((h-py) as f64 / h as f64) * PI - 0.5*PI;
		let coord = [
			radius * lon.sin() * lat.cos(), // X
			radius * lat.sin(), // Y
			radius * lon.cos() * lat.cos(), // Z
		];
		let grid_coord: [usize; 3] = [
			(coord[0].floor() as i32 + gridcenter as i32) as usize,
			(coord[1].floor() as i32 + gridcenter as i32) as usize,
			(coord[2].floor() as i32 + gridcenter as i32) as usize
		];
		let mut local_4x4x4 = [[[0f64;4];4];4];
		for ix in 0..4{for iy in 0..4{for iz in 0..4{
			let gx = grid_coord[0];
			let gy = grid_coord[1];
			let gz = grid_coord[2];
			local_4x4x4[ix][iy][iz] = rand_grid[ix+gx-1][iy+gy-1][iz+gz-1];
		}}}
		let v = ((cubic_3D_grid(coord, &local_4x4x4)) * 255f64) as u8;
		let pixel = Rgb([v,v,v]);
		img.put_pixel(px, py, pixel);
	} }
	img.save("marbled_sphere_texture.png").unwrap();
	println!("...Done!");
}

The above code produced the following image: 3D_cubic_image_interpolation

Notes

This Rust library is based on my Java noise library interpolator

Dependencies

~150KB