120 lines
3.4 KiB
Rust
120 lines
3.4 KiB
Rust
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// Multi-language Perlin noise benchmark.
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// See https://github.com/nsf/pnoise for timings and alternative implementations.
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use std::f32::consts::PI;
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use std::rand::{Rng, StdRng};
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struct Vec2 {
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x: f32,
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y: f32,
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}
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fn lerp(a: f32, b: f32, v: f32) -> f32 { a * (1.0 - v) + b * v }
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fn smooth(v: f32) -> f32 { v * v * (3.0 - 2.0 * v) }
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fn random_gradient<R: Rng>(r: &mut R) -> Vec2 {
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let v = PI * 2.0 * r.gen();
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Vec2 { x: v.cos(), y: v.sin() }
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}
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fn gradient(orig: Vec2, grad: Vec2, p: Vec2) -> f32 {
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(p.x - orig.x) * grad.x + (p.y - orig.y) * grad.y
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}
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struct Noise2DContext {
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rgradients: [Vec2, ..256],
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permutations: [i32, ..256],
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}
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impl Noise2DContext {
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fn new() -> Noise2DContext {
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let mut rng = StdRng::new();
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let mut rgradients = [Vec2 { x: 0.0, y: 0.0 }, ..256];
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for x in rgradients.mut_iter() {
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*x = random_gradient(&mut rng);
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}
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let mut permutations = [0i32, ..256];
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for (i, x) in permutations.mut_iter().enumerate() {
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*x = i as i32;
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}
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rng.shuffle_mut(permutations);
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Noise2DContext { rgradients: rgradients, permutations: permutations }
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}
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fn get_gradient(&self, x: i32, y: i32) -> Vec2 {
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let idx = self.permutations[x & 255] + self.permutations[y & 255];
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self.rgradients[idx & 255]
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}
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fn get_gradients(&self, x: f32, y: f32) -> ([Vec2, ..4], [Vec2, ..4]) {
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let x0f = x.floor();
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let y0f = y.floor();
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let x1f = x0f + 1.0;
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let y1f = y0f + 1.0;
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let x0 = x0f as i32;
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let y0 = y0f as i32;
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let x1 = x0 + 1;
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let y1 = y0 + 1;
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([self.get_gradient(x0, y0), self.get_gradient(x1, y0),
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self.get_gradient(x0, y1), self.get_gradient(x1, y1)],
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[Vec2 { x: x0f, y: y0f }, Vec2 { x: x1f, y: y0f },
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Vec2 { x: x0f, y: y1f }, Vec2 { x: x1f, y: y1f }])
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}
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fn get(&self, x: f32, y: f32) -> f32 {
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let p = Vec2 {x: x, y: y};
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let (gradients, origins) = self.get_gradients(x, y);
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let v0 = gradient(origins[0], gradients[0], p);
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let v1 = gradient(origins[1], gradients[1], p);
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let v2 = gradient(origins[2], gradients[2], p);
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let v3 = gradient(origins[3], gradients[3], p);
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let fx = smooth(x - origins[0].x);
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let vx0 = lerp(v0, v1, fx);
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let vx1 = lerp(v2, v3, fx);
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let fy = smooth(y - origins[0].y);
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lerp(vx0, vx1, fy)
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}
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}
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fn main() {
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let symbols = [' ', '░', '▒', '▓', '█', '█'];
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let mut pixels = [0f32, ..256*256];
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let n2d = Noise2DContext::new();
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for _ in range(0, 100) {
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for y in range(0, 256) {
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for x in range(0, 256) {
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let v = n2d.get(x as f32 * 0.1, y as f32 * 0.1);
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pixels[y*256+x] = v * 0.5 + 0.5;
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}
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}
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}
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for y in range(0, 256) {
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for x in range(0, 256) {
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let idx = (pixels[y*256+x] / 0.2) as uint;
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print!("{:c}", symbols[idx]);
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}
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print!("\n");
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}
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}
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