1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 // Multi-language Perlin noise benchmark.
12 // See https://github.com/nsf/pnoise for timings and alternative implementations.
13 // ignore-lexer-test FIXME #15679
15 use std::f32::consts::PI;
16 use std::rand::{Rng, StdRng};
23 fn lerp(a: f32, b: f32, v: f32) -> f32 { a * (1.0 - v) + b * v }
25 fn smooth(v: f32) -> f32 { v * v * (3.0 - 2.0 * v) }
27 fn random_gradient<R: Rng>(r: &mut R) -> Vec2 {
28 let v = PI * 2.0 * r.gen();
29 Vec2 { x: v.cos(), y: v.sin() }
32 fn gradient(orig: Vec2, grad: Vec2, p: Vec2) -> f32 {
33 (p.x - orig.x) * grad.x + (p.y - orig.y) * grad.y
36 struct Noise2DContext {
37 rgradients: [Vec2, ..256],
38 permutations: [i32, ..256],
42 fn new() -> Noise2DContext {
43 let mut rng = StdRng::new().unwrap();
45 let mut rgradients = [Vec2 { x: 0.0, y: 0.0 }, ..256];
46 for x in rgradients.mut_iter() {
47 *x = random_gradient(&mut rng);
50 let mut permutations = [0i32, ..256];
51 for (i, x) in permutations.mut_iter().enumerate() {
54 rng.shuffle(permutations);
56 Noise2DContext { rgradients: rgradients, permutations: permutations }
59 fn get_gradient(&self, x: i32, y: i32) -> Vec2 {
60 let idx = self.permutations[(x & 255) as uint] +
61 self.permutations[(y & 255) as uint];
62 self.rgradients[(idx & 255) as uint]
65 fn get_gradients(&self, x: f32, y: f32) -> ([Vec2, ..4], [Vec2, ..4]) {
76 ([self.get_gradient(x0, y0), self.get_gradient(x1, y0),
77 self.get_gradient(x0, y1), self.get_gradient(x1, y1)],
78 [Vec2 { x: x0f, y: y0f }, Vec2 { x: x1f, y: y0f },
79 Vec2 { x: x0f, y: y1f }, Vec2 { x: x1f, y: y1f }])
82 fn get(&self, x: f32, y: f32) -> f32 {
83 let p = Vec2 {x: x, y: y};
84 let (gradients, origins) = self.get_gradients(x, y);
86 let v0 = gradient(origins[0], gradients[0], p);
87 let v1 = gradient(origins[1], gradients[1], p);
88 let v2 = gradient(origins[2], gradients[2], p);
89 let v3 = gradient(origins[3], gradients[3], p);
91 let fx = smooth(x - origins[0].x);
92 let vx0 = lerp(v0, v1, fx);
93 let vx1 = lerp(v2, v3, fx);
94 let fy = smooth(y - origins[0].y);
101 let symbols = [' ', '░', '▒', '▓', '█', '█'];
102 let mut pixels = [0f32, ..256*256];
103 let n2d = Noise2DContext::new();
105 for _ in range(0u, 100) {
106 for y in range(0u, 256) {
107 for x in range(0u, 256) {
108 let v = n2d.get(x as f32 * 0.1, y as f32 * 0.1);
109 pixels[y*256+x] = v * 0.5 + 0.5;
114 for y in range(0u, 256) {
115 for x in range(0u, 256) {
116 let idx = (pixels[y*256+x] / 0.2) as uint;
117 print!("{:c}", symbols[idx]);