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