rust/src/test/bench/noise.rs

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// Perlin noise benchmark from https://gist.github.com/1170424
use std::float;
use std::int;
use std::rand::{Rng, RngUtil};
use std::rand;
struct Vec2 {
x: f32,
y: f32,
}
#[inline(always)]
fn lerp(a: f32, b: f32, v: f32) -> f32 { a * (1.0 - v) + b * v }
#[inline(always)]
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 {
let v = 2.0 * float::consts::pi * r.gen();
Vec2 {
x: v.cos() as f32,
y: v.sin() as f32,
}
}
fn gradient(orig: Vec2, grad: Vec2, p: Vec2) -> f32 {
let sp = Vec2 {x: p.x - orig.x, y: p.y - orig.y};
grad.x * sp.x + grad.y + sp.y
}
struct Noise2DContext {
rgradients: [Vec2, ..256],
permutations: [int, ..256],
}
impl Noise2DContext {
pub fn new() -> Noise2DContext {
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let mut r = rand::rng();
let mut rgradients = [ Vec2 { x: 0.0, y: 0.0 }, ..256 ];
foreach i in range(0, 256) {
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rgradients[i] = random_gradient(&mut r);
}
let mut permutations = [ 0, ..256 ];
foreach i in range(0, 256) {
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permutations[i] = i;
}
r.shuffle_mut(permutations);
Noise2DContext {
rgradients: rgradients,
permutations: permutations,
}
}
#[inline(always)]
pub fn get_gradient(&self, x: int, y: int) -> Vec2 {
let idx = self.permutations[x & 255] + self.permutations[y & 255];
self.rgradients[idx & 255]
}
#[inline]
pub fn get_gradients(&self,
gradients: &mut [Vec2, ..4],
origins: &mut [Vec2, ..4],
x: f32,
y: f32) {
let x0f = x.floor();
let y0f = y.floor();
let x0 = x0f as int;
let y0 = y0f as int;
let x1 = x0 + 1;
let y1 = y0 + 1;
gradients[0] = self.get_gradient(x0, y0);
gradients[1] = self.get_gradient(x1, y0);
gradients[2] = self.get_gradient(x0, y1);
gradients[3] = self.get_gradient(x1, y1);
origins[0] = Vec2 {x: x0f + 0.0, y: y0f + 0.0};
origins[1] = Vec2 {x: x0f + 1.0, y: y0f + 0.0};
origins[2] = Vec2 {x: x0f + 0.0, y: y0f + 1.0};
origins[3] = Vec2 {x: x0f + 1.0, y: y0f + 1.0};
}
#[inline]
pub fn get(&self, x: f32, y: f32) -> f32 {
let p = Vec2 {x: x, y: y};
let mut gradients = [ Vec2 { x: 0.0, y: 0.0 }, ..4 ];
let mut origins = [ Vec2 { x: 0.0, y: 0.0 }, ..4 ];
self.get_gradients(&mut gradients, &mut origins, 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 = [0f32, ..256*256];
let n2d = ~Noise2DContext::new();
do 100.times {
foreach y in range(0, 256) {
foreach x in range(0, 256) {
let v = n2d.get(
x as f32 * 0.1f32,
y as f32 * 0.1f32
) * 0.5f32 + 0.5f32;
pixels[y*256+x] = v;
};
};
};
foreach y in range(0, 256) {
foreach x in range(0, 256) {
print((symbols[pixels[y*256+x] / 0.2f32) as int]);
}
println("");
}
}