111 lines
3.3 KiB
Rust
111 lines
3.3 KiB
Rust
// Perlin noise benchmark from https://gist.github.com/1170424
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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: rand::Rng) -> Vec2 {
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let v = r.gen_float() * float::consts::pi * 2.0;
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Vec2{
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x: float::cos(v) as f32,
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y: float::sin(v) as f32,
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}
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}
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fn gradient(orig: Vec2, grad: Vec2, p: Vec2) -> f32 {
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let sp = Vec2{x: p.x - orig.x, y: p.y - orig.y};
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grad.x * sp.x + grad.y + sp.y
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}
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struct Noise2DContext {
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rgradients: [Vec2 * 256],
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permutations: [int * 256],
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}
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fn Noise2DContext() -> ~Noise2DContext {
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let r = rand::Rng();
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let mut rgradients = [ Vec2 { x: 0.0, y: 0.0 }, ..256 ];
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for int::range(0, 256) |i| { rgradients[i] = random_gradient(r); }
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let mut permutations = [ 0, ..256 ];
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for int::range(0, 256) |i| { permutations[i] = i; }
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r.shuffle_mut(permutations);
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~Noise2DContext{
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rgradients: rgradients,
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permutations: permutations,
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}
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}
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impl Noise2DContext {
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#[inline(always)]
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fn get_gradient(&self, x: int, y: int) -> 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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#[inline(always)]
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fn get_gradients(&self, gradients: &mut [Vec2 * 4], origins: &mut [Vec2 * 4], x: f32, y: f32) {
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let x0f = f32::floor(x);
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let y0f = f32::floor(y);
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let x0 = x0f as int;
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let y0 = y0f as int;
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let x1 = x0 + 1;
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let y1 = y0 + 1;
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gradients[0] = self.get_gradient(x0, y0);
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gradients[1] = self.get_gradient(x1, y0);
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gradients[2] = self.get_gradient(x0, y1);
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gradients[3] = self.get_gradient(x1, y1);
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origins[0] = Vec2{x: x0f + 0.0, y: y0f + 0.0};
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origins[1] = Vec2{x: x0f + 1.0, y: y0f + 0.0};
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origins[2] = Vec2{x: x0f + 0.0, y: y0f + 1.0};
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origins[3] = Vec2{x: x0f + 1.0, y: y0f + 1.0};
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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 mut gradients = [ Vec2 { x: 0.0, y: 0.0 }, ..4 ];
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let mut origins = [ Vec2 { x: 0.0, y: 0.0 }, ..4 ];
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self.get_gradients(&mut gradients, &mut origins, 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 = vec::from_elem(256*256, 0f32);
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let n2d = Noise2DContext();
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for int::range(0, 100) |_| {
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for int::range(0, 256) |y| {
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for int::range(0, 256) |x| {
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let v = n2d.get(
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x as f32 * 0.1f32,
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y as f32 * 0.1f32
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) * 0.5f32 + 0.5f32;
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pixels[y*256+x] = v;
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};
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};
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};
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/*for int::range(0, 256) |y| {
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for int::range(0, 256) |x| {
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io::print(symbols[pixels[y*256+x] / 0.2f32 as int]);
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}
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io::println("");
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}*/
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}
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