mandelbrot/
mandelbrot.rs

1/// Slightly modify the example on crate `simd` to make it work on stable channel 
2/// Reference link : https://github.com/rust-lang-nursery/simd
3
4use std::io::prelude::*;
5
6extern crate ssimd;
7use ssimd::{u32x4, f32x4};
8
9#[inline(never)]
10fn mandelbrot_naive(c_x: f32, c_y: f32, max_iter: u32) -> u32 {
11    let mut x = c_x;
12    let mut y = c_y;
13    let mut count = 0;
14    while count < max_iter {
15        let xy = x * y;
16        let xx = x * x;
17        let yy = y * y;
18        let sum = xx + yy;
19        if sum > 4.0 {
20            break
21        }
22        count += 1;
23        x = xx - yy + c_x;
24        y = xy * 2.0 + c_y;
25    }
26    count
27}
28
29#[inline(never)]
30fn mandelbrot_vector(c_x: f32x4, c_y: f32x4, max_iter: u32) -> u32x4 {
31    let mut x = c_x;
32    let mut y = c_y;
33
34    let mut count = u32x4::splat(0);
35    for _ in 0..max_iter as usize {
36        let xy = x * y;
37        let xx = x * x;
38        let yy = y * y;
39        let sum = xx + yy;
40        let mask = sum.lt(f32x4::splat(4.0));
41
42        if !mask.any() { break }
43        count = count + mask.to_u().select(u32x4::splat(1),
44                                           u32x4::splat(0));
45
46        x = xx - yy + c_x;
47        y = xy + xy + c_y;
48    }
49    count
50}
51
52const COLOURS: &'static [(f32, f32, f32)] = &[(0.0, 7.0, 100.0),
53                                              (32.0, 107.0, 203.0),
54                                              (237.0, 255.0, 255.0),
55                                              (255.0, 170.0, 0.0),
56                                              (0.0, 2.0, 0.0)];
57const SCALE: f32 = 12.0;
58const LIMIT: u32 = 100;
59
60#[inline(never)]
61fn output_one(buf: &mut [u8], val: u32) {
62    let (r, g, b);
63    if val == LIMIT {
64        r = 0;
65        g = 0;
66        b = 0;
67    } else {
68        let val = (val as f32 % SCALE) * (COLOURS.len() as f32) / SCALE;
69        let left = val as usize % COLOURS.len();
70        let right = (left + 1) % COLOURS.len();
71
72        let p = val - left as f32;
73        let (r1, g1, b1) = COLOURS[left];
74        let (r2, g2, b2) = COLOURS[right];
75        r = (r1 + (r2 - r1) * p) as u8;
76        g = (g1 + (g2 - g1) * p) as u8;
77        b = (b1 + (b2 - b1) * p) as u8;
78    }
79    buf[0] = r;
80    buf[1] = g;
81    buf[2] = b;
82}
83
84fn main() {
85    let mut args = std::env::args();
86    args.next();
87    let width = args.next().unwrap().parse().unwrap();
88    let height = args.next().unwrap().parse().unwrap();
89
90    let left = -2.2;
91    let right = left + 3.0;
92    let top = 1.0;
93    let bottom = top - 2.0;
94
95    let width_step: f32 = (right - left) / width as f32;
96    let height_step: f32 = (bottom - top) / height as f32;
97
98    let adjust = f32x4::splat(width_step) * f32x4::new(0., 1., 2., 3.);
99
100    println!("P6 {} {} 255", width, height);
101    let mut line = vec![0; width * 3];
102
103    if args.next().is_none() {
104        for i in 0..height {
105            let y = f32x4::splat(top + height_step * i as f32);
106            for _j in 0..width/4 {
107                let j = 4*_j;
108                let x = f32x4::splat(left + width_step * j as f32) + adjust;
109                let ret = mandelbrot_vector(x, y, LIMIT);
110                //test::black_box(ret);
111                for k in 0..4 { let val = ret.extract(k as u32); output_one(&mut line[3*(j + k)..3*(j + k + 1)], val); }
112            }
113            ::std::io::stdout().write(&line).unwrap();
114        }
115    } else {
116        for i in 0..height {
117            let y = top + height_step * i as f32;
118            for j in 0..width {
119                let x = left + width_step * j as f32;
120                let val = mandelbrot_naive(x, y, LIMIT);
121                //test::black_box(val);
122                output_one(&mut line[3*j..3*(j + 1)], val);
123            }
124            ::std::io::stdout().write(&line).unwrap();
125        }
126    }
127}
mandelbrot/mandelbrot.rs

mandelbrot/
mandelbrot.rs
