[add] mandlebrot set

Author: FreeCX

src/56-mandlebrot-set.rs

@@ -0,0 +1,77 @@
+extern crate sdl2;
+
+use sdl2::pixels::PixelFormatEnum;
+use sdl2::pixels::Color;
+use sdl2::event::Event;
+use sdl2::keyboard::Keycode;
+use sdl2::render::{Renderer, Texture};
+use sdl2::rect::Rect;
+use std::f32;
+
+const W_WIDTH: u32 = 640;
+const W_HEIGHT: u32 = 480;
+const X_MIN: f32 = -2.5;
+const X_MAX: f32 = 1.0;
+const Y_MIN: f32 = -1.0;
+const Y_MAX: f32 = 1.0;
+const MAX_ITERATION: u8 = 255;
+
+fn delta(min: f32, max: f32, width: f32) -> f32 {
+ (min.abs() + max.abs()) / width
+}
+
+fn render<'a>(renderer: &'a mut Renderer, texture: &Texture) {
+ renderer.set_draw_color(Color::RGB(0, 0, 0));
+ renderer.clear();
+ renderer.copy(texture, None, Some(Rect::new(0, 0, W_WIDTH, W_HEIGHT))).unwrap();
+ renderer.present();
+}
+
+fn main() {
+ let sdl_contex = sdl2::init().unwrap();
+ let video_subsystem = sdl_contex.video().unwrap();
+ let window = video_subsystem.window("mandlebrot set", W_WIDTH, W_HEIGHT)
+ .position_centered()
+ .build()
+ .unwrap();
+ let mut renderer = window.renderer()
+ .present_vsync()
+ .build()
+ .unwrap();
+ let dx = delta(X_MIN, X_MAX, W_WIDTH as f32);
+ let dy = delta(Y_MIN, Y_MAX, W_HEIGHT as f32);
+ let mut texture = renderer.create_texture_streaming(PixelFormatEnum::RGB24, W_WIDTH, W_HEIGHT).unwrap();
+ texture.with_lock(None, |buffer: &mut [u8], pitch: usize| {
+ for px in 0..W_WIDTH {
+ for py in 0..W_HEIGHT {
+ let x0 = (px as f32) * dx + X_MIN;
+ let y0 = (py as f32) * dy + Y_MIN;
+ let mut x: f32 = 0.0;
+ let mut y: f32 = 0.0;
+ let mut iteration = 0;
+ while x.powi(2) + y.powi(2) < 4.0 && iteration < MAX_ITERATION {
+ let xtemp = x.powi(2) - y.powi(2) + x0;
+ y = 2.0 * x * y + y0;
+ x = xtemp;
+ iteration += 1;
+ }
+ let offset = (py as usize) * pitch + (px as usize) * 3;
+ buffer[offset + 0] = 0;
+ buffer[offset + 1] = 0;
+ buffer[offset + 2] = iteration;
+ }
+ }
+ }).unwrap();
+ let mut event_pump = sdl_contex.event_pump().unwrap();
+ 'running: loop {
+ for event in event_pump.poll_iter() {
+ match event {
+ Event::Quit {..} | Event::KeyDown { keycode: Some(Keycode::Escape), ..} => {
+ break 'running;
+ }
+ _ => ()
+ }
+ }
+ render(&mut renderer, &texture);
+ }
+}