init

src/main.rs

@@ -0,0 +1,65 @@
+use std::time::SystemTime;
+
+use image::{Rgb, RgbImage};
+
+const WIDTH: u32 = 4096;
+const HEIGHT: u32 = WIDTH / 2;
+
+const TOTAL_UNITS_WIDE: f64 = 4.0;
+
+const MAX_ITER: u32 = 512;
+const CX: f64 = -0.98;
+const CY: f64 = -0.277;
+
+const WIDTH_F: f64 = WIDTH as f64;
+const HEIGHT_F: f64 = HEIGHT as f64;
+const PIXELS_PER_UNIT: f64 = WIDTH_F / TOTAL_UNITS_WIDE;
+
+fn main() {
+	let start_time = SystemTime::now();
+
+	let mut img = RgbImage::new(WIDTH, HEIGHT);
+	for y in 0..HEIGHT {
+		for x in 0..WIDTH {
+			let pixel = fractal(x as f64, y as f64);
+			img.put_pixel(x, y, pixel);
+		}
+	}
+	println!(
+		"Generating took {} ms",
+		start_time.elapsed().unwrap().as_millis()
+	);
+	let start_time = SystemTime::now();
+	let filename = format!("julia_set_cx{:.3}_cy{:.3}.png", CX, CY);
+	img.save(filename).unwrap();
+	println!(
+		"Saving took {} ms",
+		start_time.elapsed().unwrap().as_millis()
+	);
+}
+
+fn fractal(x: f64, y: f64) -> Rgb<u8> {
+	let mut x = (x - WIDTH_F / 2.0) / PIXELS_PER_UNIT;
+	let mut y = (y - HEIGHT_F / 2.0) / PIXELS_PER_UNIT;
+
+	let mut iterations = 0;
+
+	while (x * x + y * y) < 4.0 {
+		(x, y) = (
+			x * x - y * y + CX, //
+			2.0 * x * y + CY,
+		);
+
+		iterations += 1;
+		if iterations == MAX_ITER {
+			return Rgb([0, 0, 0]);
+		}
+	}
+
+	let i = iterations.min(255) as u8;
+	Rgb([
+		i.saturating_mul(4),
+		i.saturating_mul(8),
+		i.saturating_mul(12),
+	])
+}