fix: refactor parts of mandelbrot.rs

src/lib.rs

@@ -1,2 +1,3 @@
+pub use crate::mandelbrot::Bounds;
 pub use crate::mandelbrot::Mandelbrot;
 mod mandelbrot;

src/main.rs

@@ -1,5 +1,5 @@
 use bevy::{prelude::*, render::texture::TextureFormat};
-use mandelbrot::Mandelbrot;
+use mandelbrot::{Bounds, Mandelbrot};
 use std::time::Instant;
 
 fn main() {
@@ -88,14 +88,16 @@ fn mandelbrot_render_system(
                     let z = scale.zoom;
                     let h = scale.horizontal;
                     let v = scale.vertical;
-                    let iters = scale.iterations;
+                    let limit = scale.iterations;
+
+                    let x = ((-2.5 * z) + h, (1.0 * z) + h);
+                    let y = ((-1.0 * z) - v, (1.0 * z) - v);
+                    let bounds = Bounds::new(x, y);
 
                     let start = Instant::now();
-                    texture.data.copy_from_slice(fractal.generate_scaled_image(
-                        ((-2.5 * z) + h, (1.0 * z) + h),
-                        ((-1.0 * z) - v, (1.0 * z) - v),
-                        iters,
-                    ));
+                    texture
+                        .data
+                        .copy_from_slice(fractal.scaled_image(bounds, limit));
                     let _diff = Instant::now() - start;
                 }
             }
@@ -109,7 +111,7 @@ fn startup(
     mut materials: ResMut<Assets<ColorMaterial>>,
 ) {
     let img_size = Vec2::new(Mandelbrot::width() as f32, Mandelbrot::height() as f32);
-    let img_buf = Mandelbrot::new().generate_image().to_vec();
+    let img_buf = Mandelbrot::new().image().to_vec();
 
     let texture_handle = textures.add(Texture::new(
         img_size,

src/mandelbrot.rs

@@ -1,7 +1,43 @@
 use num_complex::Complex;
 use rayon::prelude::*;
 
-const MAX_ITERATIONS: u16 = 512;
+pub struct Coordinate(usize, usize);
+
+impl Coordinate {
+    pub fn new(x: usize, y: usize) -> Self {
+        Self(x, y)
+    }
+
+    pub fn x(&self) -> usize {
+        self.0
+    }
+
+    pub fn y(&self) -> usize {
+        self.1
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct Bounds {
+    x: (f64, f64),
+    y: (f64, f64),
+}
+
+impl Bounds {
+    pub const fn new(x: (f64, f64), y: (f64, f64)) -> Self {
+        Self { x, y }
+    }
+    pub fn x(&self) -> (f64, f64) {
+        self.x
+    }
+
+    pub fn y(&self) -> (f64, f64) {
+        self.y
+    }
+}
+
+const DEFAULT_MAX_ITERATIONS: u32 = 64;
+const DEFAULT_BOUNDS: Bounds = Bounds::new((-2.5, 1.0), (-1.0, 1.0));
 
 #[derive(Debug, Clone)]
 pub struct Mandelbrot {
@@ -26,33 +62,32 @@ impl Mandelbrot {
         Self::IMG_HEIGHT
     }
 
-    pub fn generate_image(&mut self) -> &[u8] {
+    pub fn image(&mut self) -> &[u8] {
+        let max_iters = DEFAULT_MAX_ITERATIONS as f64;
+
         self.texture_buffer
             .par_chunks_mut(4)
             .enumerate()
             .for_each(|(i, buf)| {
-                let iters = Self::new_escape_time(i, (-2.5, 1.0), (-1.0, 1.0), 64);
-                let normalized_iters = iters / MAX_ITERATIONS as f64;
-                let h = 0.5 + (10.0 * normalized_iters);
-                buf.copy_from_slice(&Self::hsv_to_rgb(h, 0.6, 1.0));
+                let iters = Self::escape_time(i, DEFAULT_BOUNDS, DEFAULT_MAX_ITERATIONS);
+                let normalized_iters = iters / max_iters;
+
+                let h = normalized_iters * 350.0;
+                let v = if iters == max_iters { 0.0 } else { 1.0 };
+                buf.copy_from_slice(&Self::hsv_to_rgb(h, 1.0, v));
             });
 
         &self.texture_buffer
     }
 
-    pub fn generate_scaled_image(
-        &mut self,
-        x_bounds: (f64, f64),
-        y_bounds: (f64, f64),
-        max_iterations: u32,
-    ) -> &[u8] {
+    pub fn scaled_image(&mut self, bounds: Bounds, max_iterations: u32) -> &[u8] {
         self.texture_buffer
             .par_chunks_mut(4)
             .enumerate()
             .for_each(|(i, buf)| {
                 let max_iters = max_iterations as f64;
 
-                let iters = Self::new_escape_time(i, x_bounds, y_bounds, max_iterations);
+                let iters = Self::escape_time(i, bounds, max_iterations);
                 let normalized_iters = iters / max_iters;
 
                 let h = normalized_iters * 350.0;
@@ -63,17 +98,11 @@ impl Mandelbrot {
         &self.texture_buffer
     }
 
-    fn new_escape_time(
-        i: usize,
-        x_bounds: (f64, f64),
-        y_bounds: (f64, f64),
-        max_iterations: u32,
-    ) -> f64 {
-        let px = i % Self::IMG_WIDTH;
-        let py = i / Self::IMG_WIDTH;
-        let c = Self::coords_to_complex(px, py, x_bounds, y_bounds);
+    fn escape_time(i: usize, bounds: Bounds, max_iterations: u32) -> f64 {
+        let point = Coordinate::new(i % Self::IMG_WIDTH, i / Self::IMG_WIDTH);
+        let c = Self::coords_to_complex(point, bounds);
 
-        Self::new_calc_num_iters(c, max_iterations)
+        Self::count_iterations(c, max_iterations)
     }
 
     #[inline]
@@ -108,7 +137,7 @@ impl Mandelbrot {
         [r, g, b, a]
     }
 
-    fn new_calc_num_iters(c: Complex<f64>, max_iterations: u32) -> f64 {
+    fn count_iterations(c: Complex<f64>, max_iterations: u32) -> f64 {
         let mut z: Complex<f64> = Complex::new(0.0, 0.0);
         let mut num_iters: u32 = 0;
 
@@ -132,29 +161,26 @@ impl Mandelbrot {
         }
     }
 
-    fn coords_to_complex(
-        px: usize,
-        py: usize,
-        x_bounds: (f64, f64),
-        y_bounds: (f64, f64),
-    ) -> Complex<f64> {
+    fn coords_to_complex(point: Coordinate, bounds: Bounds) -> Complex<f64> {
         Complex::new(
-            Self::scale_width(px, x_bounds),
-            Self::scale_height(py, y_bounds),
+            Self::scale_width(point.x(), bounds.x()),
+            Self::scale_height(point.y(), bounds.y()),
         )
     }
 
-    fn scale_width(px: usize, x_bounds: (f64, f64)) -> f64 {
+    #[inline]
+    fn scale_width(x: usize, bounds: (f64, f64)) -> f64 {
         // const X_MIN: f64 = -2.5;
         // const X_MAX: f64 = 1.0;
 
-        x_bounds.0 + ((x_bounds.1 - x_bounds.0) * (px as f64 - 0.0)) / Self::IMG_WIDTH as f64 - 0.0
+        bounds.0 + ((bounds.1 - bounds.0) * (x as f64 - 0.0)) / Self::IMG_WIDTH as f64 - 0.0
     }
 
-    fn scale_height(py: usize, y_bounds: (f64, f64)) -> f64 {
+    #[inline]
+    fn scale_height(y: usize, bounds: (f64, f64)) -> f64 {
         // const Y_MIN: f64 = -1.0;
         // const Y_MAX: f64 = 1.0;
 
-        y_bounds.0 + ((y_bounds.1 - y_bounds.0) * (py as f64 - 0.0)) / Self::IMG_HEIGHT as f64 - 0.0
+        bounds.0 + ((bounds.1 - bounds.0) * (y as f64 - 0.0)) / Self::IMG_HEIGHT as f64 - 0.0
     }
 }