feat: add more colours to mandelbrot visualization

src/mandelbrot.rs

@@ -1,7 +1,7 @@
 use num_complex::Complex;
 use rayon::prelude::*;
 
-const MAX_ITERATIONS: u16 = 1024;
+const MAX_ITERATIONS: u16 = 512;
 
 #[derive(Debug, Clone)]
 pub struct Mandelbrot {
@@ -9,9 +9,15 @@ pub struct Mandelbrot {
 }
 
 enum Colour {
+    Purple,
+    Violet,
+    Blue,
+    Green,
+    Yellow,
+    Orange,
+    Red,
     White,
     Black,
-    Gray,
 }
 
 impl Mandelbrot {
@@ -33,35 +39,13 @@ impl Mandelbrot {
     }
 
     pub fn generate_image(&mut self) -> Vec<u8> {
-        // Create the image
+        self.escape_time((-2.5, 1.0), (-1.0, 1.0));
-        // Pixel Format can be Rgba8UnormSrgb
-        self.escape_time();
 
         let mut texture_buffer = vec![0; (Self::IMG_WIDTH * Self::IMG_HEIGHT) * 4];
-
         for i in 0..texture_buffer.len() {
             if i % 4 == 0 {
                 let iter_i = i / 4;
-                match Self::find_colour(self.iterations[iter_i]) {
+                self.assign_colour(i, iter_i, &mut texture_buffer);
-                    Colour::White => {
-                        texture_buffer[i] = 0x00;
-                        texture_buffer[i + 1] = 0x00;
-                        texture_buffer[i + 2] = 0x00;
-                        texture_buffer[i + 3] = 0xFF;
-                    }
-                    Colour::Black => {
-                        texture_buffer[i] = 0xFF;
-                        texture_buffer[i + 1] = 0xFF;
-                        texture_buffer[i + 2] = 0xFF;
-                        texture_buffer[i + 3] = 0xFF;
-                    }
-                    Colour::Gray => {
-                        texture_buffer[i] = 0xAA;
-                        texture_buffer[i + 1] = 0xAA;
-                        texture_buffer[i + 2] = 0xAA;
-                        texture_buffer[i + 3] = 0xFF;
-                    }
-                }
             }
         }
 
@@ -70,6 +54,20 @@ impl Mandelbrot {
 
     pub fn generate_scaled_image(&mut self, x_bounds: (f64, f64), y_bounds: (f64, f64)) -> Vec<u8> {
         let mut texture_buffer = vec![0; (Self::IMG_WIDTH * Self::IMG_HEIGHT) * 4];
+
+        self.escape_time(x_bounds, y_bounds);
+
+        for i in 0..texture_buffer.len() {
+            if i % 4 == 0 {
+                let iter_i = i / 4;
+                self.assign_colour(i, iter_i, &mut texture_buffer);
+            }
+        }
+
+        texture_buffer
+    }
+
+    fn escape_time(&mut self, x_bounds: (f64, f64), y_bounds: (f64, f64)) {
         self.iterations
             .par_iter_mut()
             .enumerate()
@@ -79,60 +77,83 @@ impl Mandelbrot {
 
                 let c = Self::coords_to_complex(px, py, x_bounds, y_bounds);
 
-                *value = Self::calc_num_iterations(c);
-            });
-
-        for i in 0..texture_buffer.len() {
-            if i % 4 == 0 {
-                let iter_i = i / 4;
-                match Self::find_colour(self.iterations[iter_i]) {
-                    Colour::White => {
-                        texture_buffer[i] = 0x00;
-                        texture_buffer[i + 1] = 0x00;
-                        texture_buffer[i + 2] = 0x00;
-                        texture_buffer[i + 3] = 0xFF;
-                    }
-                    Colour::Black => {
-                        texture_buffer[i] = 0xFF;
-                        texture_buffer[i + 1] = 0xFF;
-                        texture_buffer[i + 2] = 0xFF;
-                        texture_buffer[i + 3] = 0xFF;
-                    }
-                    Colour::Gray => {
-                        texture_buffer[i] = 0xAA;
-                        texture_buffer[i + 1] = 0xAA;
-                        texture_buffer[i + 2] = 0xAA;
-                        texture_buffer[i + 3] = 0xFF;
-                    }
-                }
-            }
-        }
-
-        texture_buffer
-    }
-
-    fn escape_time(&mut self) {
-        self.iterations
-            .par_iter_mut()
-            .enumerate()
-            .for_each(|(i, value)| {
-                let px = i % Self::IMG_WIDTH;
-                let py = i / Self::IMG_WIDTH;
-
-                let c = Self::coords_to_complex(px, py, (-2.5, 1.0), (-1.0, 1.0));
-
                 *value = Self::calc_num_iterations(c);
             });
     }
 
     fn find_colour(iteration: u16) -> Colour {
-        match iteration {
+        if iteration == 1 {
-            MAX_ITERATIONS => Colour::Black,
+            return Colour::Black;
-            other => match other % 2 {
+        }
-                0 => Colour::White,
+
-                1 => Colour::Gray,
+        match iteration % 7 {
-                _ => unreachable!(),
+            0 => Colour::Purple,
-            },
+            1 => Colour::Violet,
+            2 => Colour::Blue,
+            3 => Colour::Green,
+            4 => Colour::Yellow,
+            5 => Colour::Orange,
+            6 => Colour::Red,
+            _ => unreachable!(),
+        }
+    }
+
+    fn assign_colour(&self, i: usize, iter_i: usize, texture_buffer: &mut [u8]) {
+        match Self::find_colour(self.iterations[iter_i]) {
+            Colour::White => {
+                texture_buffer[i] = 0xFF;
+                texture_buffer[i + 1] = 0xFF;
+                texture_buffer[i + 2] = 0xFF;
+                texture_buffer[i + 3] = 0xFF;
+            }
+            Colour::Black => {
+                texture_buffer[i] = 0x00;
+                texture_buffer[i + 1] = 0x00;
+                texture_buffer[i + 2] = 0x00;
+                texture_buffer[i + 3] = 0xFF;
+            }
+            Colour::Purple => {
+                texture_buffer[i] = 0x94;
+                texture_buffer[i + 1] = 0x00;
+                texture_buffer[i + 2] = 0xD3;
+                texture_buffer[i + 3] = 0xFF;
+            }
+            Colour::Violet => {
+                texture_buffer[i] = 0x4B;
+                texture_buffer[i + 1] = 0x00;
+                texture_buffer[i + 2] = 0x82;
+                texture_buffer[i + 3] = 0xFF;
+            }
+            Colour::Blue => {
+                texture_buffer[i] = 0x00;
+                texture_buffer[i + 1] = 0x00;
+                texture_buffer[i + 2] = 0xFF;
+                texture_buffer[i + 3] = 0xFF;
+            }
+            Colour::Green => {
+                texture_buffer[i] = 0x00;
+                texture_buffer[i + 1] = 0xFF;
+                texture_buffer[i + 2] = 0x00;
+                texture_buffer[i + 3] = 0xFF;
+            }
+            Colour::Yellow => {
+                texture_buffer[i] = 0xFF;
+                texture_buffer[i + 1] = 0xFF;
+                texture_buffer[i + 2] = 0x00;
+                texture_buffer[i + 3] = 0xFF;
+            }
+            Colour::Orange => {
+                texture_buffer[i] = 0xFF;
+                texture_buffer[i + 1] = 0x7F;
+                texture_buffer[i + 2] = 0x00;
+                texture_buffer[i + 3] = 0xFF;
+            }
+            Colour::Red => {
+                texture_buffer[i] = 0xFF;
+                texture_buffer[i + 1] = 0x00;
+                texture_buffer[i + 2] = 0x00;
+                texture_buffer[i + 3] = 0xFF;
+            }
         }
     }
 
@@ -149,7 +170,7 @@ impl Mandelbrot {
             z = (z * z) + c;
         }
 
-        num_iterations
+        num_iterations + 1 // account for off by one error
     }
 
     fn coords_to_complex(