feat(mandelbrot): better coloring

boralg · Feb 17, 2025 · cf893a8 · cf893a8
1 parent a55d9c7
commit cf893a8
Showing 1 changed file with 26 additions and 19 deletions.
diff --git a/examples/src/mandelbrot/assets/shader.wgsl b/examples/src/mandelbrot/assets/shader.wgsl
@@ -24,35 +24,42 @@ fn vs_main(@location(0) position: vec3<f32>, @location(1) uv: vec2<f32>) -> Vert
 @fragment
 fn fs_main(@location(0) fragUV: vec2<f32>) -> @location(0) vec4<f32> {
     let max_iter: u32 = 100u;
-
-    // Calculate the coordinates in the complex plane
-    let centered_uv = (fragUV * 2.0 - vec2<f32>(1.0, 1.0)) * vec2<f32>(uniforms.aspect_ratio, 1.0); // Convert [0,1] range to [-1,1] and adjust for aspect ratio
 
-    // Adjust coordinates based on translation and scale, without affecting rotation
-    let c = uniforms.translation + vec2<f32>(
-        centered_uv.x * uniforms.scale,
-        centered_uv.y * uniforms.scale
-    );
+    let centered_uv = (fragUV * 2.0 - vec2<f32>(1.0, 1.0)) * vec2<f32>(uniforms.aspect_ratio, 1.0);
+    let c = uniforms.translation + centered_uv * uniforms.scale;
 
-    var z: vec2<f32> = vec2<f32>(0.0, 0.0);
+    var z = vec2<f32>(0.0, 0.0);
     var iter: u32 = 0u;
 
-    // Iterate to determine if the point is in the Mandelbrot set
-    for (var i: u32 = 0u; i < max_iter; i = i + 1u) {
-        if (dot(z, z) > 4.0) {
-            break;
-        }
+    for (var i: u32 = 0u; i < max_iter; i++) {
+        if (dot(z, z) > 4.0) { break; }
         z = vec2<f32>(
             z.x * z.x - z.y * z.y + c.x,
             2.0 * z.x * z.y + c.y
         );
-        iter = iter + 1u;
+        iter++;
     }
 
     if (iter == max_iter) {
-        return vec4<f32>(0.0, 0.0, 0.0, 1.0);  // Inside the Mandelbrot set
+        return vec4<f32>(0.0, 0.0, 0.0, 1.0);
     } else {
-        let t: f32 = f32(iter) / f32(max_iter);
-        return vec4<f32>(t * 0.15, t * 0.35, t * 0.25, 1.0); // Gradient color for points outside
+        let modulus_squared = dot(z, z);
+        let log_zn = 0.5 * log2(modulus_squared);
+        let nu = log2(log_zn);
+        let smooth_iter = f32(iter) + 1.0 - nu;
+        let t = smooth_iter / f32(max_iter);
+
+        let speed = 2.0;
+        let brightness = 0.7;
+        let r = brightness * sin(t * speed * 6.2831);
+        let g = brightness * sin(t * speed * 6.2831 + 2.094);
+        let b = brightness * sin(t * speed * 6.2831 + 4.188);
+
+        return vec4<f32>(
+            0.5 + r * 0.5,
+            0.5 + g * 0.5,
+            0.5 + b * 0.5,
+            1.0
+        );
     }
-}
+}