cool stuff

shaders/mandelbrot.frag

@@ -1,31 +1,56 @@
 #version 100
-precision mediump float;
+precision highp float;
+
 uniform float u_time;
 uniform vec2 u_resolution;
+uniform float u_zoom;
+uniform vec2 u_center;
 
 void main() {
-    vec2 uv = (gl_FragCoord.xy * 2.0 - u_resolution.xy) / u_resolution.y;
+    // Current pixel coordinate in 0..1
+    vec2 st = gl_FragCoord.xy / u_resolution.xy;
+    st.x *= u_resolution.x / u_resolution.y; // Aspect ratio correction
     
-    // Auto zoom
-    float zoom = 1.0 + sin(u_time * 0.1) * 0.5;
-    zoom = pow(zoom, 4.0);
-    vec2 c = uv / zoom - vec2(0.74364388703, 0.13182590421); // Zoom into a specific interesting point
+    // Map to Mandelbrot space using Zoom and Center
+    // Default (Zoom 1): -2.5 to 1.5 X, -1.5 to 1.5 Y approx?
+    // Let's say center is 0,0. Range -2..2.
+    // st is 0..AspectRatio (approx 0..1.7)
     
+    // Center the coords:
+    vec2 c_uv = (gl_FragCoord.xy - u_resolution.xy * 0.5) / u_resolution.y;
+    
+    // Apply Zoom and Pan
+    vec2 c = (c_uv / u_zoom) + u_center;
+
+    // Mandelbrot iteration
     vec2 z = vec2(0.0);
     float iter = 0.0;
-    float max_iter = 100.0;
+    float max_iter = 100.0 + log(u_zoom) * 20.0; // Increase details with zoom
     
-    for (float i = 0.0; i < 100.0; i++) {
-        z = vec2(z.x * z.x - z.y * z.y, 2.0 * z.x * z.y) + c;
-        if (length(z) > 4.0) break;
-        iter += 1.0;
+    for (float i = 0.0; i < 500.0; i++) {
+        if (i > max_iter) break;
+        // Z = Z^2 + C
+        float x = (z.x * z.x - z.y * z.y) + c.x;
+        float y = (z.y * z.x + z.x * z.y) + c.y;
+        
+        if ((x * x + y * y) > 4.0) {
+            iter = i;
+            break;
+        }
+        z.x = x;
+        z.y = y;
     }
     
-    float f = iter / max_iter;
-    vec3 col = vec3(f);
-    col = 0.5 + 0.5 * cos(3.0 + f * 10.0 + vec3(0.0, 0.6, 1.0));
-    
-    if (iter >= 99.0) col = vec3(0.0);
-    
-    gl_FragColor = vec4(col, 1.0);
+    // Coloring
+    float t = iter / max_iter;
+    if (iter == 0.0) {
+        gl_FragColor = vec4(0.0, 0.0, 0.0, 1.0);
+    } else {
+        gl_FragColor = vec4(
+            sqrt(t),
+            t * t,
+            sin(t * 3.1415),
+            1.0
+        );
+    }
 }