Update world.js

world.js

@@ -1,4 +1,41 @@
-export function updateWorld(Psi, sigma){
-  // fractal / field evolution placeholder
-  // hook WebGL / Mandelbulb here
+let field;
+let W = 256, H = 256;
+
+export function initWorld() {
+  field = new Float32Array(W * H);
+  for (let i = 0; i < field.length; i++) {
+    field[i] = Math.random();
+  }
+}
+
+export function updateWorld(Psi, sigma) {
+  const next = new Float32Array(field.length);
+
+  for (let y = 1; y < H - 1; y++) {
+    for (let x = 1; x < W - 1; x++) {
+      const i = y * W + x;
+      const lap =
+        field[i - 1] +
+        field[i + 1] +
+        field[i - W] +
+        field[i + W] -
+        4 * field[i];
+
+      next[i] = field[i] + sigma * lap + Psi * 0.01;
+    }
+  }
+  field = next;
+}
+
+export function renderWorld(ctx, canvas) {
+  const img = ctx.createImageData(W, H);
+  for (let i = 0; i < field.length; i++) {
+    const v = Math.max(0, Math.min(1, field[i]));
+    img.data[i * 4 + 0] = v * 255;
+    img.data[i * 4 + 1] = v * 255;
+    img.data[i * 4 + 2] = 255;
+    img.data[i * 4 + 3] = 255;
+  }
+  ctx.putImageData(img, 0, 0);
+  ctx.drawImage(canvas, 0, 0, canvas.width, canvas.height);
 }