neftaly · June 13, 2025 22:53 · Jun 13, 2025
diff --git a/wheel.js b/wheel.js
@@ -0,0 +1,38 @@
+addEventListener("wheel", (event) => { })
+
+export const handleWheel = (event: PointerEvent, cameraConfig: Object) => (state) => {
+  // TODO: Add support for Safari touchpad gesture events
+  const {
+    altKey,
+    ctrlKey // `true` on trackpads when pinch-zooming (or ctrl key is pressed)
+  } = event
+
+  // Move camera (origin) when alt+wheeling
+  if (altKey) {
+    // Swap deltaX/deltaY if user is holding the ctrl key,
+    // so that 1-directional mouse scrollwheels can be used to move both forward/back and left/right
+    const [deltaX, deltaY] = ctrlKey
+      ? [event.deltaY, event.deltaX]
+      : [event.deltaX, event.deltaY]
+    const {
+      origin: [x, y, z]
+    } = state
+    const scaling = 50
+    const origin = [x - deltaX / scaling, y, z - deltaY / scaling]
+    return { origin }
+  }
+
+  // Rotate camera (coords)
+  const {
+    coords: [r, theta, phi]
+  } = state
+  // Swap deltaY/deltaZ if user is pinching (or ctrl+wheeling)
+  const [deltaY, deltaZ] = ctrlKey
+    ? [event.deltaZ, event.deltaY]
+    : [event.deltaY, event.deltaZ]
+  return [
+    r + deltaY / (500 / r), // Dolly faster as we move out further
+    theta - deltaZ / 100,
+    phi + event.deltaX / 200
+  ]
+}