Multitouch refactor

docs/multitouch.md

@@ -0,0 +1,213 @@
+# Decompiled MotionEvent Handler Analysis
+
+
+
+## Overview
+
+
+
+This function processes an Android `MotionEvent`, normalizes pointer coordinates to a 0–1 range, packs them into a custom event object, and forwards it to another component.
+
+
+
+---
+
+
+
+## What It Does
+
+
+
+1. Determines whether the event is a **press/move (1)** or **release (0)**:
+
+   - `ACTION_DOWN`, `ACTION_POINTER_DOWN`, `ACTION_MOVE` → state = 1  
+
+   - `ACTION_UP`, `ACTION_POINTER_UP` → state = 0  
+
+
+
+2. Iterates over active pointers (maximum of 5).
+
+
+
+3. For each pointer:
+
+   - Gets the pointer ID.
+
+   - If pointer ID ≥ 5 → abort and return `true`.
+
+   - For `ACTION_POINTER_DOWN` / `ACTION_POINTER_UP`, only processes the pointer at `getActionIndex()`.
+
+
+
+4. For each processed pointer:
+
+   - Gets raw X/Y coordinates.
+
+   - Subtracts offsets.
+
+   - Normalizes coordinates into `[0, 1]` using width/height bounds.
+
+   - Clamps values to `[0, 1]`.
+
+
+
+5. Stores per-pointer data into a custom container:
+
+   - Normalized X
+
+   - Normalized Y
+
+   - State (1 = down/move, 0 = up)
+
+   - Pointer ID
+
+
+
+6. Sends the packed structure to another component.
+
+
+
+7. Always returns `true`.
+
+
+
+---
+
+
+
+## Clean, Readable Version
+
+
+
+```java
+
+public static boolean handleMotionEvent(
+
+        MotionEvent event,
+
+        int offsetX,
+
+        int offsetY,
+
+        int width,
+
+        int height
+
+) {
+
+    TouchPacket packet = new TouchPacket();
+
+
+
+    int action = event.getActionMasked();
+
+
+
+    // Determine press state
+
+    int state;
+
+    if (action == MotionEvent.ACTION_DOWN ||
+
+        action == MotionEvent.ACTION_POINTER_DOWN ||
+
+        action == MotionEvent.ACTION_MOVE) {
+
+        state = 1; // pressed/moving
+
+    } else {
+
+        state = 0; // released
+
+    }
+
+
+
+    int pointerCount = Math.min(event.getPointerCount(), 5);
+
+
+
+    for (int i = 0; i < pointerCount; i++) {
+
+
+
+        int pointerId = event.getPointerId(i);
+
+
+
+        // Only support pointer IDs 0–4
+
+        if (pointerId >= 5) {
+
+            return true;
+
+        }
+
+
+
+        // If pointer down/up, only handle the changed pointer
+
+        if (action == MotionEvent.ACTION_POINTER_DOWN ||
+
+            action == MotionEvent.ACTION_POINTER_UP) {
+
+
+
+            int changedPointerId =
+
+                    event.getPointerId(event.getActionIndex());
+
+
+
+            if (pointerId != changedPointerId) {
+
+                continue;
+
+            }
+
+        }
+
+
+
+        float rawX = event.getX(i);
+
+        float rawY = event.getY(i);
+
+
+
+        int x = (int) rawX - offsetX;
+
+        int y = (int) rawY - offsetY;
+
+
+
+        float normX = normalize(x, width);
+
+        float normY = normalize(y, height);
+
+
+
+        packet.addPointer(normX, normY, state, pointerId);
+
+    }
+
+
+
+    TouchSender.send(packet);
+
+    return true;
+
+}
+
+
+
+private static float normalize(int value, int max) {
+
+    if (value <= 0) return 0f;
+
+    if (value >= max) return 1f;
+
+    return (float) value / (float) max;
+
+}