feat(babylon_setup.js): v to change view

Co-authored-by: Copilot <copilot@github.com>

src/babylon_setup.js

@@ -38,15 +38,63 @@ camera.applyGravity = true;
 camera.ellipsoid = new BABYLON.Vector3(0.35, 0.9, 0.35);
 camera.attachControl(canvas, true);
 
+const overviewCamera = new BABYLON.ArcRotateCamera(
+    "overviewCam",
+    -Math.PI / 2,
+    Math.PI / 3.2,
+    40,
+    new BABYLON.Vector3(0, 0, 0),
+    scene,
+);
+overviewCamera.lowerBetaLimit = 0.2;
+overviewCamera.upperBetaLimit = Math.PI / 2.05;
+overviewCamera.lowerRadiusLimit = 8;
+overviewCamera.inertia = 0.7;
+
+let cameraMode = "fp";
+scene.activeCamera = camera;
+
 scene.gravity = new BABYLON.Vector3(0, -0.2, 0);
 scene.collisionsEnabled = true;
 
 canvas.addEventListener("click", () => {
-    if (document.pointerLockElement !== canvas) {
+    if (cameraMode === "fp" && document.pointerLockElement !== canvas) {
         canvas.requestPointerLock();
     }
 });
 
+function updateOverviewCameraForMaze(w, h) {
+    const mazeSpan = Math.max(w, h) * cellSize;
+    overviewCamera.radius = Math.max(mazeSpan * 1.05, 16);
+    overviewCamera.target = new BABYLON.Vector3(0, 0, 0);
+}
+
+function switchCameraMode() {
+    if (cameraMode === "fp") {
+        if (document.pointerLockElement === canvas && document.exitPointerLock) {
+            document.exitPointerLock();
+        }
+        camera.detachControl(canvas);
+        overviewCamera.attachControl(canvas, true);
+        scene.activeCamera = overviewCamera;
+        cameraMode = "overview";
+        sharedState.runtime.message = "Overview camera (press V to return to first-person).";
+        return;
+    }
+
+    overviewCamera.detachControl(canvas);
+    camera.attachControl(canvas, true);
+    scene.activeCamera = camera;
+    cameraMode = "fp";
+    sharedState.runtime.message = "First-person camera (W/A/S/D + mouse).";
+}
+
+window.addEventListener("keydown", (event) => {
+    if (event.code === "KeyV") {
+        switchCameraMode();
+    }
+});
+
 new BABYLON.HemisphericLight("light", new BABYLON.Vector3(0, 1, 0), scene);
 
 // Placeholder sphere
@@ -320,6 +368,7 @@ function generateLevel() {
     const w = Math.max(9, cfg.mazeWidth);
     const h = Math.max(9, cfg.mazeHeight);
     const grid = generateMazeGrid(w, h, seed + cfg.level);
+    updateOverviewCameraForMaze(w, h);
     const dead = findDeadEnds(grid);
     buildLevelFromGrid(grid);
     placeChestsOnDeadEnds(grid, dead, cfg.minChestDeadEnds, seed + cfg.level);