```javascript
// SquirrelVision 3D Playground - Main Game Script

class SquirrelVisionPlayground {
    constructor() {
        this.scene = null;
        this.camera = null;
        this.renderer = null;
        this.controls = null;
        this.objects = [];
        this.isPlaying = false;
        this.moveForward = false;
        this.moveBackward = false;
        this.moveLeft = false;
        this.moveRight = false;
        this.canJump = false;
        this.prevTime = performance.now();
        this.velocity = new THREE.Vector3();
        this.direction = new THREE.Vector3();
        this.interactiveObjects = [];
        
        this.init();
    }

    async init() {
        // Update loading progress
        this.updateLoadingProgress(10, 'Creating 3D scene...');
        
        // Create scene
        this.scene = new THREE.Scene();
        this.scene.background = new THREE.Color(0x87CEEB); // Sky blue
        
        // Create camera
        this.camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000);
        this.camera.position.set(0, 1.6, 0);
        
        // Create renderer
        this.renderer = new THREE.WebGLRenderer({ antialias: true });
        this.renderer.setSize(window.innerWidth, window.innerHeight);
        this.renderer.shadowMap.enabled = true;
        this.renderer.shadowMap.type = THREE.PCFSoftShadowMap;
        
        // Add renderer to DOM
        document.getElementById('gameContainer').appendChild(this.renderer.domElement);
        
        this.updateLoadingProgress(30, 'Setting up lighting...');
        await this.setupLighting();
        
        this.updateLoadingProgress(50, 'Creating world geometry...');
        await this.createWorld();
        
        this.updateLoadingProgress(70, 'Adding interactive objects...');
        await this.addInteractiveObjects();
        
        this.updateLoadingProgress(90, 'Setting up controls...');
        this.setupControls();
        
        this.updateLoadingProgress(100, 'Ready!');
        
        // Show start screen after a brief delay
        setTimeout(() => {
            document.getElementById('loadingScreen').style.display = 'none';
            document.getElementById('startScreen').style.display = 'flex';
        }, 500);
        
        // Start animation loop
        this.animate();
        
        // Handle window resize
        window.addEventListener('resize', () => this.onWindowResize());
    }

    updateLoadingProgress(percent, text) {
        document.getElementById('progressBar').style.width = percent + '%';
        document.getElementById('loadingText').textContent = text;
    }

    async setupLighting() {
        // Ambient light
        const ambientLight = new THREE.AmbientLight(0x404040, 0.6);
        this.scene.add(ambientLight);
        
        // Directional light (sun)
        const directionalLight = new THREE.DirectionalLight(0xffffff, 1);
        directionalLight.position.set(50, 50, 50);
        directionalLight.castShadow = true;
        directionalLight.shadow.mapSize.width = 2048;
        directionalLight.shadow.mapSize.height = 2048;
        directionalLight.shadow.camera.near = 0.5;
        directionalLight.shadow.camera.far = 500;
        directionalLight.shadow.camera.left = -100;
        directionalLight.shadow.camera.right = 100;
        directionalLight.shadow.camera.top = 100;
        directionalLight.shadow.camera.bottom = -100;
        this.scene.add(directionalLight);
        
        // Hemisphere light for more natural outdoor lighting
        const hemisphereLight = new THREE.HemisphereLight(0x87CEEB, 0x8B4513, 0.4);
        this.scene.add(hemisphereLight);
    }

    async createWorld() {
        // Create ground
        const groundGeometry = new THREE.PlaneGeometry(100, 100);
        const groundMaterial = new THREE.MeshLambertMaterial({ 
            color: 0x7CFC00, // Lawn green
            side: THREE.DoubleSide 
        });
        const ground = new THREE.Mesh(groundGeometry, groundMaterial);
        ground.rotation.x = -Math.PI / 2;
        ground.receiveShadow = true;
        this.scene.add(ground);
        
        // Add some grass texture variation
        const grassTexture = new THREE.MeshLambertMaterial({ 
            color: 0x32CD32, // Lime green
            side: THREE.DoubleSide 
        });
        
        for (let i = 0; i < 200; i++) {
            const grassBlade = new THREE.Mesh(
                new THREE.PlaneGeometry(0.1, 0.5),
                grassTexture
            );
            grassBlade.position.set(
                Math.random() * 80 - 40,
                0.25,
                Math.random() * 80 - 40
            );
            grassBlade.rotation.x = -Math.PI / 2;
            grassBlade.rotation.z = Math.random() * Math.PI;
            this.scene.add(grassBlade);
        }
        
        // Create trees
        for (let i = 0; i < 15; i++) {
            this.createTree(
                Math.random() * 70 - 35,
                Math.random() * 70 - 35
            );
        }
        
        // Create buildings
        this.createBuilding(-15, 0, -15, 8, 12, 8, 0x888888);
        this.createBuilding(15, 0, 15, 6, 8, 6, 0x666666);
        this.createBuilding(-15, 0, 15, 5, 6, 5, 0x777777);
        
        // Create a central fountain
        this.createFountain(0, 0, 0);
        
        // Create some rocks
        for (let i = 0; i < 10; i++) {
            this.createRock(
                Math.random() * 60 - 30,
                Math.random() * 60 - 30
            );
        }
    }

    createTree(x, z) {
        // Tree trunk
        const trunkGeometry = new THREE.CylinderGeometry(0.3, 0.4, 4);
        const trunkMaterial = new THREE.MeshLambertMaterial({ color: 0x8B4513 });
        const trunk = new THREE.Mesh(trunkGeometry, trunkMaterial);
        trunk.position.set(x, 2, z);
        trunk.castShadow = true;
        this.scene.add(trunk);
        
        // Tree leaves
        const leavesGeometry = new THREE.SphereGeometry(2);
        const leavesMaterial = new THREE.MeshLambertMaterial({ color: 0x228B22 });
        const leaves = new THREE.Mesh(leavesGeometry, leavesMaterial);
        leaves.position.set(x, 5, z);
        leaves.castShadow = true;
        this.scene.add(leaves);
    }

    createBuilding(x, y, z, width, height, depth, color) {
        const geometry = new THREE.BoxGeometry(width, height, depth);
        const material = new THREE.MeshLambertMaterial({ color: color });
        const building = new THREE.Mesh(geometry, material);
        building.position.set(x, height / 2, z);
        building.castShadow = true;
        building.receiveShadow = true;
        this.scene.add(building);
        
        // Add windows
        const windowMaterial = new THREE.MeshLambertMaterial({ color: 0x87CEEB });
        for (let i = 0; i < 3; i++) {
            for (let j = 0; j < 2; j++) {
                const window = new THREE.Mesh(
                    new THREE.PlaneGeometry(0.8, 0.8),
                    windowMaterial
                );
                window.position.set(
                    x + (j - 0.5) * (width - 1),
                    y + 2 + i * 2.5,
                    z + depth / 2 + 0.1
                );
                window.rotation.y = Math.PI;
                this.scene.add(window);
            }
        }
    }

    createFountain(x, y, z) {
        // Fountain base
        const baseGeometry = new THREE.CylinderGeometry(3, 3, 0.5, 32);
        const baseMaterial = new THREE.MeshLambertMaterial({ color: 0xCCCCCC });
        const base = new THREE.Mesh(baseGeometry, baseMaterial);
        base.position.set(x, 0.25, z);
        base.receiveShadow = true;
        this.scene.add(base);
        
        // Fountain center
        const centerGeometry = new THREE.CylinderGeometry(1, 1.2, 2, 32);
        const centerMaterial = new THREE.MeshLambertMaterial({ color: 0xDDDDDD });
        const center = new THREE.Mesh(centerGeometry, centerMaterial);
        center.position.set(x, 1.5, z);
        center.castShadow = true;
        this.scene.add(center);
        
        // Water (animated)
        const waterGeometry = new THREE.CylinderGeometry(1.2, 1.2, 0.2, 32);
        const waterMaterial = new THREE.MeshLambertMaterial({ 
            color: 0x4F94CD,
            transparent: true,
            opacity: 0.7
        });
        const water = new THREE.Mesh(waterGeometry, waterMaterial);
        water.position.set(x, 1.1, z);
        water.userData = { type: 'fountain', animate: true };
        this.scene.add(water);
        this.interactiveObjects.push(water);
    }

    createRock(x, z) {
        const geometry = new THREE.SphereGeometry(0.5 + Math.random() * 0.5, 6, 6);
        const material = new THREE.MeshLambertMaterial({ color: 0x696969 });
        const rock = new THREE.Mesh(geometry, material);
        rock.position.set(x, 0.5, z);
        rock.rotation.set(
            Math.random() * Math.PI,
            Math.random() * Math.PI,
            Math.random() * Math.PI
        );
        rock.castShadow = true;
        this.scene.add(rock);
    }

    async addInteractiveObjects() {
        // Create interactive squirrel NPC
        this.createSquirrel(10, 0, 0);
        
        // Create treasure chest
        this.createTreasureChest(-10, 0, 10);
        
        // Create signpost
        this.createSignpost(15, 0, -15);
    }

    createSquirrel(x, y, z) {
        // Squirrel body
        const bodyGeometry = new THREE.SphereGeometry(0.4, 16, 16);
        const bodyMaterial = new THREE.MeshLambertMaterial({ color: 0xFF8C00 });
        const body = new THREE.Mesh(bodyGeometry, bodyMaterial);
        body.position.set(x, y + 0.4, z);
        
        // Squirrel head
        const headGeometry = new THREE.SphereGeometry(0.3, 16, 16);
        const head = new THREE.Mesh(headGeometry, bodyMaterial);
        head.position.set(x, y + 0.8, z + 0.3);
        
        // Squirrel tail
        const tailGeometry = new THREE.SphereGeometry(0.25, 16, 16);
        const tail = new THREE.Mesh(tailGeometry, bodyMaterial);
        tail.position.set(x, y + 0.4, z - 0.5);
        tail.scale.set(1.5, 0.8, 2);
        
        const squirrel = new THREE.Group();
        squirrel.add(body);
        squirrel.add(head);
        squirrel.add(tail);
        squirrel.userData = { 
            type: 'squirrel', 
            interactive: true,
            message: "Hello! I'm your friendly squirrel guide. Explore the playground and find hidden treasures!"
        };
        squirrel.castShadow = true;
        
        this.scene.add(squirrel);
        this.interactiveObjects.push(squirrel);
    }

    createTreasureChest(x, y, z) {
        const chestGeometry = new THREE.BoxGeometry(1.5, 0.8, 1);
        const chestMaterial = new THREE.MeshLambertMaterial({ color: 0xDAA520 });