Soft Bodies Physics

// Note: Soft body support depends on the physics engine
// This example uses Ammo.js which has soft body capabilities

// First ensure Ammo.js is properly loaded with soft body support
// <script src="https://cdn.babylonjs.com/ammo.js"></script>

// Create a soft body cloth
async function createSoftBodyCloth() {
    // Wait for Ammo initialization
    await Ammo();
    
    // Create a cloth mesh (plane with subdivisions)
    const cloth = BABYLON.MeshBuilder.CreateGround("cloth", {
        width: 5,
        height: 5,
        subdivisions: 20
    }, scene);
    cloth.position.y = 5;
    
    // Create material for visualization
    const clothMaterial = new BABYLON.StandardMaterial("clothMat", scene);
    clothMaterial.diffuseTexture = new BABYLON.Texture("textures/fabric.jpg", scene);
    clothMaterial.backFaceCulling = false;
    cloth.material = clothMaterial;
    
    // Physics initialization with Ammo.js
    scene.enablePhysics(new BABYLON.Vector3(0, -9.81, 0), new BABYLON.AmmoJSPlugin());
    
    // Configure soft body parameters
    const softBodyHelperOptions = {
        fixedPoints: [0, 1, 20, 21], // Fix the top corners (depends on subdivision)
        mass: 1,
        pressure: 100,
        stiffness: 0.1,
        friction: 0.8
    };
    
    // Create the soft body impostor with Ammo.js
    cloth.physicsImpostor = new BABYLON.PhysicsImpostor(
        cloth,
        BABYLON.PhysicsImpostor.SoftImpostor,
        softBodyHelperOptions,
        scene
    );
    
    // Add collision with other objects
    const sphere = BABYLON.MeshBuilder.CreateSphere("sphere", {
        diameter: 1
    }, scene);
    sphere.position = new BABYLON.Vector3(0, 2, 0);
    sphere.physicsImpostor = new BABYLON.PhysicsImpostor(
        sphere,
        BABYLON.PhysicsImpostor.SphereImpostor,
        { mass: 2, restitution: 0.7 },
        scene
    );
    
    // Apply wind force to the cloth
    let time = 0;
    scene.onBeforeRenderObservable.add(() => {
        time += scene.getEngine().getDeltaTime() / 1000;
        
        // Oscillating wind force
        const windStrength = 5 + Math.sin(time * 0.5) * 4;
        const windDirection = new BABYLON.Vector3(Math.sin(time * 0.2), 0, Math.cos(time * 0.2));
        
        // Apply wind to soft body
        cloth.physicsImpostor.applyForce(
            windDirection.scale(windStrength),
            cloth.position
        );
    });
}

// Call the function to create the soft body
createSoftBodyCloth();