​

var theta = 0,

    numCollisions = 0;

​

init();

render();

​

function init() {

​

    scene = new THREE.Scene();

​

    camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 10000);

    camera.position.z = 1000;

    camera.position.x = 200;

    camera.position.y = 50;

    camera.lookAt(scene.position);

    scene.add(camera);

​

    var pointLight = new THREE.DirectionalLight(0xbbbbbb);

    pointLight.position.set(100, 100, 500);

    scene.add(pointLight);

​

    var ambientLight = new THREE.AmbientLight(0xbbbbbb);

    scene.add(ambientLight);

​

    sphereGeometry = new THREE.SphereGeometry(200, 64, 64);

    sphereMaterial = new THREE.MeshPhongMaterial({

        color: 'darkgreen',

        opacity: 0.5,

        transparent: true

    });

​

    sphereMesh = new THREE.Mesh(sphereGeometry, sphereMaterial);

    scene.add(sphereMesh);

​

    planeGeometry = new THREE.PlaneGeometry(100, 100, 10, 10);

    planeGeometry.dynamic = true;

​

    planeMaterial = new THREE.MeshPhongMaterial({

        color: 'blue'

    });

​

    planeMesh = new THREE.Mesh(planeGeometry, planeMaterial);

    planeMesh.material.side = THREE.DoubleSide;

    planeMesh.position.z = 201;

    planeMesh.position.y = 50;

​

    for (var vertexIndex = 0; vertexIndex < planeMesh.geometry.vertices.length; vertexIndex++) {

​

        var localVertex = planeMesh.geometry.vertices[vertexIndex].clone();

        var rayStart = new THREE.Vector3(0, 0, 500);

        var ray = new THREE.Raycaster(rayStart, new THREE.Vector3(0, 0, -1));

​

        var collisionResults = ray.intersectObject(sphereMesh);

        numCollisions += collisionResults.length;

​

        if (collisionResults.length > 0) {

​

            planeMesh.geometry.vertices[vertexIndex].z = collisionResults[0].point.z - 1;

        }

    }

​

    $('#Text').text('Number of collisions: ' + numCollisions);

​

    planeMesh.geometry.verticesNeedUpdate = true;

    planeMesh.geometry.normalsNeedUpdate = true;

​

    scene.add(planeMesh);

​

    var axes = new THREE.AxisHelper(500);

    scene.add(axes);

​

    renderer = new THREE.WebGLRenderer({

        alpha: true

    });

    renderer.setSize(window.innerWidth, window.innerHeight);

​

    document.body.appendChild(renderer.domElement);

}

​

function render() {

​

    renderer.render(scene, camera);

​

    camera.position.x = 1000 * Math.cos(theta);

    camera.position.y = 10;

    camera.position.z = 1000 * Math.sin(theta);

​

    camera.lookAt(scene.position);

​

    requestAnimationFrame(render);

}

​

document.addEventListener('keydown', function (e) {

    var key = e.keyCode;

​

    switch (key) {

        case 37:

​

            theta += 0.1;

            break;

​

        case 39:

​

            theta -= 0.1;

            break;

    }

}, false);