Keep objects looking at camera - camera

Question

guys I know this question has been asked several times, several different ways, but I just can get it to work. Basically I have 2d clouds, but I want the camera to rotate around an object floating above the clouds. The problem is, when im not looking a the face of the clouds u can tell that they are 2d. Soooo i want the the clouds to "look" at the camera where ever it is. I believe my problem stems from how the cloud geometry is called on to the planes, but here take a look. I put the a lookAt function with in my animate function. I hope you can point me in the right direction at least.
Three.js rev. 70...
container.appendChild(renderer.domElement);
camera = new THREE.PerspectiveCamera(fov, aspect, near, far);
camera.position.set(0, 0, 100);
scene.add(camera);
controls = new THREE.OrbitControls( camera );
controls.target.copy( new THREE.Vector3( 0, 0,475) );
controls.minDistance = 50;
controls.maxDistance = 200;
controls.autoRotate = true;
controls.autoRotateSpeed = .2; // 30 seconds per round when fps is 60
controls.minPolarAngle = Math.PI/4; // radians
controls.maxPolarAngle = Math.PI/2; // radians
controls.enableDamping = true;
controls.dampingFactor = 0.25;
clock = new THREE.Clock();
cloudGeometry = new THREE.Geometry();
var texture = THREE.ImageUtils.loadTexture('img/cloud10.png', null, animate);
texture.magFilter = THREE.LinearMipMapLinearFilter;
texture.minFilter = THREE.LinearMipMapLinearFilter;
var fog = new THREE.Fog(0x4584b4, -100, 3000);
cloudMaterial = new THREE.ShaderMaterial({
uniforms: {
"map": {
type: "t",
value: texture
},
"fogColor": {
type: "c",
value: fog.color
},
"fogNear": {
type: "f",
value: fog.near
},
"fogFar": {
type: "f",
value: fog.far
},
},
vertexShader: document.getElementById('vs').textContent,
fragmentShader: document.getElementById('fs').textContent,
depthWrite: false,
depthTest: false,
transparent: true
});
var plane = new THREE.Mesh(new THREE.PlaneGeometry(64, 64));
for (var i = 0; i < 8000; i++) {
plane.position.x = Math.random() * 1000 - 500;
plane.position.y = -Math.random() * Math.random() * 200 - 15;
plane.position.z = i;
plane.rotation.z = Math.random() * Math.PI;
plane.scale.x = plane.scale.y = Math.random() * Math.random() * 1.5 + 0.5;
plane.updateMatrix();
cloudGeometry.merge(plane.geometry, plane.matrix);
}
cloud = new THREE.Mesh(cloudGeometry, cloudMaterial);
scene.add(cloud);
cloud = new THREE.Mesh(cloudGeometry, cloudMaterial);
cloud.position.z = -8000;
scene.add(cloud);
var radius = 100;
var xSegments = 50;
var ySegments = 50;
var geo = new THREE.SphereGeometry(radius, xSegments, ySegments);
var mat = new THREE.ShaderMaterial({
uniforms: {
lightPosition: {
type: 'v3',
value: light.position
},
textureMap: {
type: 't',
value: THREE.ImageUtils.loadTexture("img/maps/moon.jpg")
},
normalMap: {
type: 't',
value: THREE.ImageUtils.loadTexture("img/maps/normal.jpg")
},
uvScale: {
type: 'v2',
value: new THREE.Vector2(1.0, 1.0)
}
},
vertexShader: document.getElementById('vertexShader').textContent,
fragmentShader: document.getElementById('fragmentShader').textContent
});
mesh = new THREE.Mesh(geo, mat);
mesh.geometry.computeTangents();
mesh.position.set(0, 50, 0);
mesh.rotation.set(0, 180, 0);
scene.add(mesh);
}
function onWindowResize() {
renderer.setSize(window.innerWidth, window.innerHeight);
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
}
function animate() {
requestAnimationFrame(animate);
light.orbit(mesh.position, clock.getElapsedTime());
cloud.lookAt( camera );
controls.update(camera);
renderer.render(scene, camera);
}
animate();
window.addEventListener('resize', onWindowResize, false);

Answer 1

just a first guess:
the lookAt function needs Vector3 as parameter. try to use camera.position in the animate function.
cloud.lookAt( camera.position );

Answer 2

first of all, to build 2D objects in a scene that always faces towards the camera, you should use Sprite object, so you don't have to do anything to get this effect. (and have better performance :))
Definition from THREE.org: Sprite - a sprite is a plane in an 3d scene which faces always towards the camera.
var map = THREE.ImageUtils.loadTexture( "sprite.png" );
var material = new THREE.SpriteMaterial( { map: map, color: 0xffffff, fog: true } );
var sprite = new THREE.Sprite( material );
scene.add( sprite );
Please check this example: http://threejs.org/examples/#webgl_points_sprites

Answer 3

I would absolutely agree, I would use Sprite, or even Points, but then, if assign a texture to it, it will render it square-sized. My sprites are animated, and frames cannot be packed in square tiles, cause it would take a lot of space. I might make a mesh and use this lookAt function.