PROWAREtech
ThreeJS: Create an Egg
How to create a 3D egg object/geometry/mesh using the THREE.js LatheGeometry.
An egg is a complex shape to form. In the below function, the egg's shape can be changed by modifying the girth variable by only slight amounts unless looking for a shape other than an egg.
var createEgg = function () {
var arr = [], girth = 0.719, apex = girth * 0.111111111; // fine-tune girth value
for (var rad = 0; rad <= Math.PI; rad += 0.1047) { // 0.1047 radians == 6 degrees
var v = new THREE.Vector2((apex * Math.cos(rad) + girth) * Math.sin(rad), - Math.cos(rad));
arr.push(v);
}
return new THREE.Mesh(
new THREE.LatheGeometry(arr, 24),
new THREE.MeshLambertMaterial({ color: 0xF0EAD6 }) // NOTE: natural eggshell is #F0EAD6
);
};
Here is a working example:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>An Egg</title>
<style>
canvas {
display: block;
width: 300px;
height: 300px;
}
</style>
</head>
<body>
<canvas></canvas>
<script src="/js/three.min.js"></script>
<script type="text/javascript">
(function () {
var createEgg = function () {
var arr = [], girth = 0.719, apex = girth * 0.111111111; // fine-tune girth value
for (var rad = 0; rad <= Math.PI; rad += 0.1047) { // 0.1047 radians == 6 degrees
var v = new THREE.Vector2((apex * Math.cos(rad) + girth) * Math.sin(rad), - Math.cos(rad));
arr.push(v);
}
return new THREE.Mesh(
new THREE.LatheGeometry(arr, 24),
new THREE.MeshLambertMaterial({ color: 0xF0EAD6 }) // NOTE: natural eggshell is #F0EAD6
);
};
var canvas = document.getElementsByTagName("canvas")[0];
// NOTE: create the scene to place objects in
var scene = new THREE.Scene();
scene.background = new THREE.Color(0x6699CC); // NOTE: make the background blue for the sky
scene.matrixWorldAutoUpdate = true;
// NOTE: the width and height of the canvas
var size = {
width: canvas.offsetWidth,
height: canvas.offsetHeight
};
var cameraNear = 1, cameraFar = 5000;
// NOTE: create the camera with 53 degree field of view; this is how the scene is viewed by the user
var camera = new THREE.PerspectiveCamera(53, size.width / size.height, cameraNear, cameraFar);
// NOTE: position the camera in space a bit
camera.position.z = 3;
var renderer = new THREE.WebGLRenderer({
canvas: canvas,
antialias: true
});
renderer.setPixelRatio(window.devicePixelRatio);
renderer.setSize(size.width, size.height);
renderer.render(scene, camera);
var light = new THREE.DirectionalLight(0xffffff, 1);
light.position.set(2, 2, 2);
scene.add(light);
scene.add(new THREE.AmbientLight(0xffffff, .3)); // NOTE: add a touch of ambient light
var egg = createEgg();
scene.add(egg);
// NOTE: MUST HAVE AN ANIMATE FUNCTION
var animate = function () {
renderer.render(scene, camera);
requestAnimationFrame(animate);
};
animate();
})();
</script>
</body>
</html>
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