three.js实现太阳日食原理图
时间: 2023-12-12 12:35:16 浏览: 34
以下是使用Three.js实现太阳日食原理图的步骤:
1.创建场景、相机和渲染器:
```javascript
var scene = new THREE.Scene();
var camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000);
var renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);
```
2.创建太阳和地球的几何体和材质:
```javascript
var sunGeometry = new THREE.SphereGeometry(5, 32, 32);
var sunMaterial = new THREE.MeshBasicMaterial({ color: 0xffff00 });
var sun = new THREE.Mesh(sunGeometry, sunMaterial);
var earthGeometry = new THREE.SphereGeometry(1, 32, 32);
var earthMaterial = new THREE.MeshBasicMaterial({ color: 0x0000ff });
var earth = new THREE.Mesh(earthGeometry, earthMaterial);
```
3.设置太阳和地球的位置:
```javascript
sun.position.set(0, 0, -20);
earth.position.set(0, 0, -30);
```
4.创建一个平面几何体和材质,用于表示地球的投影:
```javascript
var planeGeometry = new THREE.PlaneGeometry(10, 10);
var planeMaterial = new THREE.MeshBasicMaterial({ color: 0x00ff00, side: THREE.DoubleSide });
var plane = new THREE.Mesh(planeGeometry, planeMaterial);
plane.rotation.x = Math.PI / 2;
```
5.将太阳、地球和平面添加到场景中:
```javascript
scene.add(sun);
scene.add(earth);
scene.add(plane);
```
6.设置相机的位置和朝向:
```javascript
camera.position.z = 10;
camera.lookAt(scene.position);
```
7.创建一个函数,用于更新地球和平面的位置,以模拟日食效果:
```javascript
function update() {
var distance = sun.position.distanceTo(earth.position);
var sunRadius = sun.geometry.parameters.radius;
var earthRadius = earth.geometry.parameters.radius;
var angle = Math.acos(sunRadius / distance);
var projectionDistance = distance * Math.sin(angle) - earthRadius;
var projectionPosition = new THREE.Vector3(earth.position.x, earth.position.y, earth.position.z - projectionDistance);
plane.position.copy(projectionPosition);
}
```
8.在渲染循环中调用更新函数,并使用渲染器渲染场景和相机:
```javascript
function render() {
requestAnimationFrame(render);
update();
renderer.render(scene, camera);
}
render();
```