今天我們來用ThreeJS的庫實現一個波紋粒子效果，我們用到的ThreeJS的庫有CanvasRenderer.js，OrbitControls.js，Projector.js，stats.min.js和three.js。這些庫都是不可或缺的，我們先來看看實現的效果，如下圖所示。
我們再來看看項目結構是怎么樣的，項目結構如下圖所示。
我們的效果全部寫在了index.html里，現在我們直接貼出index.html的代碼，同學們可以直接拿來運行，代碼如下。
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>演示頁面</title>
<script src="three.js"></script>
<script src="Projector.js"></script>
<script src="CanvasRenderer.js"></script>
<script src="stats.min.js"></script>
<script src="OrbitControls.js"></script>
</head>
<body>
</body>
<script>
var SEPARATION = 200,
AMOUNTX = 60,
AMOUNTY = 60;
var container, stats;
var camera, scene, renderer, controls;
var particles, particle, count = 0;
var windowHalfX = window.innerWidth / 2;
var windowHalfY = window.innerHeight / 2;
var raycaster = new THREE.Raycaster();
var mouse = new THREE.Vector2();
function init() {
container = document.createElement('div');
document.body.appendChild(container);
camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 1, 10000);
scene = new THREE.Scene();
/**
* 設置光源
* */
//點光源
var point = new THREE.PointLight(0xffffff);//白光
point.position.set(1200, 1200, 1200);//點光源位置
scene.add(point);//點光源添加進場景
//環境光
var ambient = new THREE.AmbientLight(0x999999);//白光
scene.add(ambient);//環境光添加進場景
//模型
var cubeGeometry = new THREE.CubeGeometry(1000, 1000, 1000);
var cubeMaterial = new THREE.MeshLambertMaterial({
color:0xffff00
//side:THREE.DoubleSide
});//材質對象
var cubeMesh = new THREE.Mesh(cubeGeometry, cubeMaterial);//網格模型對象
cubeMesh.translateY(500);
scene.add(cubeMesh);//正方體網格模型添加到場景中
//粒子
particles = new Array();
var PI2 = Math.PI * 2;
var material = new THREE.SpriteCanvasMaterial({
color: 0xffffff,
program: function(context) {
context.beginPath();
context.arc(0, 0, 0.5, 0, PI2, true);
context.fill();
}
});
var i = 0;
for (var ix = 0; ix < AMOUNTX; ix++) {
for (var iy = 0; iy < AMOUNTY; iy++) {
particle = particles[i++] = new THREE.Sprite(material);
particle.position.x = ix * SEPARATION - ((AMOUNTX * SEPARATION) / 2);
particle.position.z = iy * SEPARATION - ((AMOUNTY * SEPARATION) / 2);
scene.add(particle);
}
}
/**
* 創建渲染器對象
* */
renderer = new THREE.CanvasRenderer();
renderer.setPixelRatio(window.devicePixelRatio);
renderer.setSize(window.innerWidth, window.innerHeight);
container.appendChild(renderer.domElement);
window.addEventListener('resize', onWindowResize, false);
//交互控制器
/**
* 鼠標鍵盤事件監聽器
* */
controls = new THREE.OrbitControls(camera, renderer.domElement);
controls.enableDamping = true;
controls.dampingFactor = 0.1;
controls.screenSpacePanning = true;
controls.minDistance = 0;
controls.maxDistance = 5000;
controls.maxPolarAngle = 2*Math.PI;
/**
* 模型拾取
* */
mouse.x = -10000;
mouse.y = -10000;
function onMouseMove( event ) {
// calculate mouse position in normalized device coordinates
// (-1 to +1) for both components
mouse.x = ( event.clientX / window.innerWidth ) * 2 - 1;
mouse.y = - ( event.clientY / window.innerHeight ) * 2 + 1;
}
window.addEventListener( 'mousemove', onMouseMove, false );
}
function pickUp() {
// update the picking ray with the camera and mouse position
raycaster.setFromCamera( mouse, camera );
// calculate objects intersecting the picking ray
var intersects = raycaster.intersectObjects( scene.children );
for ( var i = 0; i < intersects.length; i++ ) {
intersects[ i ].object.material.color.set( 0xff00ff );
}
if(intersects.length === 0){
scene.children[2].material.color.set( 0xffff00 );
for(var i=3; i<scene.children.length; i++){
scene.children[i].material.color.set( 0xffffff );
}
}
renderer.render( scene, camera );
}
function onWindowResize() {
windowHalfX = window.innerWidth / 2;
windowHalfY = window.innerHeight / 2;
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize(window.innerWidth, window.innerHeight);
}
var rad = 0;
function render() {
camera.position.set(2600, 500, 2600);
camera.up = new THREE.Vector3(0, 1, 0);
camera.lookAt(new THREE.Vector3(0, 500, 0));
var i = 0;
for (var ix = 0; ix < AMOUNTX; ix++) {
for (var iy = 0; iy < AMOUNTY; iy++) {
particle = particles[i++];
particle.position.y = (Math.sin((ix + count) * 0.2) * 500) +
(Math.sin((iy + count) * 0.2) * 500);
particle.scale.y = (Math.sin((ix + count) * 0.3) + 1) * 3 +
(Math.sin((iy + count) * 0.3) + 1) * 3;
particle.scale.x = (Math.sin((ix + count) * 0.3) + 1) * 3 +
(Math.sin((iy + count) * 0.3) + 1) * 3;
}
scene.children[2].translateY(Math.cos(ix + count/2)*5);
}
//模型旋轉
scene.children[2].rotateY(Math.PI/180);
camera.position.x = 2600*Math.cos(Math.PI/180*rad);
camera.position.z = -2600*Math.sin(Math.PI/180*rad);
//點光源位置
scene.children[0].position.x = 1200*Math.cos(Math.PI/180*rad+Math.PI*0.1);
scene.children[0].position.z = -1200*Math.sin(Math.PI/180*rad+Math.PI*0.1);
controls.update();
renderer.render(scene, camera);
count += 0.1;
rad += 0.2;
}
function animate() {
requestAnimationFrame(animate);
render();
pickUp();
}
init();
animate();
</script>
</html>
我們分析一下段代碼，首先我們看到requestAnimationFrame，這是主循環，我們在init()初始化函數中往scene場景中添加了particle粒子，這些粒子是在XoZ平面上均勻網格散布的。然后我們主循環每次render()都改變粒子的Y坐標，修改的規則是通過sin函數進行Y軸向擾動。每次重繪我們都修改Y坐標，就實現了粒子的波動特效。
代碼很簡單，希望能幫助大家做出一套粒子波動的背景特效。鯽魚非常願意和大家討論學習WebGL和ThreeJS的技術，歡迎大家留言，謝謝。本文系原創，如需引用請注明出處：https://www.cnblogs.com/ccentry/p/10125686.html