three.js 利用点面绘制几何体
使用BufferGeometry
最终的效果展示
代码部分 ：
首先添加几何体的顶点
var cubeGeometry = new THREE.BufferGeometry();
const vertices = new Float32Array([
10, 10, 10,
-10, 10, 10,
-10, -10, 10,
10, -10, 10,
10, -10, -10,
10, 10, -10,
-10, 10, -10,
-10, -10, -10,
])
cubeGeometry.setAttribute('position', new THREE.BufferAttribute(vertices, 3));
利用顶点的索引关系绘制三角面
var indexes = new Uint16Array([
0, 1, 2,
0, 2, 3,
0, 3, 4,
0, 4, 5,
1, 6, 7,
1, 7, 2,
6, 5, 4,
6, 4, 7,
5, 6, 1,
5, 1, 0,
3, 2, 7,
3, 7, 4,
])
cubeGeometry.index = new THREE.BufferAttribute(indexes, 1);
//初始化存放颜色信息的序列化数组
定义几何体的颜色
//初始化存放颜色信息的序列化数组
const colors = new Float32Array([
1.0, 0.0, 0.0,
0.0, 1.0, 0.0,
0.0, 0.0, 1.0,
0.0, 0.5, 0.5
]);
//设置颜色信息
cubeGeometry.setAttribute('color', new THREE.BufferAttribute(colors, 3));
需要定义一个法向量 ，不然绘制的几何体显示黑色
//生成法向量
cubeGeometry.computeVertexNormals();
全部代码
<!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>Document</title>
</head>
<script src="../../node_modules/three/build/three.js"></script>
<script src="../../node_modules/three/examples/js/controls/OrbitControls.js"></script>
<script src="../../node_modules/three/examples/js/libs/stats.min.js"></script>
<script src="../../node_modules/three/examples/js/libs/dat.gui.min.js"></script>
<body onload="draw();">
<script>
var renderer;
function initRender() {
renderer = new THREE.WebGLRenderer({
antialias: true
});
renderer.setSize(window.innerWidth, window.innerHeight);
//告诉渲染器需要阴影效果
renderer.shadowMap.enabled = true;
renderer.shadowMap.type = THREE.PCFSoftShadowMap; // 默认的是，没有设置的这个清晰 THREE.PCFShadowMap
document.body.appendChild(renderer.domElement);
}
var camera;
function initCamera() {
camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 1000);
camera.position.set(0, 40, 100);
camera.lookAt(new THREE.Vector3(0, 0, 0));
}
var scene;
function initScene() {
scene = new THREE.Scene();
}
//初始化dat.GUI简化试验流程
var gui;
function initGui() {
//声明一个保存需求修改的相关数据的对象
gui = {
lightY: 30, //灯光y轴的位置
cubeX: 25, //立方体的x轴位置
cubeY: 10, //立方体的x轴位置
cubeZ: -5 //立方体的z轴的位置
};
var datGui = new dat.GUI();
//将设置属性添加到gui当中，gui.add(对象，属性，最小值，最大值）
datGui.add(gui, "lightY", 0, 100);
datGui.add(gui, "cubeX", -30, 30);
datGui.add(gui, "cubeY", -30, 30);
datGui.add(gui, "cubeZ", -30, 30);
}
var light;
function initLight() {
scene.add(new THREE.AmbientLight(0x444444));
light = new THREE.PointLight(0xffffff);
light.position.set(15, 30, 10);
//告诉平行光需要开启阴影投射
light.castShadow = true;
scene.add(light);
}
var cube;
function initModel() {
//辅助工具
var helper = new THREE.AxisHelper(10);
scene.add(helper);
// 创建一个立方体
// v6----- v5
// /| /|
// v1------v0|
// | | | |
// | |v7---|-|v4
// |/ |/
// v2------v3
//立方体
var cubeGeometry = new THREE.BufferGeometry();
const vertices = new Float32Array([
10, 10, 10,
-10, 10, 10,
-10, -10, 10,
10, -10, 10,
10, -10, -10,
10, 10, -10,
-10, 10, -10,
-10, -10, -10,
])
cubeGeometry.setAttribute('position', new THREE.BufferAttribute(vertices, 3));
var indexes = new Uint16Array([
0, 1, 2,
0, 2, 3,
0, 3, 4,
0, 4, 5,
1, 6, 7,
1, 7, 2,
6, 5, 4,
6, 4, 7,
5, 6, 1,
5, 1, 0,
3, 2, 7,
3, 7, 4,
])
//初始化存放颜色信息的序列化数组
const colors = new Float32Array([
1.0, 0.0, 0.0,
0.0, 1.0, 0.0,
0.0, 0.0, 1.0,
0.0, 0.5, 0.5
]);
//设置颜色信息
cubeGeometry.setAttribute('color', new THREE.BufferAttribute(colors, 3));
cubeGeometry.index = new THREE.BufferAttribute(indexes, 1);
//生成法向量
cubeGeometry.computeVertexNormals();
var cubeMaterial = new THREE.MeshLambertMaterial({
vertexColors: THREE.VertexColors, //使用缓存中的颜色
side: THREE.DoubleSide
});
cube = new THREE.Mesh(cubeGeometry, cubeMaterial);
cube.position.x = 25;
cube.position.y = 5;
cube.position.z = -5;
//告诉立方体需要投射阴影
cube.castShadow = true;
scene.add(cube);
//底部平面
var planeGeometry = new THREE.PlaneGeometry(100, 100);
var planeMaterial = new THREE.MeshLambertMaterial({
color: 0xaaaaaa
});
var plane = new THREE.Mesh(planeGeometry, planeMaterial);
plane.rotation.x = -0.5 * Math.PI;
plane.position.y = -0;
//告诉底部平面需要接收阴影
plane.receiveShadow = true;
scene.add(plane);
}
//初始化性能插件
var stats;
function initStats() {
stats = new Stats();
document.body.appendChild(stats.dom);
}
//用户交互插件 鼠标左键按住旋转，右键按住平移，滚轮缩放
var controls;
function initControls() {
controls = new THREE.OrbitControls(camera, renderer.domElement);
// 如果使用animate方法时，将此函数删除
//controls.addEventListener( 'change', render );
// 使动画循环使用时阻尼或自转 意思是否有惯性
controls.enableDamping = true;
//动态阻尼系数 就是鼠标拖拽旋转灵敏度
//controls.dampingFactor = 0.25;
//是否可以缩放
controls.enableZoom = true;
//是否自动旋转
controls.autoRotate = false;
//设置相机距离原点的最远距离
controls.minDistance = 50;
//设置相机距离原点的最远距离
controls.maxDistance = 200;
//是否开启右键拖拽
controls.enablePan = true;
}
function render() {
renderer.render(scene, camera);
}
//窗口变动触发的函数
function onWindowResize() {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
render();
renderer.setSize(window.innerWidth, window.innerHeight);
}
function animate() {
//更新控制器
render();
//更新性能插件
stats.update();
//更新相关位置
light.position.y = gui.lightY;
cube.position.x = gui.cubeX;
cube.position.y = gui.cubeY;
cube.position.z = gui.cubeZ;
controls.update();
requestAnimationFrame(animate);
}
function draw() {
initGui();
initRender();
initScene();
initCamera();
initLight();
initModel();
initControls();
initStats();
animate();
window.onresize = onWindowResize;
}
</script>
</body>
</html>