需要电子档书籍或者源码可以Q群：828202939 希望可以和大家一起学习、一起进步！！
如有错别字或有理解不到位的地方，可以留言或者加微信15250969798，博主会及时修改！！！！！
博主的案例并不难，只是为了更好的给想入门threeJS的同学一点点经验！！！！！
涉及的知识点博主已经从three源码库里面摘要出来放在对应的注释里面！
前面学习了常见的几种格式的模型加载，只要选择对应的加载器加载，获取对应的geometry和material就基本可以还原模型了！
后面博主会考虑把loader加载的模型格式补全！
今天我们学习geometry类的BufferGeometry，buffergeometry是自由度最高的一种geometry，它可以自定义顶点、颜色、法线等属性！
本案例是根据顶点生成三角形再组合成一个几何体！
图示：
代码：
<html>
<head>
<title>threeJS20-geometry-buffergeometry</title>
<style>
body {
background-color: #000;
margin: 0px;
overflow: hidden;
}
#WebGL {
width: 100%;
height: 100%;
position: absolute;
left: 0;
top: 0;
z-index: 999;
}
</style>
</head>
<body>
<script src="http://libs.baidu.com/jquery/2.0.0/jquery.js"></script>
<script src="../../../build/three.js"></script>
<script src="../../js/controls/OrbitControls.js"></script>
<div id="WebGL"></div>
<script>
'use strict';
var container, camera, scene, renderer, geometry, material, animate, controls; //常用变量
var spotLight, mshStdBox, mesh; //自定义对象变量
var target = new THREE.Vector3(0, 30, 0);
var webGLW = $('#WebGL').width();
var webGLH = $('#WebGL').height();
init();
animate();
function init() {
container = document.getElementById('WebGL');
scene = new THREE.Scene();
scene.background = new THREE.Color(0xcfcfcf);
// scene.fog = new THREE.Fog(0xa0a0a0, 2000, 3500); //雾
camera = new THREE.PerspectiveCamera(40, window.innerWidth / window.innerHeight, 0.1, 10000);
camera.position.set(0, 60, -1000);
camera.lookAt(target);
var ambient = new THREE.AmbientLight(0x444444 );
scene.add(ambient);
lights(); //灯光：聚光灯
// lightsHelper(spotLight); //灯光显示助手
// plane() //// 地面
loadModel(); //添加模型
rendererScene(); //场景渲染
OrbitControls(camera, renderer); //OrbitControls控件模块，90版本鼠标右键上下是移动，96版本之后右键上下是缩放
window.addEventListener('resize', onWindowResize, false); //监听屏幕变化
}
function plane() {
// 地面
let grid_mesh = new THREE.Mesh(new THREE.PlaneBufferGeometry(2000, 2000), new THREE.MeshPhongMaterial({
color: 0x999999,
depthWrite: false
}));
grid_mesh.rotation.x = -Math.PI / 2;
grid_mesh.receiveShadow = true;
scene.add(grid_mesh);
var grid = new THREE.GridHelper(2000, 20, 0x000000, 0x000000);
grid.material.opacity = 0.2;
grid.material.transparent = true;
scene.add(grid);
}
function lights() {
// SpotLight( color：颜色, intensity：强度, distance：发光距离, angle：角度, penumbra：边缘范围, decay：衰减 )
spotLight = new THREE.DirectionalLight(0xffffff, 1);
spotLight.position.set(10, 120, -30);
spotLight.angle = Math.PI / 4;
spotLight.penumbra = 0.05; //边缘范围，反比
spotLight.decay = 2; //衰减系数，反比
spotLight.distance = 2000; //发光距离
spotLight.castShadow = true; //阴影
spotLight.shadow.mapSize.width = 1024;
spotLight.shadow.mapSize.height = 1024;
spotLight.shadow.camera.near = 10; //近截面
spotLight.shadow.camera.far = 2500;
scene.add(spotLight);
}
function lightsHelper(lightsObject) {
// 聚光灯显示助手SpotLightHelper( light:灯光, color：颜色 )
var lightHelper = new THREE.SpotLightHelper(lightsObject, 0xdfdfdf);
scene.add(lightHelper);
var mesh = new THREE.Mesh(new THREE.PlaneBufferGeometry(200, 200), new THREE.MeshPhongMaterial({
color: 0x9cfcf99,
depthWrite: false
}));
mesh.rotation.x = -Math.PI / 2;
mesh.position.set(0, -20, 0)
mesh.receiveShadow = true;
scene.add(mesh);
}
function loadModel() { //模型
var triangles = 160000;//三角形数量
var geometry = new THREE.BufferGeometry();
var positions = [];
var normals = [];
var colors = [];
var color = new THREE.Color();
var n = 400,
n2 = n / 2; // 三角形在立方体中展开
var d = 12,
d2 = d / 2; // 单个三角形大小
var pA = new THREE.Vector3();
var pB = new THREE.Vector3();
var pC = new THREE.Vector3();
var cb = new THREE.Vector3();
var ab = new THREE.Vector3();
for (var i = 0; i < triangles; i++) {
// 位置
var x = Math.random() * n - n2;
var y = Math.random() * n - n2;
var z = Math.random() * n - n2;
var ax = x + Math.random() * d - d2;
var ay = y + Math.random() * d - d2;
var az = z + Math.random() * d - d2;
var bx = x + Math.random() * d - d2;
var by = y + Math.random() * d - d2;
var bz = z + Math.random() * d - d2;
var cx = x + Math.random() * d - d2;
var cy = y + Math.random() * d - d2;
var cz = z + Math.random() * d - d2;
positions.push(ax, ay, az);
positions.push(bx, by, bz);
positions.push(cx, cy, cz);
// 平面法线
pA.set(ax, ay, az);
pB.set(bx, by, bz);
pC.set(cx, cy, cz);
cb.subVectors(pC, pB);
ab.subVectors(pA, pB);
cb.cross(ab);
cb.normalize();//标准化
var nx = cb.x;
var ny = cb.y;
var nz = cb.z;
normals.push(nx, ny, nz);
normals.push(nx, ny, nz);
normals.push(nx, ny, nz);
// colors
var vx = (x / n) + 0.5;
var vy = (y / n) + 0.5;
var vz = (z / n) + 0.5;
color.setRGB(vx, vy, vz);
colors.push(color.r, color.g, color.b);
colors.push(color.r, color.g, color.b);
colors.push(color.r, color.g, color.b);
}
function disposeArray() {//释放缓存
this.array = null;
}
// addAttribute ( name : String, attribute : BufferAttribute )
// .onUpload ( callback : Function )一个回调函数
geometry.addAttribute('position', new THREE.Float32BufferAttribute(positions, 3).onUpload(disposeArray));
geometry.addAttribute('normal', new THREE.Float32BufferAttribute(normals, 3).onUpload(disposeArray));
geometry.addAttribute('color', new THREE.Float32BufferAttribute(colors, 3).onUpload(disposeArray));
geometry.computeBoundingSphere();
var material = new THREE.MeshPhongMaterial({
color: 0xaaaaaa,
specular: 0xffffff,
shininess: 250,
side: THREE.DoubleSide,
vertexColors: THREE.VertexColors
});
mesh = new THREE.Mesh(geometry, material);
scene.add(mesh);
}
function onWindowResize() {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize(window.innerWidth, window.innerHeight);
}
function rendererScene() {
renderer = new THREE.WebGLRenderer({
antialias: true
});
renderer.setPixelRatio(window.devicePixelRatio);
renderer.setSize(window.innerWidth, window.innerHeight);
renderer.shadowMap.enabled = true;
renderer.shadowMap.type = THREE.PCFSoftShadowMap;
renderer.gammaInput = true;
renderer.gammaOutput = true;
container.appendChild(renderer.domElement);
}
function OrbitControls(camera, renderer) {
//OrbitControls控件操作模块
controls = new THREE.OrbitControls(camera, renderer.domElement);
controls.target = target; //控制的target
controls.autoRotate = true; //是否自动旋转
controls.autoRotateSpeed = 0.5; //自动旋转速度，正比
}
function animate() {
requestAnimationFrame(animate);
if (controls) controls.update();
renderer.render(scene, camera);
};
</script>
</body>
</html>