几何体其实就是由一系列的顶点组成，我们在坐标系打几个点看看：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<script src="http://www.yanhuangxueyuan.com/versions/threejsR92/build/three.js"></script>
</head>
<body>
<div id="webgl"></div>
</body>
</html>
<script>
var scene = new THREE.Scene();
var axes = new THREE.AxesHelper(200);//50表示xyz轴的长度，红:x,绿:y,蓝:z
scene.add(axes);//添加坐标轴
var geometry = new THREE.BufferGeometry(); //创建一个Buffer类型几何体对象
var vertices = new Float32Array([
0, 0, 0, //顶点1坐标
50, 0, 0, //顶点2坐标
0, 100, 0, //顶点3坐标
0, 0, 10, //顶点4坐标
0, 0, 100, //顶点5坐标
50, 0, 10, //顶点6坐标
]);
//创建属性缓冲区对象
var attr = new THREE.BufferAttribute(vertices, 3);//3个为一组，表示一个顶点的xyz坐标
geometry.attributes.position = attr;
// 点渲染模式
var material = new THREE.PointsMaterial({
color: 0xffff00,
size: 10.0 //点对象像素尺寸
}); //材质对象
var points = new THREE.Points(geometry, material); //点模型对象
scene.add(points); //点对象添加到场景中
//创建相机对象
var camera = new THREE.PerspectiveCamera(45, 2, 0.1, 2000);
camera.position.set(300, 300, 100); //设置相机位置
camera.lookAt(scene.position); //设置相机方向(指向的场景对象)
/**
* 创建渲染器对象
*/
var renderer = new THREE.WebGLRenderer({
antialias: true //消除锯齿
});
renderer.setSize(1000, 500);//设置渲染区域尺寸
renderer.setClearColor(0xb9d3ff, 1); //设置背景颜色
renderer.render(scene, camera);//渲染必须有场景和相机两个对象
var cont = document.getElementById('webgl');
cont.appendChild(renderer.domElement);
</script>
point.png
我们将顶点连起来：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<script src="http://www.yanhuangxueyuan.com/versions/threejsR92/build/three.js"></script>
</head>
<body>
<div id="webgl"></div>
</body>
</html>
<script>
var scene = new THREE.Scene();
var axes = new THREE.AxesHelper(200);//50表示xyz轴的长度，红:x,绿:y,蓝:z
scene.add(axes);//添加坐标轴
var geometry = new THREE.BufferGeometry(); //创建一个Buffer类型几何体对象
var vertices = new Float32Array([
0, 0, 0, //顶点1坐标
50, 0, 0, //顶点2坐标
0, 100, 0, //顶点3坐标
0, 0, 10, //顶点4坐标
0, 0, 100, //顶点5坐标
50, 0, 10, //顶点6坐标
]);
//创建属性缓冲区对象
var attr = new THREE.BufferAttribute(vertices, 3);//3个为一组，表示一个顶点的xyz坐标
geometry.attributes.position = attr;
// 线条渲染模式
var material = new THREE.LineBasicMaterial({
color: 0xffff00 //线条颜色
});//材质对象
var line = new THREE.Line(geometry, material);//线条模型对象
scene.add(line);//线条对象添加到场景中
//创建相机对象
var camera = new THREE.PerspectiveCamera(45, 2, 0.1, 2000);
camera.position.set(300, 300, 100); //设置相机位置
camera.lookAt(scene.position); //设置相机方向(指向的场景对象)
/**
* 创建渲染器对象
*/
var renderer = new THREE.WebGLRenderer({
antialias: true //消除锯齿
});
renderer.setSize(1000, 500);//设置渲染区域尺寸
renderer.setClearColor(0xb9d3ff, 1); //设置背景颜色
renderer.render(scene, camera);//渲染必须有场景和相机两个对象
var cont = document.getElementById('webgl');
cont.appendChild(renderer.domElement);
</script>
line.png
如果将这些点连起来形成面：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<script src="http://www.yanhuangxueyuan.com/versions/threejsR92/build/three.js"></script>
</head>
<body>
<div id="webgl"></div>
</body>
</html>
<script>
var scene = new THREE.Scene();
var axes = new THREE.AxesHelper(200);//50表示xyz轴的长度，红:x,绿:y,蓝:z
scene.add(axes);//添加坐标轴
var geometry = new THREE.BufferGeometry(); //创建一个Buffer类型几何体对象
var vertices = new Float32Array([
0, 0, 0, //顶点1坐标
50, 0, 0, //顶点2坐标
0, 100, 0, //顶点3坐标
0, 0, 10, //顶点4坐标
0, 0, 100, //顶点5坐标
50, 0, 10, //顶点6坐标
]);
//创建属性缓冲区对象
var attr = new THREE.BufferAttribute(vertices, 3);//3个为一组，表示一个顶点的xyz坐标
geometry.attributes.position = attr;
// 三角面(网格)渲染模式
var material = new THREE.PointsMaterial({
color: 0xffff00, //三角面颜色
}); //材质对象
var mesh = new THREE.Mesh(geometry, material); //网格模型对象Mesh
scene.add(mesh);
//创建相机对象
var camera = new THREE.PerspectiveCamera(45, 2, 0.1, 2000);
camera.position.set(300,300, 100); //设置相机位置
camera.lookAt(scene.position); //设置相机方向(指向的场景对象)
/**
* 创建渲染器对象
*/
var renderer = new THREE.WebGLRenderer({
antialias: true //消除锯齿
});
renderer.setSize(1000, 500);//设置渲染区域尺寸
renderer.setClearColor(0xb9d3ff, 1); //设置背景颜色
renderer.render(scene, camera);//渲染必须有场景和相机两个对象
var cont = document.getElementById('webgl');
cont.appendChild(renderer.domElement);
</script>
polygon.png
