three.js 庫中的材質就已經基本上介紹完了。本篇開始我們將逐個深入 three.js 中各種幾何體的細節。在 three.js 中,常用的幾何體包括:
二維幾何體:
- PlaneGeometry 平面
- CircleGeometry 圓形
- ShapeGeometry 塑形
- BoxGeometry 立方體(或叫三維方塊)
- SphereGeometry 球體
- CylinderGeometry 柱體
- TorusGeometry 圓環
- TorusKnotGeometry 環面扭結
- PolyhedronGeometry 多面體
- IcosahedronGeometry 十二面體
- OctahedronGeometry 八面體
- TetrahedronGeometry 四面體
- ConvexGeometry 凸面體
- LatheGeometry 掃描面
- ExtrudeGeometry 拉伸幾何體
- TubeGeometry 管狀體
- ParametricGeometry 參數幾何體
- TextGeometry 文本幾何體
屬性 | 描述 |
---|---|
width (寬度) | 必選。此屬性指定矩形的寬度 |
height (高度) | 必選。此屬性指定矩形的高度 |
widthSegments (寬度段數) | 可選。此屬性指定矩形的寬度應該劃分成多少段來表示 |
heightSegments (高度段數) | 可選。此屬性指定矩形的高度應該劃分成多少段來表示 |
<!DOCTYPE html>
<html>
<head>
<title>示例 05.01 - PlaneGeometry</title>
<script src="../build/three.js"></script>
<script src="../build/js/controls/OrbitControls.js"></script>
<script src="../build/js/libs/stats.min.js"></script>
<script src="../build/js/libs/dat.gui.min.js"></script>
<script src="../jquery/jquery-3.2.1.min.js"></script>
<style>
body {
/* 設置 margin 爲 0,並且 overflow 爲 hidden,來完成頁面樣式 */
margin: 0;
overflow: hidden;
}
/* 統計對象的樣式 */
#Stats-output {
position: absolute;
left: 0px;
top: 0px;
}
</style>
</head>
<body>
<!-- 用於 WebGL 輸出的 Div -->
<div id="webgl-output"></div>
<!-- 用於統計 FPS 輸出的 Div -->
<div id="stats-output"></div>
<!-- 運行 Three.js 示例的 Javascript 代碼 -->
<script type="text/javascript">
var scene;
var camera;
var render;
var webglRender;
//var canvasRender;
var controls;
var stats;
var guiParams;
var ground;
//var cube;
//var sphere;
var plane;
var meshMaterial;
var ambientLight;
var spotLight;
//var cameraHelper;
$(function() {
stats = initStats();
scene = new THREE.Scene();
webglRender = new THREE.WebGLRenderer( {antialias: true, alpha: true} ); // antialias 抗鋸齒
webglRender.setSize(window.innerWidth, window.innerHeight);
webglRender.setClearColor(0xeeeeee, 1.0);
webglRender.shadowMap.enabled = true; // 允許陰影投射
render = webglRender;
camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 30, 1000); // 2147483647
camera.position.set(-45.5, 68.2, 90.9);
var target = new THREE.Vector3(10, 0 , 0);
controls = new THREE.OrbitControls(camera, render.domElement);
controls.target = target;
camera.lookAt(target);
$('#webgl-output')[0].appendChild(render.domElement);
window.addEventListener('resize', onWindowResize, false);
ambientLight = new THREE.AmbientLight(0x0c0c0c);
scene.add(ambientLight);
spotLight = new THREE.SpotLight(0xffffff);
spotLight.position.set(0, 30, 60);
spotLight.castShadow = true;
scene.add(spotLight);
//cameraHelper = new THREE.CameraHelper(spotLight.shadow.camera);
//scene.add(cameraHelper);
// 加入一個地面
var groundGeometry = new THREE.PlaneGeometry(100, 100, 4, 4);
var groundMaterial = new THREE.MeshBasicMaterial({color: 0x777777});
ground = new THREE.Mesh(groundGeometry, groundMaterial);
ground.rotation.set(-0.5 * Math.PI, 0, 0); // 沿着 X軸旋轉-90°
scene.add(ground);
// 定義 plane
var planeGeometry;
// 材質
meshMaterial = [
new THREE.MeshNormalMaterial({side: THREE.DoubleSide}),
new THREE.MeshBasicMaterial({wireframe: true})
];
/** 用來保存那些需要修改的變量 */
guiParams = new function() {
this.rotationSpeed = 0.02;
this.width = 26;
this.height = 29;
this.widthSegments = 1;
this.heightSegments = 1;
this.update = function() {
scene.remove(plane);
planeGeometry = new THREE.PlaneGeometry(this.width, this.height, this.widthSegments, this.heightSegments);
plane = new THREE.SceneUtils.createMultiMaterialObject(planeGeometry, meshMaterial);
plane.castShadow = true;
plane.position.set(0, 12, 0);
scene.add(plane);
}
}
/** 定義 dat.GUI 對象,並綁定 guiParams 的幾個屬性 */
var gui = new dat.GUI();
var folder = gui.addFolder('Mesh');
folder.open();
folder.add(guiParams, 'width', 1, 50).onChange(function(e) {
guiParams.update();
});
folder.add(guiParams, 'height', 1, 50).onChange(function(e) {
guiParams.update();
});
folder.add(guiParams, 'widthSegments', 1, 10, 1).onChange(function(e) {
guiParams.update();
});
folder.add(guiParams, 'heightSegments', 1, 10, 1).onChange(function(e) {
guiParams.update();
});
guiParams.update();
renderScene();
});
/** 渲染場景 */
function renderScene() {
stats.update();
rotateMesh(); // 旋轉物體
requestAnimationFrame(renderScene);
render.render(scene, camera);
}
/** 初始化 stats 統計對象 */
function initStats() {
stats = new Stats();
stats.setMode(0); // 0 爲監測 FPS;1 爲監測渲染時間
$('#stats-output').append(stats.domElement);
return stats;
}
/** 當瀏覽器窗口大小變化時觸發 */
function onWindowResize() {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
render.setSize(window.innerWidth, window.innerHeight);
}
/** 旋轉物體 */
var step = 0;
function rotateMesh() {
step += guiParams.rotationSpeed;
scene.traverse(function(mesh) {
if (mesh instanceof THREE.Mesh && mesh != ground) {
//mesh.rotation.x = step;
mesh.rotation.y = step;
//mesh.rotation.z = step;
}
});
}
</script>
</body>
</html>
在該實例中(後續幾個示例同理),我們用到了組合材質,一個是 MeshNormalMaterial 法向量材質,並且設置其 side 屬性爲 THREE.DoubleSide。這樣做的目的是,使得當物體背面朝向相機的時候,也要讓我們能看得見它;另一個是 MeshBasicMaterial 基礎材質,通過它來打開線框效果,這樣我們就能看到該物體在三維空間中的具體形狀(譬如寬度段數及高度段數的劃分情況等)。
未完待續···