samien
/
three.js
зеркало из https://github.com/mrdoob/three.js.git


			
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    <title>绘制线条</title>
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        <h1>绘制线条</h1>
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          <p>
            假设你想绘制一条线或一个圆，而不是线框 `Mesh`。
            首先我们需要设置渲染器、场景和相机（参见"创建场景"页面）。
          </p>

          <p>以下是我们将使用的代码：</p>
<pre class="prettyprint notranslate lang-js" translate="no">
const renderer = new THREE.WebGLRenderer();
renderer.setSize( window.innerWidth, window.innerHeight );
document.body.appendChild( renderer.domElement );

const camera = new THREE.PerspectiveCamera( 45, window.innerWidth / window.innerHeight, 1, 500 );
camera.position.set( 0, 0, 100 );
camera.lookAt( 0, 0, 0 );

const scene = new THREE.Scene();
</pre>
          <p>接下来我们需要定义一个材质。对于线条，需要使用 `LineBasicMaterial` 或 `LineDashedMaterial`。</p>
<pre class="prettyprint notranslate lang-js" translate="no">
// 创建一个蓝色的 LineBasicMaterial
const material = new THREE.LineBasicMaterial( { color: 0x0000ff } );
</pre>

          <p>
            有了材质之后，我们还需要一个带有顶点的几何体：
          </p>

<pre class="prettyprint notranslate lang-js" translate="no">
const points = [];
points.push( new THREE.Vector3( - 10, 0, 0 ) );
points.push( new THREE.Vector3( 0, 10, 0 ) );
points.push( new THREE.Vector3( 10, 0, 0 ) );

const geometry = new THREE.BufferGeometry().setFromPoints( points );
</pre>

          <p>注意，线条是在每对相邻顶点之间绘制的，而不会连接首尾两个顶点（即线条不是闭合的）。</p>

          <p>现在我们有了两条线段的顶点和一个材质，可以将它们组合成一条线：</p>
<pre class="prettyprint notranslate lang-js" translate="no">
const line = new THREE.Line( geometry, material );
</pre>
          <p>剩下的就是将其添加到场景中并调用 `renderer.render()`。</p>

<pre class="prettyprint notranslate lang-js" translate="no">
scene.add( line );
renderer.render( scene, camera );
</pre>

          <p>现在你应该能看到一个由两条蓝色线段组成的向上箭头。</p>

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