三.js HTML 背景为 clearColor

Question

我想在 three.js 中将 HTML 背景设置为 clearColor？

这是我的 three.js 代码：

// init
var vWebGL = new WEBGL();
var scene = new THREE.Scene();
var camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000);
var renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);
var geometry = new THREE.BoxGeometry(1, 1, 1);
var material = new THREE.MeshBasicMaterial({ color: 0x00fdf0 });
var cube = new THREE.Mesh(geometry, material);
scene.add(cube);

camera.position.z = 5;
renderer.clearColor(0x000000, 0.0);

// Render Loop
function animate() {
    renderer.setClearAlpha(0.0);
    requestAnimationFrame(animate);
    cube.rotation.x += 0.01;
    cube.rotation.y += 0.01;
    renderer.render(scene, camera);
}


if (vWebGL.isWebGLAvailable()) {
    // Initiate function or other initializations here
    animate();
} else {
    var warning = vWebGL.getWebGLErrorMessage();
    document.getElementById('container').appendChild(warning);
}

在我的 Webgl 中，我可以将 HTML 指定为 clearColor。

gl.clearColor(0.0, 0.0, 0.0, 0.0);
gl.clear(gl.DEPTH_BUFFER_BIT | gl.COLOR_BUFFER_BIT);

我的 Webgl：

或

Answer 1

THREE.Scene的背景可以通过设置属性.background来设置：

例如

scene = new THREE.Scene();
scene.background = new THREE.Color(0xff0000); // red

如果你想要一个透明背景，那么THREE.WebGLRenderer 必须用属性{alpha: true} 进行初始化。清除颜色和 alpha 通道必须设置为 0，但这是默认设置：

例如

renderer = new THREE.WebGLRenderer( { alpha: true } ); 
renderer.setClearColor( 0x000000, 0 );

查看在背景图像上绘制立方体的示例：

(function onLoad() {
  var container, loader, camera, scene, renderer, orbitControls;
  
  init();
  animate();

  function init() {
    container = document.getElementById('container');
    
    renderer = new THREE.WebGLRenderer({
      antialias: true,
      alpha: true
    });
    renderer.setClearColor( 0x000000, 0 );
    renderer.setPixelRatio(window.devicePixelRatio);
    renderer.setSize(window.innerWidth, window.innerHeight);
    container.appendChild(renderer.domElement);

    camera = new THREE.PerspectiveCamera(70, window.innerWidth / window.innerHeight, 1, 100);
    camera.position.set(0, 1, -2);

    loader = new THREE.TextureLoader();
    loader.setCrossOrigin("");

    scene = new THREE.Scene();
    scene.add(camera);
    window.onresize = resize;
    
    var ambientLight = new THREE.AmbientLight(0x404040);
    scene.add(ambientLight);

    var directionalLight = new THREE.DirectionalLight( 0xffffff, 0.5 );
    directionalLight.position.set(1,2,1.5);
    scene.add( directionalLight );

    orbitControls = new THREE.OrbitControls(camera);
    
    addGridHelper();
    createModel();

  }

  function createModel() {

    var material = new THREE.MeshPhongMaterial({color:'#b090b0'});
    var geometry = new THREE.BoxGeometry( 1, 1, 1 );

    var mesh = new THREE.Mesh(geometry, material);

    scene.add(mesh);
  }

  function addGridHelper() {
    
    var helper = new THREE.GridHelper(100, 100);
    helper.material.opacity = 0.25;
    helper.material.transparent = true;
    scene.add(helper);

    var axis = new THREE.AxesHelper(1000);
    scene.add(axis);
  }

  function resize() {
    
    var aspect = window.innerWidth / window.innerHeight;
    renderer.setSize(window.innerWidth, window.innerHeight);
    camera.aspect = aspect;
    camera.updateProjectionMatrix();
  }

  function animate() {
    requestAnimationFrame(animate);
    orbitControls.update();
    render();
  }

  function render() {
    renderer.render(scene, camera);
  }
})();

#image-abs { position : absolute; top : 0; left : 0; z-index: -1; width: 100%; height: 100%; }

<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/99/three.min.js"></script>
<script src="https://threejs.org/examples/js/controls/OrbitControls.js"></script>
<img id="image-abs" src="https://raw.githubusercontent.com/Rabbid76/graphics-snippets/master/resource/texture/background.jpg">
<div id="container"></div>