如何在three.js中设置图像背景？

Question

我正在尝试在Three.js中为带有Globe的场景设置图像背景，但是不幸的是，当我这样做时，场景的主要对象也变成了黑色（与背景颜色相同）。

我用的方法：

renderer = new THREE.WebGLRenderer({ antialias: false, alpha:true });

这使默认背景透明。 然后在CSS部分中添加了图片背景。

我的整个场景脚本如下所示：

        var container, stats;
        var camera, scene, renderer;
        var group;
        var mouseX = 0, mouseY = 0;

        var windowHalfX = window.innerWidth / 2;
        var windowHalfY = window.innerHeight / 2;

        init();
        animate();


        function init() {

            container = document.getElementById( 'container' );

            camera = new THREE.PerspectiveCamera( 60, window.innerWidth / window.innerHeight, 1, 2000 );
            //closer
            camera.position.z = 500;

            scene = new THREE.Scene();

            group = new THREE.Group();
            scene.add( group );

            // earth

            var loader = new THREE.TextureLoader();
            loader.load( 'textures/mapnew1.jpg', function ( texture ) {

                var geometry = new THREE.SphereGeometry( 180, 32, 32 );

                var material = new THREE.MeshBasicMaterial( { map: texture, overdraw: 0.5 } );
                var mesh = new THREE.Mesh( geometry, material );
                group.add( mesh );

            } );



            // shadow

            var canvas = document.createElement( 'canvas' );
            canvas.width = 128;
            canvas.height = 128;

            var context = canvas.getContext( '2d' );
            var gradient = context.createRadialGradient(
                canvas.width / 2,
                canvas.height / 2,
                0,
                canvas.width / 2,
                canvas.height / 2,
                canvas.width / 2
            );
            gradient.addColorStop( 0.1, '#000000' );
            gradient.addColorStop( 1, '#000000' );

            context.fillStyle = gradient;
            context.fillRect( 0, 0, canvas.width, canvas.height );

            var texture = new THREE.CanvasTexture( canvas );

            var geometry = new THREE.PlaneBufferGeometry( 300, 300, 3, 3 );
            var material = new THREE.MeshBasicMaterial( { map: texture, overdraw: 0.5 } );


            var mesh = new THREE.Mesh( geometry, material );
            mesh.position.y = - 200;
            mesh.rotation.x = - Math.PI / 2;
            group.add( mesh );


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

            stats = new Stats();
            container.appendChild( stats.dom );

            document.addEventListener( 'mousemove', onDocumentMouseMove, false );

            //

            window.addEventListener( 'resize', onWindowResize, false );

        }

        function onWindowResize() {

            windowHalfX = window.innerWidth / 2;
            windowHalfY = window.innerHeight / 2;

            camera.aspect = window.innerWidth / window.innerHeight;
            camera.updateProjectionMatrix();

            renderer.setSize( window.innerWidth, window.innerHeight );

        }

        function onDocumentMouseMove( event ) {

            mouseX = ( event.clientX - windowHalfX );
            mouseY = ( event.clientY - windowHalfY );

        }

        //

        function animate() {

            requestAnimationFrame( animate );

            render();
            stats.update();

        }


        function render() {

            camera.position.x += ( mouseX - camera.position.x ) * 0.08;
            camera.position.y += ( - mouseY - camera.position.y ) * 0.08;
            camera.lookAt( scene.position );

            group.rotation.y -= 0.003;

            renderer.render( scene, camera );


        }


    </script>

这是我的CSS：

body {
  color: #ffffff;
  font-family:'Futura';
  font-size:20px;
  text-align: center;
  background-image: url(textures/starfield.png);
  background-color: black;
  margin: 0px;
  overflow: hidden;
}

您有任何解决办法，如何使地球可见？

非常感谢你！

Answer 1

一段时间以来，有：

var texture = new THREE.TextureLoader().load( "textures/bg.jpg" );
scene.background = texture;

我正在使用three.js v 0.87

Answer 2

关于背景图像，您正在为WebGLRenderer设置alpha值，这是正确的。 您没有发布CSS，但是请确保将背景图片设置在container ，而不是画布上。

另外，注释掉这一行：

renderer.setClearColor(0x000000, 0);

您不需要设置清晰的颜色，因为您要透明而不是颜色。 那应该解决背景图像问题。

对于全黑模型，您需要在场景中有灯光。 尝试将其添加到您的init方法中：

var light = new THREE.PointLight(0xffffff, 1, Infinity);
camera.add(light);

这将在相机的位置添加一个光源（并在相机移动时跟随它）。

编辑以添加代码段：

 var container, stats; var camera, scene, renderer; var group; var mouseX = 0, mouseY = 0; var windowHalfX = window.innerWidth / 2; var windowHalfY = window.innerHeight / 2; init(); animate(); function init() { container = document.getElementById('container'); camera = new THREE.PerspectiveCamera(60, window.innerWidth / window.innerHeight, 1, 2000); //closer camera.position.z = 500; var light = new THREE.PointLight(0xffffff, 1, Infinity); camera.add(light); scene = new THREE.Scene(); group = new THREE.Group(); scene.add(group); // earth var loader = new THREE.TextureLoader(); loader.crossOrigin = ''; loader.load('https://upload.wikimedia.org/wikipedia/commons/thumb/8/83/Equirectangular_projection_SW.jpg/640px-Equirectangular_projection_SW.jpg', function(texture) { var geometry = new THREE.SphereGeometry(180, 32, 32); var material = new THREE.MeshBasicMaterial({ map: texture, overdraw: 0.5 }); var mesh = new THREE.Mesh(geometry, material); group.add(mesh); }); // shadow var canvas = document.createElement('canvas'); canvas.width = 128; canvas.height = 128; var context = canvas.getContext('2d'); var gradient = context.createRadialGradient( canvas.width / 2, canvas.height / 2, 0, canvas.width / 2, canvas.height / 2, canvas.width / 2 ); gradient.addColorStop(0.1, '#000000'); gradient.addColorStop(1, '#000000'); context.fillStyle = gradient; context.fillRect(0, 0, canvas.width, canvas.height); var texture = new THREE.CanvasTexture(canvas); var geometry = new THREE.PlaneBufferGeometry(300, 300, 3, 3); var material = new THREE.MeshBasicMaterial({ map: texture, overdraw: 0.5 }); var mesh = new THREE.Mesh(geometry, material); mesh.position.y = -200; mesh.rotation.x = -Math.PI / 2; group.add(mesh); renderer = new THREE.WebGLRenderer({ antialias: false, alpha: true }); renderer.setPixelRatio(window.devicePixelRatio); renderer.setSize(window.innerWidth, window.innerHeight); //renderer.setClearColor(0x000000, 0); container.appendChild(renderer.domElement); stats = new Stats(); container.appendChild(stats.dom); document.addEventListener('mousemove', onDocumentMouseMove, false); // window.addEventListener('resize', onWindowResize, false); } function onWindowResize() { windowHalfX = window.innerWidth / 2; windowHalfY = window.innerHeight / 2; camera.aspect = window.innerWidth / window.innerHeight; camera.updateProjectionMatrix(); renderer.setSize(window.innerWidth, window.innerHeight); } function onDocumentMouseMove(event) { mouseX = (event.clientX - windowHalfX); mouseY = (event.clientY - windowHalfY); } // function animate() { requestAnimationFrame(animate); render(); stats.update(); } function render() { camera.position.x += (mouseX - camera.position.x) * 0.08; camera.position.y += (-mouseY - camera.position.y) * 0.08; camera.lookAt(scene.position); group.rotation.y -= 0.003; renderer.render(scene, camera); } 

 body { color: #ffffff; font-family: 'Futura'; font-size: 20px; text-align: center; background-image: url(https://upload.wikimedia.org/wikipedia/commons/6/62/Starsinthesky.jpg); background-color: black; margin: 0px; overflow: hidden; } 

 <script src="https://threejs.org/build/three.js"></script> <script src="https://threejs.org/examples/js/renderers/Projector.js"></script> <script src="https://threejs.org/examples/js/libs/stats.min.js"></script> <div id="container"></div> 

three.js r86

Answer 3

有两种方法可以做到这一点

1）使用TextureLoader加载图像并将其设置为背景。 这将导致看起来可能不太现实的静态背景。

 var texture = new THREE.TextureLoader().load(
      "https://images.pexels.com/photos/110854/pexels-photo-110854.jpeg?auto=compress&cs=tinysrgb&dpr=2&h=650&w=940"
    );
   scene.background = texture;

2）使用skybox加载顶部，左侧，右侧底部，正面和背面的图像。 然后将它们设置在立方体或球体几何中

var urls = [
      "https://images.pexels.com/photos/110854/pexels-photo-110854.jpeg",
      "https://images.pexels.com/photos/110854/pexels-photo-110854.jpeg",
      "https://images.pexels.com/photos/110854/pexels-photo-110854.jpeg",
      "https://images.pexels.com/photos/110854/pexels-photo-110854.jpeg",
      "https://images.pexels.com/photos/110854/pexels-photo-110854.jpeg",
      "https://images.pexels.com/photos/110854/pexels-photo-110854.jpeg"
    ];

    var materialArray = [];
    for (var i = 0; i < 6; i++)
      materialArray.push(
        new THREE.MeshBasicMaterial({
          map: new THREE.TextureLoader().load(urls[i]),
          side: THREE.BackSide
        })
      );

    var skyGeometry = new THREE.SphereGeometry(400, 32, 32);
    var skyMaterial = new THREE.MeshFaceMaterial(materialArray);
    var skybox = new THREE.Mesh(skyGeometry, skyMaterial);
    scene.add(skybox);

这将在背面提供一个具有图像纹理的球体。 只需将THREE.SphereGeometry替换为THREE.CubeGeometry ，就可以模拟envMap。