three.js - Three.js png纹理-Alpha渲染为白色而不是透明

Question

我正在创建一个多维数据集，并将6种不同的纹理应用于每个面。每个纹理都是一个.png文件，并包含透明部分。我还在立方体上应用了一种颜色-我想看到该颜色通过png透明。

问题:透明度呈现为白色，因此我看不到立方体的底色(如果删除png纹理，则呈现为正常)

如何使png透明度起作用？我尝试了一些 Material 设置，但没有一个使它透明。

用于创建多维数据集和 Material 的代码:

var geometry = new THREE.CubeGeometry(150, 200, 150, 2, 2, 2);
var materials = [];

// create textures array for all cube sides
for (var i = 1; i < 7; i++) {
   var img = new Image();
   img.src = 'img/s' + i + '.png';
   var tex = new THREE.Texture(img);
   img.tex = tex;

   img.onload = function () {
      this.tex.needsUpdate = true;
   };

   var mat = new THREE.MeshBasicMaterial({color: 0x00ff00, map: tex, transparent: true, overdraw: true });
   materials.push(mat);
}
cube = new THREE.Mesh(geometry, new THREE.MeshFaceMaterial(materials));
cube.position.y = 150;
scene.add(cube);

编辑:

下图显示了该问题-使用sendhanal解决方案时，左侧纹理现在可以正常显示-这是没有透明度的png图像-我在代码中设置了透明度

materialArray.push(new THREE.MeshBasicMaterial({ map: THREE.ImageUtils.loadTexture('img/s2.png'), transparent: true, opacity: 0.9, color: 0xFF0000 }));

正确的纹理也是png图像-仅它具有透明区域(所有呈现白色的应该是纯红色，因为它是透明的并且应该从立方体中获取颜色？)。如何使白色部分透明？

Answer 1

Material 的不透明度属性为您解决了问题。遵循示例代码片段:

var materialArray = [];
materialArray.push(new THREE.MeshBasicMaterial( { map: THREE.ImageUtils.loadTexture( 'images/xpos.png' ), transparent: true, opacity: 0.5, color: 0xFF0000 }));
materialArray.push(new THREE.MeshBasicMaterial( { map: THREE.ImageUtils.loadTexture( 'images/xneg.png' ), transparent: true, opacity: 0.5, color: 0xFF0000 }));
materialArray.push(new THREE.MeshBasicMaterial( { map: THREE.ImageUtils.loadTexture( 'images/ypos.png' ), transparent: true, opacity: 0.5, color: 0xFF0000 }));
materialArray.push(new THREE.MeshBasicMaterial( { map: THREE.ImageUtils.loadTexture( 'images/yneg.png' ), transparent: true, opacity: 0.5, color: 0xFF0000 }));
materialArray.push(new THREE.MeshBasicMaterial( { map: THREE.ImageUtils.loadTexture( 'images/zpos.png' ), transparent: true, opacity: 0.5, color: 0xFF0000 }));
materialArray.push(new THREE.MeshBasicMaterial( { map: THREE.ImageUtils.loadTexture( 'images/zneg.png' ), transparent: true, opacity: 0.5, color: 0xFF0000 }));
var MovingCubeMat = new THREE.MeshFaceMaterial(materialArray);
var MovingCubeGeom = new THREE.CubeGeometry( 50, 50, 50, 1, 1, 1, materialArray );
MovingCube = new THREE.Mesh( MovingCubeGeom, MovingCubeMat );
MovingCube.position.set(0, 25.1, 0);
scene.add( MovingCube );    

http://threejs.org/docs/#Reference/Materials/Material关键是将透明属性设置为true并将不透明度设置为0.5(例如)。
从@WestLangley(Three.js canvas render and transparency)的想法中添加第二个完全适合不透明的立方体

backCube = new THREE.Mesh( MovingCubeGeom, new THREE.MeshBasicMaterial( { color: 0xFF0000 }) );
backCube.position.set(0, 25.1, 0);
backCube.scale.set( 0.99, 0.99, 0.99 );
scene.add( backCube );