MeshNormalMaterial 不适用于three.js 自定义几何图形:几何图形呈现为黑色 [英] MeshNormalMaterial not working on a three.js custom geometry: the geometry renders as black

问题描述

我试图通过声明其向量和面来使用three.js手动构建一个立方体；我可以使用下面的代码来做到这一点，但是，材料似乎没有按预期工作，而是立方体呈现为纯黑色.

I am trying to construct a cube manually using three.js by declaring its vectors and faces; I am able to do it using the code below, however, the material does not seem to be working as expected, instead the cube is rendering in a solid black color.

var geom = new THREE.Geometry(); 
var v1 = new THREE.Vector3( -1,  1, 0.1 ),
    v2 = new THREE.Vector3(  1,  1, 0.1 ),
    v3 = new THREE.Vector3(  1, -1, 0.1 ),
    v4 = new THREE.Vector3( -1, -1, 0.1 ),
    v5 = new THREE.Vector3( -1,  1, 2   ),
    v6 = new THREE.Vector3(  1,  1, 2   ),
    v7 = new THREE.Vector3(  1, -1, 2   ),
    v8 = new THREE.Vector3( -1, -1, 2   );

geom.vertices.push(v1,v2,v3,v4,v5,v6,v7,v8);

geom.faces.push(
  new THREE.Face3(0,1,3),
  new THREE.Face3(1,2,3),
  new THREE.Face3(4,5,7),
  new THREE.Face3(5,6,7),
  new THREE.Face3(1,4,5),
  new THREE.Face3(0,1,4),
  new THREE.Face3(2,3,7),
  new THREE.Face3(2,6,7),
  new THREE.Face3(0,3,7),
  new THREE.Face3(0,4,7),
  new THREE.Face3(1,2,5),
  new THREE.Face3(2,5,6)  
);

var mat = new THREE.MeshNormalMaterial();
mat.side = THREE.DoubleSide;
var cube = new THREE.Mesh( geom, mat);
scene.add(cube);

如果我使用下面的代码正常渲染多维数据集，则多维数据集会按预期渲染.

If I render the cube normally, using the code that follows, the cube renders as expected.

cube = new THREE.Mesh(new THREE.CubeGeometry(2, 2, 2), new THREE.MeshNormalMaterial());
scene.add(cube);

推荐答案

您尚未指定顶点法线.对于一些快速的事情，计算面法线，如下所示:

You haven't specified vertex normals. For something quick, compute face normals, like so:

geom.computeFaceNormals();

但是您应该学习如何在自定义几何体中设置顶点法线.

but you should learn how to set vertex normals in your custom geometry.

此外，面缠绕顺序"应该是逆时针的.你并没有一直这样做.

Also, face "winding order" should be counter-clockwise. You are not consistently doing that.

如果你正确定义了面，你可以删除side = THREE.DoubleSide.

If you define faces correctly, you can remove side = THREE.DoubleSide.

three.js r.90

three.js r.90

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