如何在 Three.js 中改变面部颜色 [英] How to change face color in Three.js

问题描述

我正在尝试更改网格单个面上的颜色.这是在 WebGL 上下文中.我可以更改整个网格颜色，而不是单个 Face.相关代码如下:

//更新 Per Lee！var 相机 = _this.camera;var 投影仪 = new THREE.Projector();var vector = new THREE.Vector3( ( event.clientX/window.innerWidth ) * 2 - 1, - ( event.clientY/window.innerHeight ) * 2 + 1, 0.5 );投影仪.unprojectVector(矢量，相机)；var ray = new THREE.Ray(camera.position, vector.subSelf(camera.position).normalize());var intersects = ray.intersectObjects( kage.scene.children );if ( intersects.length > 0 ) {脸=相交[0].脸；var faceIndices = ['a', 'b', 'c', 'd'];var numberOfSides = (face instanceof THREE.Face3) ?3 : 4;//为当前面的每个顶点分配颜色for( var j = 0; j 

我还初始化了对象，在本例中是一个 Cube，如下所示:

//这种材质使网格使用指定给顶点的颜色var material = new THREE.MeshBasicMaterial({颜色:0xf0f0f0，底纹:THREE.FlatShading，顶点颜色:THREE.VertexColors});var directionalLight = new THREE.DirectionalLight(0xEEEEEE);directionalLight.position.set(10, 1, 1).normalize();kage.scene.add(定向光)；var cube = new THREE.Mesh(new THREE.CubeGeometry(300, 300, 300,1,1,1), material);立方体动态 = 真；kage.scene.add(cube);

改变材质使立方体变成白色，而不管光的颜色如何.交集逻辑仍然有效，这意味着我选择了正确的人脸，但可惜颜色没有改变.

我是 Stackoverflow 的新手 [问一个问题，所以希望我的编辑不会令人困惑]

解决方案

• 将库更新到 r53.
• 添加 vertexColors: THREE.FaceColors材料.

• 最后使用face.color.setRGB(Math.random(),Math.random(), Math.random()).

  现在不需要遍历4个循环THREE.Face4 的边 (a,b,c,d) 或 3 个边 (a,b,c)THREE.Face3.

  这适用于 WebGL 和 Canvas 渲染.

示例

three.js r53

I am attempting to change the color on a single face of a mesh. This is in a WebGL context. I can change the entire mesh color, just not a single Face. Relevant code below:

// Updated Per Lee!

var camera = _this.camera;      
var projector = new THREE.Projector();
var vector = new THREE.Vector3( ( event.clientX / window.innerWidth ) * 2 - 1,                                  - ( event.clientY / window.innerHeight ) * 2 + 1, 0.5 );
projector.unprojectVector( vector, camera );

var ray = new THREE.Ray( camera.position, vector.subSelf( camera.position ).normalize() );
var intersects = ray.intersectObjects( kage.scene.children );

if ( intersects.length > 0 ) {
    face = intersects[0].face;
    var faceIndices = ['a', 'b', 'c', 'd'];         
    var numberOfSides = ( face instanceof THREE.Face3 ) ? 3 : 4;
    // assign color to each vertex of current face
    for( var j = 0; j < numberOfSides; j++ )  {
        var vertexIndex = face[ faceIndices[ j ] ];
    // initialize color variable
    var color = new THREE.Color( 0xffffff );
    color.setRGB( Math.random(), 0, 0 );
    face.vertexColors[ j ] = color;
    }
}

I also initialize the object, in this case a Cube as follows:

// this material causes a mesh to use colors assigned to vertices
var material = new THREE.MeshBasicMaterial( { 
    color: 0xf0f0f0, 
    shading: THREE.FlatShading,
    vertexColors: THREE.VertexColors 
});

var directionalLight = new THREE.DirectionalLight(0xEEEEEE);
directionalLight.position.set(10, 1, 1).normalize();
kage.scene.add(directionalLight);

var cube = new THREE.Mesh(new THREE.CubeGeometry(300, 300, 300,1,1,1), material);
cube.dynamic = true;
kage.scene.add(cube);

Changing the material makes the cube white regardless of the light color. The intersection logic still works, meaning i select the correct face, but alas the color does not change.

I'm new to Stackoverflow [well asking a question that is, so hopefully my edits are not confusing]

解决方案

• Update library to r53.
• Add vertexColors: THREE.FaceColors in material.

• And finally use face.color.setRGB( Math.random(), Math.random(), Math.random()).

  Now no need to traverse loop for 4 sides (a,b,c,d) for THREE.Face4 or 3 sides (a,b,c) for THREE.Face3.

  This works in both WebGL and Canvas rendering.

Example

three.js r53

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