我为我的应用程序重新创建了一个包模型,并将其作为 .obj 导出到 ThreeJs:
我为模型几何中的每个面分配了不同的颜色,如下所示:
var geometry = new THREE.Geometry().fromBufferGeometry( bagMesh.children[0].geometry );
for (var i = 0; i < geometry.faces.length; i ++ ) {
var face = geometry.faces[i];
// 7 & 8 = front side
// can we flip its normal?
if(i === 7 || i === 8) {
face.color.setHex( 0xff0000 );
} else {
face.color.setHex( Math.random() * 0xffffff );
}
}
geometry.translate( 0, -1, 0.75);
mesh = new THREE.Mesh( geometry, new THREE.MeshBasicMaterial({ vertexColors: THREE.FaceColors, side: THREE.DoubleSide }) );
scene.add(mesh);
我已经在面阵列的索引 7 和 8 处识别了正面的面,并将它们变成红色。
问题是当我查看包包内部时也可以看到这种颜色:
我意识到这是因为我已将对象设置为
THREE.DoubleSide
但是如果我把它改成 THREE.FrontSide
那么侧面只能部分可见。所以我的问题是如何为每一侧(所有 11 个,也计算内部)分配不同的独特颜色,而该颜色不会出现在相对的两侧?
我试图通过只使用颜色而不是将图像映射到它来使事情保持简单,这就是我最终想要达到的。
注意 - 我之前的模型通过将每一侧视为单独的网格来解决这个问题,但这会导致其他问题,如 z 隐藏和闪烁问题。
谢谢
编辑
@WestLangley 我已经设置了一个 fiddle 来演示您在评论中添加的内容。假设我做对了,它没有达到预期的效果:
(function onLoad() {
var canvasElement;
var width, height;
var scene, camera;
var renderer;
var controls;
var pivot;
var bagMesh;
var planeMesh;
const objLoader = new THREE.OBJLoader2();
const fileLoader = new THREE.FileLoader();
init();
function init() {
container = document.getElementById('container');
initScene();
addGridHelper();
addCamera();
addLighting();
addRenderer();
addOrbitControls();
loadPlaneObj();
// Logic
var update = function() {};
// Draw scene
var render = function() {
renderer.render(scene, camera);
};
// Run game logic (update, render, repeat)
var gameLoop = function() {
requestAnimationFrame(gameLoop);
update();
render();
};
gameLoop();
}
/**** Basic Scene Setup ****/
function initScene() {
scene = new THREE.Scene();
scene.background = new THREE.Color(0xd3d3d3);
var axis = new THREE.AxesHelper();
scene.add(axis);
}
function addCamera() {
camera = new THREE.PerspectiveCamera(70, window.innerWidth / window.innerHeight, 1, 1000);
camera.position.set(3,3,3);
scene.add(camera);
}
function addGridHelper() {
var planeGeometry = new THREE.PlaneGeometry(2000, 2000);
planeGeometry.rotateX(-Math.PI / 2);
var planeMaterial = new THREE.ShadowMaterial({
opacity: 0.2
});
var plane = new THREE.Mesh(planeGeometry, planeMaterial);
plane.position.y = -200;
plane.receiveShadow = true;
scene.add(plane);
var helper = new THREE.GridHelper(2000, 100);
helper.material.opacity = 0.25;
helper.material.transparent = true;
scene.add(helper);
var axis = new THREE.AxesHelper();
scene.add(axis);
}
// *********** Lighting settings **********************
function addLighting() {
var light = new THREE.HemisphereLight(0xffffff, 0xffffff, 1);
scene.add(light);
}
// ************** Material settings **************
function setMaterial(materialName) {
// get the object from the scene
var bagMesh = scene.getObjectByName('bag');
var material;
if (!materialName) {
materialName = materials.material;
}
if (bagMesh) {
var colour = parseInt(materials.colour);
switch (materialName) {
case 'MeshBasicMaterial':
material = new THREE.MeshBasicMaterial({
color: colour
});
break;
case 'MeshDepthMaterial':
material = new THREE.MeshDepthMaterial();
break;
case 'MeshLambertMaterial':
material = new THREE.MeshLambertMaterial({
color: colour
});
break;
case 'MeshNormalMaterial':
material = new THREE.MeshNormalMaterial();
break;
case 'MeshPhongMaterial':
material = new THREE.MeshPhongMaterial({
color: colour
});
break;
case 'MeshPhysicalMaterial':
material = new THREE.MeshPhysicalMaterial({
color: colour
});
break;
case 'MeshStandardMaterial':
material = new THREE.MeshStandardMaterial({
color: colour
});
break;
case 'MeshToonMaterial':
material = new THREE.MeshToonMaterial({
color: colour
});
break;
}
bagMesh.children.forEach(function(c) {
c.material = material;
});
}
}
function setMaterialColour(colour) {
materials.colour = colour;
setMaterial(null);
}
// ************** End of materials ***************
function addRenderer() {
renderer = new THREE.WebGLRenderer({
antialias: true
});
renderer.setPixelRatio(window.devicePixelRatio);
renderer.setSize(window.innerWidth, window.innerHeight);
renderer.shadowMap.enabled = true;
container.appendChild(renderer.domElement);
}
function addOrbitControls() {
var controls = new THREE.OrbitControls(camera, renderer.domElement);
}
function addPivot() {
var cubeGeo = new THREE.BoxBufferGeometry(5, 5, 5);
var cubeMat = new THREE.MeshBasicMaterial();
pivot = new THREE.Mesh(cubeGeo, cubeMat);
bagMesh.position.x -= 15;
bagMesh.position.z -= 55;
pivot.add(bagMesh);
pivot.add(handle);
scene.add(pivot);
}
function loadPlaneObj() {
loadObj('Plane', 'https://rawgit.com/Katana24/threejs-experimentation/master/models/Plane.obj', 'https://rawgit.com/Katana24/threejs-experimentation/master/models/Plane.mtl', addPlaneToSceneSOAnswer);
}
function loadObj(objName, objUrl, mtlUrl, onLoadFunc) {
var onLoadMtl = function(materials) {
objLoader.setModelName(objName);
objLoader.setMaterials(materials);
fileLoader.setPath('');
fileLoader.setResponseType('arraybuffer');
fileLoader.load(objUrl,
function(onLoadContent) {
var mesh = objLoader.parse(onLoadContent);
onLoadFunc(mesh);
},
function(inProgress) {},
function(error) {
throw new Error('Couldnt load the model: ', error);
});
};
objLoader.loadMtl(mtlUrl, objName+'.mtl', onLoadMtl);
}
function addPlaneToSceneSOAnswer(mesh) {
var frontMaterial = new THREE.MeshBasicMaterial( { color : 0xff0000, side: THREE.FrontSide } );
var backMaterial = new THREE.MeshBasicMaterial( { color : 0x00ff00, side: THREE.BackSide } );
var geometry = new THREE.Geometry().fromBufferGeometry( mesh.children[0].geometry );
var length = geometry.faces.length;
geometry.faces.splice(14, 1);
for (var i = 0; i < geometry.faces.length; i ++ ) {
var face = geometry.faces[i];
face.color.setHex(Math.random() * 0xffffff);
}
mesh = new THREE.Mesh( geometry, new THREE.MeshBasicMaterial({ vertexColors: THREE.FaceColors, side: THREE.DoubleSide }) );
mesh.material.side = THREE.FrontSide;
var mesh2 = new THREE.Mesh( geometry, mesh.material.clone() );
mesh2.material.side = THREE.BackSide;
// mesh2.material.vertexColors = THREE.NoColors;
mesh2.material.vertexColors = [new THREE.Color(0xff0000), new THREE.Color(0x00ff00), new THREE.Color(0x0000ff)];
mesh.add( mesh2 );
scene.add(mesh);
}
})();
body {
background: transparent;
padding: 0;
margin: 0;
font-family: sans-serif;
}
#canvas {
margin: 10px auto;
width: 800px;
height: 350px;
margin-top: -44px;
}
<body>
<div id="container"></div>
<script src="https://threejs.org/build/three.js"></script>
<script src="https://threejs.org/examples/js/libs/dat.gui.min.js"></script>
<script src="https://threejs.org/examples/js/controls/OrbitControls.js"></script>
<script src="https://threejs.org/examples/js/loaders/MTLLoader.js"></script>
<script src="https://rawgit.com/mrdoob/three.js/dev/examples/js/loaders/LoaderSupport.js"></script>
<script src="https://rawgit.com/mrdoob/three.js/dev/examples/js/loaders/OBJLoader2.js"></script>
</body>
我在这里缺少什么?
最佳答案
我遵循了唐关于不同 Material 的建议,但并不完全明白他的意思。
我检查了这个 question其中详细设置materialIndex
.我调查了这意味着什么,这意味着当您通过 geometry
时和一个数组 materials
到这样的网格:
mesh = new THREE.Mesh( geometry, [frontMaterial, backMaterial, otherMaterial] );
然后该面将获得分配给它的 Material (frontMaterial,因为它位于位置 0)。
回到我最初的问题,我决定简化(暂时),看看我是否可以将我想要的应用到从 Blender 导出的平面网格上。
添加到 3JS 中时,平面有两个面。我发现我可以翻转每个面或为每个面分配不同的 Material ,但我需要复制面以实现这一点:
function addMeshTwoToScene() {
var frontMaterial = new THREE.MeshBasicMaterial( { color : 0xff0000, side: THREE.FrontSide } );
var backMaterial = new THREE.MeshBasicMaterial( { color : 0x00ff00, side: THREE.BackSide } );
var geometry = new THREE.Geometry().fromBufferGeometry( planeMesh.children[0].geometry );
// Duplicates the face
var length = geometry.faces.length;
for (var i = 0; i < length; i++ ) {
var face = geometry.faces[i];
var newFace = Object.assign({}, face);
geometry.faces.push(newFace);
}
for (var i = 0; i < geometry.faces.length; i ++ ) {
var face = geometry.faces[i];
if(i === 0 || i === 3) {
face.materialIndex = 0;
} else {
face.materialIndex = 1;
}
}
var mesh = new THREE.Mesh( geometry, [frontMaterial, backMaterial] );
scene.add(mesh);
}
这导致以下结果:
我不打算将此标记为已接受的答案,因为我仍然需要将其应用于问题中更复杂的模型,而且我认为还有更好的方法可以做到这一点,例如将特定顶点翻转到其他顶点值(value)。
关于three.js - 向这个 obj 的每一侧添加不同的颜色,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/48177470/