如何从GLSL着色器替换的Three.js几何体中导出OBJ？ [英] How Do I Export OBJ From Three.js geometry that is being displaced by GLSL shader?

问题描述

我尝试使用我在Stack Overflow上找到的以下代码从Three.js场景中的几何体导出OBJ。 GLSL着色器正在替换几何体，因此顶点的位移似乎不会与几何体一起导出。当我将OBJ导入Blender时，我只得到没有移位的平面。您可以在 http://kineticvideo.co

I attempted to use the following code I found on Stack Overflow to export an OBJ from geometry in a Three.js scene. The geometry is being displaced by a GLSL shader so the displacement of vertices doesn't seem to export with the geometry. When I import the OBJ into Blender I only get the flat plane that is not displaced. You can inspect a working version of the displacement at http://kineticvideo.co

如何在使用GLSL着色器替换几何体时导出OBJ？请帮忙。我的印象是顶点的位移实际上会在Three.js几何体中实时更新，但是看起来即使我设置了geometry.verticesNeedUpdate = true;位移实际上发生在网格而不是几何体中。

How do I export an OBJ while using a GLSL shader to displace the geometry? Please help. I was under the impression the displacement of the vertices would actually be updated in the Three.js geometry in real time, but instead it seems like even though I set geometry.verticesNeedUpdate = true; the displacement is actually happening in the mesh and not the geometry.

如果是这样，我如何使用网格而不是几何体导出OBJ？

If so, how do I export an OBJ using from the mesh and not the geometry?

来自Three.js的代码片段，用于声明几何体和顶点着色器：

A code snippet from the Three.js that declares the geometry and vertex shader:

videoMaterial = new THREE.ShaderMaterial( {
    uniforms: {
        "tDiffuse": { type: "t", value: texture },
        "multiplier":  { type: "f", value: 66.6 },
        "displace":  { type: "f", value: 33.3 },
        "opacity":  { type: "f", value: 1.0 },
        "originX":  { type: "f", value: 0.0 },
        "originY":  { type: "f", value: 0.0 },
        "originZ":  { type: "f", value: -2000.0 }
    },

    vertexShader: RuttEtraShader.vertexShader,
    fragmentShader: RuttEtraShader.fragmentShader,
    depthWrite: true,
    depthTest: true,
    wireframe: false, 
    transparent: true,
    overdraw: false

});
videoMaterial.renderToScreen = true;
videoMaterial.wireframe = true;
geometry = new THREE.PlaneGeometry(720, 360, 720, 360);
geometry.overdraw = false;
geometry.dynamic = true;
geometry.verticesNeedUpdate = true;

mesh = new THREE.Mesh( geometry, videoMaterial );

这是我用来导出几何体但不是位移的函数：

This is the function I used which does export the geometry, but not the displacement:

THREE.saveGeometryToObj = function (geometry) {
var s = '';
for (i = 0; i < geometry.vertices.length; i++) {
    s+= 'v '+(geometry.vertices[i].x) + ' ' +
    geometry.vertices[i].y + ' '+
    geometry.vertices[i].z + '\n';
}

for (i = 0; i < geometry.faces.length; i++) {

    s+= 'f '+ (geometry.faces[i].a+1) + ' ' +
    (geometry.faces[i].b+1) + ' '+
    (geometry.faces[i].c+1);

    if (geometry.faces[i].d !== undefined) {
        s+= ' '+ (geometry.faces[i].d+1);
    }
    s+= '\n';
}

return s;
console.log(s);
}

推荐答案

我的错误是谷歌搜索，而不是在Three.js回购中运行grep。那里有各种各样的功能，其中两个是THREE.STLExporter和THREE.OBJExporter。

My mistake was googling this, rather than running a grep in the Three.js repo. There all sorts of functions in there to use, two of them being THREE.STLExporter and THREE.OBJExporter.

THREE.STLExporter似乎是两者中更强大的，允许您遍历场景并导出场景中的网格。您还可以导出单个网格。虽然我没有获得OBJ，但STL对我的目的是好的。

THREE.STLExporter seems to be the more robust of the two, allowing you to traverse a scene and export meshes in the scene. You can also export a singular mesh. While I don't get an OBJ, a STL is fine for my purposes.

var exportSTL = new THREE.STLExporter;
exportSTL.exportMesh(mesh);

但这只能部分回答原始问题，因为移位的网格仍然无法导出。我得到的只是原始飞机。

But this only partially answers the the original question, because well the displaced mesh still doesn't export. All I get is the original plane.

这篇关于如何从GLSL着色器替换的Three.js几何体中导出OBJ？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！