Last active
October 11, 2019 19:10
-
-
Save plugnburn/5371798326cb894e3ef17e33f1646c65 to your computer and use it in GitHub Desktop.
STL2SCAD.js - Optimizing decompiler of a binary STL into the OpenSCAD source
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| /** | |
| * Optimizing decompiler of a binary STL into the OpenSCAD polyhedron module | |
| * @license Unlicense | |
| * | |
| * @param {ArrayBuffer} stl STL file contents (binary flavor) | |
| * @param {string} optional custom name for OpenSCAD object (if none passed then 'object{NumTriangles}' will be used) | |
| * @returns {string} ready OpenSCAD script | |
| */ | |
| function STL2SCAD(stl, optModName = null) { | |
| var totalTriangles = new Uint32Array(stl.slice(80, 84))[0], //triangle amount is LE uint at byte 80 | |
| cVD = new Uint8Array(stl.slice(84)), //points should start from byte 84 | |
| i, k, l = cVD.length, p, pKey, vertices = [], triangles = [], | |
| modName = optModName || ('object' + totalTriangles), | |
| embrace = a => '[' + a.join(', ') + ']', | |
| reslice = (i, k) => new Float32Array(cVD.slice(i+k+12, i+k+16).buffer)[0].toFixed(5) + 0, | |
| vertexCache = {}, triangle | |
| //trim the garbage | |
| if(l > totalTriangles * 50) | |
| l = totalTriangles * 50 | |
| for(i=0;i<l;i+=50) { //two loops to skip all unused bytes | |
| triangle = [] | |
| for(k=0;k<3;k++) { | |
| p = { | |
| x: reslice(i, 12*k), | |
| y: reslice(i, 12*k + 4), | |
| z: reslice(i, 12*k + 8) | |
| } | |
| pKey = [p.x, p.y, p.z].join(':') | |
| if(!vertexCache[pKey]) { | |
| vertices.push(embrace([p.x,p.y,p.z])) | |
| vertexCache[pKey] = vertices.length - 1 | |
| } | |
| triangle.push(vertexCache[pKey]) | |
| } | |
| triangles.push(embrace([triangle[0], triangle[2], triangle[1]])) | |
| } | |
| return 'module ' + modName + ' () {\n\tpolyhedron(\n\t\tpoints=' | |
| + embrace(vertices) + ',\n\t\tfaces=' | |
| + embrace(triangles) + '\n\t);\n}\n' + modName + '();' | |
| } | |
| if(module) { | |
| module.exports = STL2SCAD | |
| if(typeof require !== 'undefined' && require.main === module) { | |
| const fs = require('fs') | |
| let stlContents = fs.readFileSync(process.argv[2]) | |
| console.log(STL2SCAD(stlContents.buffer)) | |
| } | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment