stl reader and url loader

web/app/3d/io.js

@@ -0,0 +1,23 @@
+import {ParseStl} from './stl/stl-reader'
+
+export function LoadSTLFromURL(url, solidsConsumer) {
+  const xhr = new XMLHttpRequest();
+  xhr.onreadystatechange = function(){
+    if (this.readyState == 4){
+      //console.log(this.response, typeof this.response);
+      if (this.status == 200) {
+        const reader = new FileReader();
+        reader.addEventListener("loadend", () => {
+          let solids = ParseStl(reader.result);
+          solidsConsumer(solids)
+        });
+        reader.readAsArrayBuffer(this.response);
+      } else {
+        solidsConsumer(null, this.status);
+      }
+    } 
+  };
+  xhr.open('GET', url);
+  xhr.responseType = 'blob';
+  xhr.send();
+}

web/app/3d/stl/stl-ascii-reader.js

@@ -1,15 +1,15 @@
+import {StlSolid, StlFace} from './stl-data-structure'
+
 export function parse(buf) {
 
-  var solid = {
-    name: null,
-    faces: []    
-  };
-  var solids = [];
-  var triangle = [];
-  var normal = null;  
-  var reader = new LinesReader(buf);
+  let solid = new StlSolid('');
+  let face = new StlFace(null);
+  let solids = [];
+  let reader = new LinesReader(buf);
+  let lineNumber = 0;
   while (reader.hasNextLine()) {
-    let line = reader.nextLine();  
+    let line = reader.nextLine();
+    lineNumber ++;
     var parts = line
       .trim()
       .split(' ')
@@ -18,10 +18,7 @@ export function parse(buf) {
       });
     switch(parts[0]) {
       case 'solid':
-        solid = {
-          name: parts.slice(1).join(' '),
-          faces: []
-        };
+        solid = new StlSolid(parts.slice(1).join(' '));
         break;
       case 'endsolid':
         solids.push(solid);
@@ -29,22 +26,22 @@ export function parse(buf) {
       case 'facet':
         var noramlParts = parts.slice(2);
         if (noramlParts.length == 3) {
-          normal = noramlParts.map(Number);
+          face.normal = noramlParts.map(Number);
+        } else {
+          console.warn('bad normal definition at line ' + lineNumber);
         }
         break;
       case 'vertex':
-        var position = parts.slice(1).map(Number);
-        triangle.push(position);
+        const position = parts.slice(1).map(Number);
+        face.vertices.push(position);
         break;
       case 'endfacet':
-        if (triangle.length == 3) {
-          solid.faces.push({
-            vertices: triangle,
-            normal: normal 
-          });
+        if (face.normal != null && face.vertices.length == 3) {
+          solid.faces.push(face);
+        } else {
+          console.warn('bad stl face at line ' + lineNumber);
         }
-        triangle = [];
-        normal = null;
+        face = new StlFace(null);
       default:
       // skip
     }

web/app/3d/stl/stl-data-structure.js

@@ -0,0 +1,9 @@
+export function StlSolid(name) {
+  this.name = name;
+  this.faces = [];
+}
+
+export function StlFace(normal) {
+  this.normal = normal;
+  this.vertices = [];
+}

web/app/3d/stl/stl-reader.js

@@ -5,13 +5,18 @@ export function ParseStl(buf) {
   if(typeof buf === 'string') {
     return ParseASCII(buf);
   }
+  
+  // The other way is to check if file starts with 'solid' then it's ascii
+  // WIKI: A binary STL file has an 80-character header (which is generally ignored, but should never begin with "solid" 
+  // because that will lead most software to assume that this is an ASCII STL file
 
-  //var triangleCount = buf.readUInt32LE(80);
-  //var expectedSize = 80 + 4 + triangleCount * ((4 * 3) * 4 + 2);
-  //
-  //if(expectedSize === buf.length) {
-  //  return parseBinary(buf);
-  //}
+  const dataView = new DataView(buf);
+  const triangleCount = dataView.getUint32(80, true);
+  const expectedSize = 80 + 4 + triangleCount * ((4 * 3) * 4 + 2);
+  
+  if(expectedSize === buf.byteLength) {
+    return [ParseBinary(dataView)];
+  }
 
   return ParseASCII(buf);
 }