automatically center model in viewer - cc #8

js/viewer/model.js

@@ -1,16 +1,44 @@
 require('../vendor/STLLoader');
 
+// https://github.com/mrdoob/three.js/issues/447#issuecomment-55111928
+var getCentroid = function(boundingBox) {
+  var centroid = boundingBox.min.clone();
+  centroid.add(boundingBox.max);
+  centroid.divideScalar(2);
+
+  return centroid;
+};
+
+var getBoxSize = function(boundingBox) {
+  var sizeVector = boundingBox.max.clone();
+  sizeVector.sub(boundingBox.min);
+  return sizeVector.length();
+};
+
+var placeInCenter = function(mesh) {
+  mesh.geometry.computeBoundingBox();
+
+  var offset = new THREE.Vector3(0, -1, -1);
+  var centroid = getCentroid(mesh.geometry.boundingBox);
+  offset.add(centroid);
+  mesh.position.copy(offset);
+
+  var boxSize = getBoxSize(mesh.geometry.boundingBox);
+  var sizeScalar = 150 / boxSize;
+  mesh.scale.set( sizeScalar, sizeScalar, sizeScalar );
+
+  mesh.rotation.set( - Math.PI / 2, 0, 0 );
+};
+
+
 var material = new THREE.MeshPhongMaterial( { ambient: 0x555555, color: 0xAAAAAA, specular: 0x111111, shininess: 200 } );
 
 var load = function(callback) {
   var loader = new THREE.STLLoader();
   loader.addEventListener('load', function(event) {
     var geometry = event.content;
     var mesh = new THREE.Mesh(geometry, material);
-
-    mesh.position.set( 0, - 0.37, - 0.6 );
-    mesh.rotation.set( - Math.PI / 2, 0, 0 );
-    mesh.scale.set( 2, 2, 2 );
+    placeInCenter(mesh);
 
     mesh.castShadow = true;
     mesh.receiveShadow = true;