Normalize normals

lib/loadObj.js

@@ -447,9 +447,15 @@ function loadObj(objPath, options) {
             positions.push(parseFloat(result[2]));
             positions.push(parseFloat(result[3]));
         } else if ((result = normalPattern.exec(line) ) !== null) {
-            normals.push(parseFloat(result[1]));
-            normals.push(parseFloat(result[2]));
-            normals.push(parseFloat(result[3]));
+            var normal = Cartesian3.fromElements(parseFloat(result[1]), parseFloat(result[2]), parseFloat(result[3]), scratchNormal);
+            if (Cartesian3.equals(normal, Cartesian3.ZERO)) {
+                Cartesian3.clone(Cartesian3.UNIT_Z, normal);
+            } else {
+                Cartesian3.normalize(normal, normal);
+            }
+            normals.push(normal.x);
+            normals.push(normal.y);
+            normals.push(normal.z);
         } else if ((result = uvPattern.exec(line)) !== null) {
             uvs.push(parseFloat(result[1]));
             uvs.push(1.0 - parseFloat(result[2])); // Flip y so 0.0 is the bottom of the image

specs/data/box-unnormalized/box-unnormalized.mtl

@@ -0,0 +1,12 @@
+# Blender MTL File: 'None'
+# Material Count: 1
+
+newmtl Material
+Ns 96.078431
+Ka 0.100000 0.000000 0.000000
+Kd 0.640000 0.640000 0.640000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.100000
+Ni 1.000000
+d 1.000000
+illum 2

specs/data/box-unnormalized/box-unnormalized.obj

@@ -0,0 +1,46 @@
+# Blender v2.78 (sub 0) OBJ File: ''
+# www.blender.org
+mtllib box-unnormalized.mtl
+o Cube
+v -1.000000 -1.000000 1.000000
+v -1.000000 1.000000 1.000000
+v -1.000000 -1.000000 -1.000000
+v -1.000000 1.000000 -1.000000
+v 1.000000 -1.000000 1.000000
+v 1.000000 1.000000 1.000000
+v 1.000000 -1.000000 -1.000000
+v 1.000000 1.000000 -1.000000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 0.0000
+vt 0.0000 1.0000
+vn 0.0000 0.0000 0.0000
+vn 0.0000 0.0000 0.5
+vn 1.0000 0.1000 0.0000
+vn 0.0000 0.0000 -0.9
+vn 0.0000 1.0000 0.0000
+vn 10.0000 -10.0000 5.0000
+usemtl Material
+s off
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3/5/2 4/6/2 8/7/2 7/8/2
+f 7/9/3 8/10/3 6/11/3 5/12/3
+f 5/13/4 6/14/4 2/15/4 1/16/4
+f 3/5/5 7/17/5 5/18/5 1/16/5
+f 8/19/6 4/6/6 2/15/6 6/20/6

specs/lib/loadObjSpec.js

@@ -4,6 +4,8 @@ var Promise = require('bluebird');
 var loadObj = require('../../lib/loadObj');
 var obj2gltf = require('../../lib/obj2gltf');
 
+var Cartesian3 = Cesium.Cartesian3;
+var CesiumMath = Cesium.Math;
 var clone = Cesium.clone;
 var RuntimeError = Cesium.RuntimeError;
 
@@ -33,6 +35,7 @@ var objMissingTexturePath = 'specs/data/box-missing-texture/box-missing-texture.
 var objSubdirectoriesPath = 'specs/data/box-subdirectories/box-textured.obj';
 var objInvalidContentsPath = 'specs/data/box/box.mtl';
 var objConcavePath = 'specs/data/concave/concave.obj';
+var objUnnormalizedPath = 'specs/data/box-unnormalized/box-unnormalized.obj';
 var objInvalidPath = 'invalid.obj';
 
 function getMeshes(data) {
@@ -107,6 +110,23 @@ describe('loadObj', function() {
             }), done).toResolve();
     });
 
+    it('normalizes normals', function(done) {
+        expect(loadObj(objUnnormalizedPath, options)
+            .then(function(data) {
+                var scratchNormal = new Cesium.Cartesian3();
+                var mesh = getMeshes(data)[0];
+                var normals = mesh.normals;
+                var normalsLength = normals.length / 3;
+                for (var i = 0; i < normalsLength; ++i) {
+                    var normalX = normals.get(i * 3);
+                    var normalY = normals.get(i * 3 + 1);
+                    var normalZ = normals.get(i * 3 + 2);
+                    var normal = Cartesian3.fromElements(normalX, normalY, normalZ, scratchNormal);
+                    expect(Cartesian3.magnitude(normal)).toEqualEpsilon(1.0, CesiumMath.EPSILON5);
+                }
+            }), done).toResolve();
+    });
+
     it('loads obj with uvs', function(done) {
         expect(loadObj(objUvsPath, options)
             .then(function(data) {