Added test

specs/data/box-incorrect-winding-order/box-incorrect-winding-order.mtl

@@ -0,0 +1,10 @@
+# Blender MTL File: 'None'
+# Material Count: 1
+
+newmtl None
+Ns 0
+Ka 0.000000 0.000000 0.000000
+Kd 0.8 0.8 0.8
+Ks 0.8 0.8 0.8
+d 1
+illum 2

specs/data/box-incorrect-winding-order/box-incorrect-winding-order.obj

@@ -0,0 +1,32 @@
+# Blender v2.78 (sub 0) OBJ File: ''
+# www.blender.org
+mtllib box-incorrect-winding-order.mtl
+o Cube_Cube.001
+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
+vn -1.0000 0.0000 0.0000
+vn 0.0000 0.0000 -1.0000
+vn 1.0000 0.0000 0.0000
+vn 0.0000 0.0000 1.0000
+vn 0.0000 -1.0000 0.0000
+vn 0.0000 1.0000 0.0000
+usemtl None
+s off
+f 1//1 3//1 2//1
+f 4//2 7//2 3//2
+f 8//3 5//3 7//3
+f 6//4 1//4 5//4
+f 7//5 1//5 3//5
+f 4//6 6//6 8//6
+f 2//1 4//1 3//1
+f 4//2 8//2 7//2
+f 8//3 6//3 5//3
+f 6//4 2//4 1//4
+f 7//5 5//5 1//5
+f 4//6 2//6 6//6

specs/lib/loadObjSpec.js

@@ -46,6 +46,7 @@ const objMissingAttributesPath = 'specs/data/box-missing-attributes/box-missing-
 const objIncompletePositionsPath = 'specs/data/box-incomplete-attributes/box-incomplete-positions.obj';
 const objIncompleteNormalsPath = 'specs/data/box-incomplete-attributes/box-incomplete-normals.obj';
 const objIncompleteUvsPath = 'specs/data/box-incomplete-attributes/box-incomplete-uvs.obj';
+const objIncorrectWindingOrderPath = 'specs/data/box-incorrect-winding-order/box-incorrect-winding-order.obj';
 const objInvalidPath = 'invalid.obj';
 
 function getMeshes(data) {
@@ -511,6 +512,29 @@ describe('loadObj', () => {
         expect(primitive.uvs.length).toBe(0);
     });
 
+    async function loadAndGetIndices(objPath, options) {
+        const data = await loadObj(objPath, options);
+        const primitive = getPrimitives(data)[0];
+        const indices = primitive.indices;
+        return new Uint16Array(indices.toUint16Buffer().buffer);
+    }
+
+    it('applies triangle winding order sanitization', async () => {
+        options.triangleWindingOrderSanitization = false;
+        const indicesIncorrect = await loadAndGetIndices(objIncorrectWindingOrderPath, options);
+
+        options.triangleWindingOrderSanitization = true;
+        const indicesCorrect = await loadAndGetIndices(objIncorrectWindingOrderPath, options);
+
+        expect(indicesIncorrect[0]).toBe(0);
+        expect(indicesIncorrect[2]).toBe(2);
+        expect(indicesIncorrect[1]).toBe(1);
+
+        expect(indicesCorrect[0]).toBe(0);
+        expect(indicesCorrect[2]).toBe(1);
+        expect(indicesCorrect[1]).toBe(2);
+    });
+
     it('throws when position index is out of bounds', async () => {
         let thrownError;
         try {