Merge pull request #5990 from tsone/obj-mtl-bump-map-support

MTLLoader:  Support for loading bump maps

examples/js/loaders/MTLLoader.js

@@ -340,6 +340,19 @@ THREE.MTLLoader.MaterialCreator.prototype = {
 
 					break;
 
+				case 'map_bump':
+				case 'bump':
+
+					// Bump texture map
+
+					if ( params[ 'bumpMap' ] ) break; // Avoid loading twice.
+
+					params[ 'bumpMap' ] = this.loadTexture( this.baseUrl + value );
+					params[ 'bumpMap' ].wrapS = this.wrap;
+					params[ 'bumpMap' ].wrapT = this.wrap;
+
+					break;
+
 				default:
 					break;