Can specify alpha offset angle (#8538)

This allows users to specify an offset angle for the alpha value. Can be used to set an initial view direction when the device orientation controls are called.

(Also ran it through whitespace checker)

examples/js/controls/DeviceOrientationControls.js

@@ -5,7 +5,7 @@
  * W3C Device Orientation control (http://w3c.github.io/deviceorientation/spec-source-orientation.html)
  */
 
-THREE.DeviceOrientationControls = function ( object ) {
+THREE.DeviceOrientationControls = function( object ) {
 
 	var scope = this;
 
@@ -17,13 +17,17 @@ THREE.DeviceOrientationControls = function ( object ) {
 	this.deviceOrientation = {};
 	this.screenOrientation = 0;
 
-	var onDeviceOrientationChangeEvent = function ( event ) {
+	this.alpha = 0;
+	this.alphaOffsetAngle = 0;
+
+
+	var onDeviceOrientationChangeEvent = function( event ) {
 
 		scope.deviceOrientation = event;
 
 	};
 
-	var onScreenOrientationChangeEvent = function () {
+	var onScreenOrientationChangeEvent = function() {
 
 		scope.screenOrientation = window.orientation || 0;
 
@@ -31,7 +35,7 @@ THREE.DeviceOrientationControls = function ( object ) {
 
 	// The angles alpha, beta and gamma form a set of intrinsic Tait-Bryan angles of type Z-X'-Y''
 
-	var setObjectQuaternion = function () {
+	var setObjectQuaternion = function() {
 
 		var zee = new THREE.Vector3( 0, 0, 1 );
 
@@ -41,15 +45,15 @@ THREE.DeviceOrientationControls = function ( object ) {
 
 		var q1 = new THREE.Quaternion( - Math.sqrt( 0.5 ), 0, 0, Math.sqrt( 0.5 ) ); // - PI/2 around the x-axis
 
-		return function ( quaternion, alpha, beta, gamma, orient ) {
+		return function( quaternion, alpha, beta, gamma, orient ) {
 
-			euler.set( beta, alpha, - gamma, 'YXZ' );                       // 'ZXY' for the device, but 'YXZ' for us
+			euler.set( beta, alpha, - gamma, 'YXZ' ); // 'ZXY' for the device, but 'YXZ' for us
 
-			quaternion.setFromEuler( euler );                               // orient the device
+			quaternion.setFromEuler( euler ); // orient the device
 
-			quaternion.multiply( q1 );                                      // camera looks out the back of the device, not the top
+			quaternion.multiply( q1 ); // camera looks out the back of the device, not the top
 
-			quaternion.multiply( q0.setFromAxisAngle( zee, - orient ) );    // adjust for screen orientation
+			quaternion.multiply( q0.setFromAxisAngle( zee, - orient ) ); // adjust for screen orientation
 
 		}
 
@@ -75,20 +79,28 @@ THREE.DeviceOrientationControls = function ( object ) {
 
 	};
 
-	this.update = function () {
+	this.update = function() {
 
 		if ( scope.enabled === false ) return;
 
-		var alpha  = scope.deviceOrientation.alpha ? THREE.Math.degToRad( scope.deviceOrientation.alpha ) : 0; // Z
-		var beta   = scope.deviceOrientation.beta  ? THREE.Math.degToRad( scope.deviceOrientation.beta  ) : 0; // X'
-		var gamma  = scope.deviceOrientation.gamma ? THREE.Math.degToRad( scope.deviceOrientation.gamma ) : 0; // Y''
-		var orient = scope.screenOrientation       ? THREE.Math.degToRad( scope.screenOrientation       ) : 0; // O
+		var alpha = scope.deviceOrientation.alpha ? THREE.Math.degToRad( scope.deviceOrientation.alpha ) + this.alphaOffsetAngle : 0; // Z
+		var beta = scope.deviceOrientation.beta ? THREE.Math.degToRad( scope.deviceOrientation.beta ) : 0; // X'
+		var gamma = scope.deviceOrientation.gamma ? THREE.Math.degToRad( scope.deviceOrientation.gamma ) : 0; // Y''
+		var orient = scope.screenOrientation ? THREE.Math.degToRad( scope.screenOrientation ) : 0; // O
 
 		setObjectQuaternion( scope.object.quaternion, alpha, beta, gamma, orient );
+		this.alpha = alpha;
+
+	};
+
+	this.updateAlphaOffsetAngle = function( angle ) {
+
+		this.alphaOffsetAngle = angle;
+		this.update();
 
 	};
 
-	this.dispose = function () {
+	this.dispose = function() {
 
 		this.disconnect();