Added Vive controller events. (#9586)

* Added Vive controller events.

* Reformatted for Doob-style.

* Fewer public variables, more API-like.

* Fixed how axisChanged is reported.

examples/js/ViveController.js

 /**
  * @author mrdoob / http://mrdoob.com
+ * @author stewdio / http://stewd.io
  */
 
-THREE.ViveController = function ( id ) {
+THREE.ViveController = function( id ) {
 
 	THREE.Object3D.call( this );
 
-	var scope = this;
-	var gamepad;
+	var
+	scope = this,
+	gamepad,
+	axes = [ 0, 0 ],
+	thumbpadIsPressed = false,
+	triggerIsPressed = false,
+	gripsArePressed = false,
+	menuIsPressed = false;
+
+	function dispatchViveControllerEvent( name, custom ) {
+
+		var data = {};
+
+		data.id = id;
+		data.gamepad = gamepad;
+		data.instance = scope;
+		if ( custom !== undefined ) Object.assign( data, custom );
+		window.dispatchEvent( new CustomEvent( 'viveController' + name, { detail: data } ) );
+
+	}
 
-	this.getGamepad = function () { return gamepad; };
 	this.matrixAutoUpdate = false;
 	this.standingMatrix = new THREE.Matrix4();
+	this.getGamepad = function() {
 
-	function update() {
+		return gamepad;
 
-		requestAnimationFrame( update );
+	}
+	this.getButtonState = function( button ) {
 
-		gamepad = navigator.getGamepads()[ id ];
+		return scope[ button + ( button === 'grips' ? 'ArePressed' : 'IsPressed' ) ];
 
+	}
+	this.update = function() {
+
+		var pose;
+
+		gamepad = navigator.getGamepads()[ id ];
 		if ( gamepad !== undefined && gamepad.pose !== null ) {
 
-			var pose = gamepad.pose;
 
+			//  Position and orientation.
+
+			pose = gamepad.pose;
 			scope.position.fromArray( pose.position );
 			scope.quaternion.fromArray( pose.orientation );
 			scope.matrix.compose( scope.position, scope.quaternion, scope.scale );
 			scope.matrix.multiplyMatrices( scope.standingMatrix, scope.matrix );
 			scope.matrixWorldNeedsUpdate = true;
-
 			scope.visible = true;
 
-		} else {
 
-			scope.visible = false;
+			//  Thumbpad and Buttons.
+
+			if ( axes[ 0 ] !== gamepad.axes[ 0 ] ||
+				axes[ 1 ] !== gamepad.axes[ 1 ] ) {
+
+				axes[ 0 ] = gamepad.axes[ 0 ];//  X axis: -1 = Left, +1 = Right.
+				axes[ 1 ] = gamepad.axes[ 1 ];//  Y axis: -1 = Bottom, +1 = Top.
+				dispatchViveControllerEvent( 'AxisChanged', { axes: axes } );
 
 			}
+			if ( thumbpadIsPressed !== gamepad.buttons[ 0 ].pressed ) {
+
+				thumbpadIsPressed = gamepad.buttons[ 0 ].pressed;
+				dispatchViveControllerEvent( thumbpadIsPressed ? 'ThumbpadPressed' : 'ThumbpadReleased' );
 
 			}
+			if ( triggerIsPressed !== gamepad.buttons[ 1 ].pressed ) {
 
-	update();
+				triggerIsPressed = gamepad.buttons[ 1 ].pressed;
+				dispatchViveControllerEvent( triggerIsPressed ? 'TriggerPressed' : 'TriggerReleased' );
+
+			}
+			if ( gripsArePressed !== gamepad.buttons[ 2 ].pressed ) {
+
+				gripsArePressed = gamepad.buttons[ 2 ].pressed;
+				dispatchViveControllerEvent( gripsArePressed ? 'GripsPressed' : 'GripsReleased' );
+
+			}
+			if ( menuIsPressed !== gamepad.buttons[ 3 ].pressed ) {
 
-};
+				menuIsPressed = gamepad.buttons[ 3 ].pressed;
+				dispatchViveControllerEvent( menuIsPressed ? 'MenuPressed' : 'MenuReleased' );
+
+			}
+
+		}
+		else scope.visible = false;
+
+	}
 
+}
 THREE.ViveController.prototype = Object.create( THREE.Object3D.prototype );
 THREE.ViveController.prototype.constructor = THREE.ViveController;