Source: vr/VRApp.js

/**
 *	@class VRApp
 *	@memberof SQR
 *
 *	@description A helper class to create universal VR Apps (i.e. that work on both mobile and desktop VR-enabled browsers)
 */
SQR.VRApp = function(appFunc, options) {
	options = options || {};
	options.isTouch = ('ontouchstart' in document);
	options.vrInput = null;
	options.vrData = {};
	var vrBtn, novrBtn, startInstr;
	var fsopt = {};
	
	var INSTR_COPY_DESKTOP 	= '<span>Put on your headset and press space when ready.</span>';
	var INSTR_COPY_MOBILE 	= '<span>Put on your headset and tap screen when ready.</span>';
	var BTN_COPY_VR   		= 'CARDBOARD';
	var BTN_COPY_NO_VR   	= 'NO CARDBOARD';
	var PORT_WARN_COPY   	= 'Please rotate your screen to landscape mode';
	var fullscreen = function(c) {
		if (c.requestFullscreen) {
			c.requestFullscreen(fsopt);
		} else if (c.msRequestFullscreen) {
			c.msRequestFullscreen(fsopt);
		} else if (c.mozRequestFullScreen) {
			c.mozRequestFullScreen(fsopt);
		} else if (c.webkitRequestFullscreen) {
			c.webkitRequestFullscreen(fsopt);
		}
	}
	var tryVR = function(onDone) {
		var vrHMD;		
		var onVRError = function(e) {
			console.log('VR: Error in navigator.getVRDevices()');
			console.log(e);
			onDone();
		}
		var onVRDevices = function(devices) {
			SQR.flipMatrix = false;
			for(var i = 0; i < devices.length; i++) {
				var d = devices[i];
				if(!options.vrInput && d instanceof PositionSensorVRDevice) options.vrInput = d;
				if(!vrHMD && d instanceof HMDVRDevice) vrHMD = d;
				fsopt.vrDisplay = vrHMD;
			}
			// console.log(options.vrInput);
			// console.log(vrHMD.getEyeParameters("left"));
			options.vrData.leftEyeX  =  vrHMD.getEyeParameters("left").eyeTranslation.x;
			options.vrData.rightEyeX = vrHMD.getEyeParameters("right").eyeTranslation.x;
			options.vrData.leftEyeFOV  =  vrHMD.getEyeParameters("left").recommendedFieldOfView;
			options.vrData.rightEyeFOV = vrHMD.getEyeParameters("right").recommendedFieldOfView;
			onDone();
		}
		if(!navigator.mozGetVRDevices && !navigator.getVRDevices) {
			console.log("VR: Your browser is not VR Ready");
			onDone();
			return;
		}
		if(navigator.getVRDevices) {
			navigator.getVRDevices().then(onVRDevices, onVRError);
		} else {
			navigator.mozGetVRDevices(onVRDevices);
		}
	}
	var onKeyDown = function(e) {
		if(e.keyCode == 32) {
			document.removeEventListener('keydown', onKeyDown);
			startApp();
		}
	}
	var startApp = function(e) {
		if(vrBtn) document.body.removeChild(vrBtn);
		if(novrBtn) document.body.removeChild(novrBtn);
		if(startInstr) document.body.removeChild(startInstr);
		if(options.isTouch || (options.vrInput && !options.debug)) fullscreen(document.body);
		if(appFunc) appFunc(options);
	}
	var prepare = function() {
		if(options.vrInput && !options.isTouch) {
			startInstr = document.createElement('div');
			startInstr.innerHTML = INSTR_COPY_DESKTOP + INSTR_COPY_DESKTOP;
			startInstr.setAttribute('class', 'instr');
			document.body.appendChild(startInstr);
			
			document.addEventListener('keydown', onKeyDown);
		} else if(options.isTouch) {
			vrBtn = document.createElement('div');
			vrBtn.setAttribute('class', 'start vr');
			vrBtn.innerHTML = BTN_COPY_VR;
			document.body.appendChild(vrBtn);
			novrBtn = document.createElement('div');
			novrBtn.setAttribute('class', 'start novr');
			novrBtn.innerHTML = BTN_COPY_NO_VR;
			document.body.appendChild(novrBtn);
			portWarn = document.createElement('div');
			portWarn.setAttribute('class', 'portrait-warning');
			portWarn.innerHTML = PORT_WARN_COPY;
			document.body.appendChild(portWarn);
			vrBtn.addEventListener('click', function() {
				options.forceStereo = true;
				startApp();
			});
			novrBtn.addEventListener('click', function() {
				options.forceMono = true;
				startApp();
			});
		} else {
			startApp();
		}	
	}
	tryVR(prepare);
};