<!-- SRC: https://threejs.org/examples/#webgl_performance

PHOTO: https://raw.githubusercontent.com/mrdoob/three.js/master/examples/textures/2294472375_24a3b8ef46_o.jpg
-->


<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">


		<div id="container"></div>
		<div id="info">
			<a href="https://threejs.org" target="_blank">three.js webgl</a> - equirectangular panorama demo. photo by <a href="http://www.flickr.com/photos/jonragnarsson/2294472375/" target="_blank">Jón Ragnarsson</a>.<br />
			drag equirectangular texture into the page.
		</div>

			body {
				background-color: #000000;
				margin: 0px;
				overflow: hidden;
			}

			#info {
				position: absolute;
				top: 0px; width: 100%;
				color: #ffffff;
				padding: 5px;
				font-family:Monospace;
				font-size:13px;
				font-weight: bold;
				text-align:center;
			}

			a {
				color: #ffffff;
			}

			var camera, scene, renderer;

			var isUserInteracting = false,
			onMouseDownMouseX = 0, onMouseDownMouseY = 0,
			lon = 0, onMouseDownLon = 0,
			lat = 0, onMouseDownLat = 0,
			phi = 0, theta = 0;

			init();
			animate();

			function init() {

				var container, mesh;

				container = document.getElementById( 'container' );

				camera = new THREE.PerspectiveCamera( 75, window.innerWidth / window.innerHeight, 1, 1100 );
				camera.target = new THREE.Vector3( 0, 0, 0 );

				scene = new THREE.Scene();

				var geometry = new THREE.SphereGeometry( 500, 60, 40 );
				geometry.scale( - 1, 1, 1 );

				var material = new THREE.MeshBasicMaterial( {
					map: new THREE.TextureLoader().load( 'https://raw.githubusercontent.com/mrdoob/three.js/master/examples/textures/2294472375_24a3b8ef46_o.jpg' )
				} );

				mesh = new THREE.Mesh( geometry, material );

				scene.add( mesh );

				renderer = new THREE.WebGLRenderer();
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );
				container.appendChild( renderer.domElement );

				document.addEventListener( 'mousedown', onDocumentMouseDown, false );
				document.addEventListener( 'mousemove', onDocumentMouseMove, false );
				document.addEventListener( 'mouseup', onDocumentMouseUp, false );
				document.addEventListener( 'wheel', onDocumentMouseWheel, false );

				//

				document.addEventListener( 'dragover', function ( event ) {

					event.preventDefault();
					event.dataTransfer.dropEffect = 'copy';

				}, false );

				document.addEventListener( 'dragenter', function ( event ) {

					document.body.style.opacity = 0.5;

				}, false );

				document.addEventListener( 'dragleave', function ( event ) {

					document.body.style.opacity = 1;

				}, false );

				document.addEventListener( 'drop', function ( event ) {

					event.preventDefault();

					var reader = new FileReader();
					reader.addEventListener( 'load', function ( event ) {

						material.map.image.src = event.target.result;
						material.map.needsUpdate = true;

					}, false );
					reader.readAsDataURL( event.dataTransfer.files[ 0 ] );

					document.body.style.opacity = 1;

				}, false );

				//

				window.addEventListener( 'resize', onWindowResize, false );

			}

			function onWindowResize() {

				camera.aspect = window.innerWidth / window.innerHeight;
				camera.updateProjectionMatrix();

				renderer.setSize( window.innerWidth, window.innerHeight );

			}

			function onDocumentMouseDown( event ) {

				event.preventDefault();

				isUserInteracting = true;

				onPointerDownPointerX = event.clientX;
				onPointerDownPointerY = event.clientY;

				onPointerDownLon = lon;
				onPointerDownLat = lat;

			}

			function onDocumentMouseMove( event ) {

				if ( isUserInteracting === true ) {

					lon = ( onPointerDownPointerX - event.clientX ) * 0.1 + onPointerDownLon;
					lat = ( event.clientY - onPointerDownPointerY ) * 0.1 + onPointerDownLat;

				}

			}

			function onDocumentMouseUp( event ) {

				isUserInteracting = false;

			}

			function onDocumentMouseWheel( event ) {

				camera.fov += event.deltaY * 0.05;
				camera.updateProjectionMatrix();

			}

			function animate() {

				requestAnimationFrame( animate );
				update();

			}

			function update() {

				if ( isUserInteracting === false ) {

					lon += 0.1;

				}

				lat = Math.max( - 85, Math.min( 85, lat ) );
				phi = THREE.Math.degToRad( 90 - lat );
				theta = THREE.Math.degToRad( lon );

				camera.target.x = 500 * Math.sin( phi ) * Math.cos( theta );
				camera.target.y = 500 * Math.cos( phi );
				camera.target.z = 500 * Math.sin( phi ) * Math.sin( theta );

				camera.lookAt( camera.target );

				/*
				// distortion
				camera.position.copy( camera.target ).negate();
				*/

				renderer.render( scene, camera );

			}