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<!--
Copyright 2016 The Chromium Authors. All rights reserved.
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file.
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    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">
    <meta name="mobile-web-app-capable" content="yes">
    <meta name="apple-mobile-web-app-capable" content="yes">

    <!-- Origin Trial Token, feature = WebVR (For Chrome M62+), origin = https://webvr.info, expires = 2018-09-10 -->
<meta http-equiv="origin-trial" data-feature="WebVR (For Chrome M62+)" data-expires="2018-09-10" content="AhQcOrbjvS0+50wwuqtAidzraKNfZj8Bj159g2+2LsT5QRHe9IeebCl5ApORwd3oGxfKzl5H8s5K3aTMNzC+5gsAAABPeyJvcmlnaW4iOiJodHRwczovL3dlYnZyLmluZm86NDQzIiwiZmVhdHVyZSI6IldlYlZSMS4xTTYyIiwiZXhwaXJ5IjoxNTM2NjAxNDEzfQ==">


    <title>05 - Room Scale</title>

    <!--
      This sample demonstrates how to create scenes that align with the space
      physically available to the user (when that information is available).
    -->

    <style>
      #webgl-canvas {
        box-sizing: border-box;
        height: 100%;
        left: 0;
        margin: 0;
        position: absolute;
        top: 0;
        width: 100%;
      }
    </style>

    <!-- This entire block in only to facilitate dynamically enabling and
    disabling the WebVR polyfill, and is not necessary for most WebVR apps.
    If you want to use the polyfill in your app, just include the js file and
    everything will work the way you want it to by default. -->
    <script src="js/third-party/webvr-polyfill.js"></script>
    <script src="js/third-party/wglu/wglu-url.js"></script>
    <script>
      // Dynamically turn the polyfill on if requested by the query args.
      if (WGLUUrl.getBool('polyfill', false)) {
        var polyfill = new WebVRPolyfill({
          // Ensures the polyfill is always active on mobile, due to providing
          // a polyfilled CardboardVRDisplay when no native API is available,
          // and also polyfilling even when the native API is available, due to
          // providing a CardboardVRDisplay when no native VRDisplays exist.
          PROVIDE_MOBILE_VRDISPLAY: true,
          // Polyfill optimizations
          DIRTY_SUBMIT_FRAME_BINDINGS: true,
          BUFFER_SCALE: 0.75,
        });
      }
    </script>
    <!-- End sample polyfill enabling logic -->

    <script src="js/third-party/gl-matrix-min.js"></script>

    <script src="js/third-party/wglu/wglu-debug-geometry.js"></script>
    <script src="js/third-party/wglu/wglu-program.js"></script>
    <script src="js/third-party/wglu/wglu-stats.js"></script>
    <script src="js/third-party/wglu/wglu-texture.js"></script>

    <script src="js/vr-cube-island.js"></script>
    <script src="js/vr-samples-util.js"></script>
  </head>
  <body>
    <canvas id="webgl-canvas"></canvas>
    <script>
      /* global mat4, vec3, VRCubeIsland, WGLUDebugGeometry, WGLUStats, WGLUTextureLoader, VRSamplesUtil */
      (function () {
      "use strict";

      var PLAYER_HEIGHT = 1.65;

      var vrDisplay = null;
      var frameData = null;
      var projectionMat = mat4.create();
      var viewMat = mat4.create();
      var vrPresentButton = null;

      // ===================================================
      // WebGL scene setup. This code is not WebVR specific.
      // ===================================================

      // WebGL setup.
      var gl = null;
      var cubeIsland = null;
      var stats = null;
      var debugGeom = null;

      function onContextLost( event ) {
        event.preventDefault();
        console.log( 'WebGL Context Lost.' );
        gl = null;
        cubeIsland = null;
        debugGeom = null;
        stats = null;
      }

      function onContextRestored( event ) {
        console.log( 'WebGL Context Restored.' );
        initWebGL(vrDisplay ? vrDisplay.capabilities.hasExternalDisplay : false);
      }

      var webglCanvas = document.getElementById("webgl-canvas");
      webglCanvas.addEventListener( 'webglcontextlost', onContextLost, false );
      webglCanvas.addEventListener( 'webglcontextrestored', onContextRestored, false );

      function initWebGL (preserveDrawingBuffer) {
        var glAttribs = {
          alpha: false,
          preserveDrawingBuffer: preserveDrawingBuffer
        };
        var useWebgl2 = WGLUUrl.getBool('webgl2', false);
        var contextTypes = useWebgl2 ? ["webgl2"] : ["webgl", "experimental-webgl"];
        for (var i in contextTypes) {
          gl = webglCanvas.getContext(contextTypes[i], glAttribs);
          if (gl)
            break;
        }
        if (!gl) {
          var webglType = (useWebgl2 ? "WebGL 2" : "WebGL")
          VRSamplesUtil.addError("Your browser does not support " + webglType + ".");
          return;
        }
        gl.clearColor(0.1, 0.2, 0.3, 1.0);
        gl.enable(gl.DEPTH_TEST);
        gl.enable(gl.CULL_FACE);

        var textureLoader = new WGLUTextureLoader(gl);
        var texture = textureLoader.loadTexture("media/textures/cube-sea.png");

        // If the VRDisplay doesn't have stageParameters we won't know
        // how big the users play space. Construct a scene around a
        // default space size like 2 meters by 2 meters as a placeholder.
        cubeIsland = new VRCubeIsland(gl, texture, 2, 2);

        var enablePerformanceMonitoring = WGLUUrl.getBool(
            'enablePerformanceMonitoring', false);
        stats = new WGLUStats(gl, enablePerformanceMonitoring);
        debugGeom = new WGLUDebugGeometry(gl);

        // Wait until we have a WebGL context to resize and start rendering.
        window.addEventListener("resize", onResize, false);
        onResize();
        window.requestAnimationFrame(onAnimationFrame);
      }

      // ================================
      // WebVR-specific code begins here.
      // ================================

      function onVRRequestPresent () {
        vrDisplay.requestPresent([{ source: webglCanvas }]).then(function () {
        }, function (err) {
          var errMsg = "requestPresent failed.";
          if (err && err.message) {
            errMsg += "<br/>" + err.message
          }
          VRSamplesUtil.addError(errMsg, 2000);
        });
      }

      function onVRExitPresent () {
        if (!vrDisplay.isPresenting)
          return;

        vrDisplay.exitPresent().then(function () {
        }, function () {
          VRSamplesUtil.addError("exitPresent failed.", 2000);
        });
      }

      function onVRPresentChange () {
        onResize();

        if (vrDisplay.isPresenting) {
          if (vrDisplay.capabilities.hasExternalDisplay) {
            VRSamplesUtil.removeButton(vrPresentButton);
            vrPresentButton = VRSamplesUtil.addButton("Exit VR", "E", "media/icons/cardboard64.png", onVRExitPresent);
          }
        } else {
          if (vrDisplay.capabilities.hasExternalDisplay) {
            VRSamplesUtil.removeButton(vrPresentButton);
            vrPresentButton = VRSamplesUtil.addButton("Enter VR", "E", "media/icons/cardboard64.png", onVRRequestPresent);
          }
        }
      }

      if (navigator.getVRDisplays) {
        frameData = new VRFrameData();

        navigator.getVRDisplays().then(function (displays) {
          if (displays.length > 0) {
            vrDisplay = displays[displays.length - 1];
            vrDisplay.depthNear = 0.1;
            vrDisplay.depthFar = 1024.0;

            initWebGL(vrDisplay.capabilities.hasExternalDisplay);

            if (vrDisplay.stageParameters &&
                vrDisplay.stageParameters.sizeX > 0 &&
                vrDisplay.stageParameters.sizeZ > 0) {
              // If we have stageParameters with a valid size use that to resize
              // our scene to match the users available space more closely. The
              // check for size > 0 is necessary because some devices, like the
              // Oculus Rift, can give you a standing space coordinate but don't
              // have a configured play area. These devices will return a stage
              // size of 0.
              cubeIsland.resize(vrDisplay.stageParameters.sizeX, vrDisplay.stageParameters.sizeZ);
            } else {
              if (vrDisplay.stageParameters) {
                VRSamplesUtil.addInfo("VRDisplay reported stageParameters, but stage size was 0. Using default size.", 3000);
              } else {
                VRSamplesUtil.addInfo("VRDisplay did not report stageParameters", 3000);
              }
            }

            if (vrDisplay.capabilities.canPresent)
              vrPresentButton = VRSamplesUtil.addButton("Enter VR", "E", "media/icons/cardboard64.png", onVRRequestPresent);

            // For the benefit of automated testing. Safe to ignore.
            if (vrDisplay.capabilities.canPresent && WGLUUrl.getBool('canvasClickPresents', false))
              webglCanvas.addEventListener("click", onVRRequestPresent, false);

            window.addEventListener('vrdisplaypresentchange', onVRPresentChange, false);
            window.addEventListener('vrdisplayactivate', onVRRequestPresent, false);
            window.addEventListener('vrdisplaydeactivate', onVRExitPresent, false);
          } else {
            initWebGL(false);
            VRSamplesUtil.addInfo("WebVR supported, but no VRDisplays found.", 3000);
          }
        }, function () {
          VRSamplesUtil.addError("Your browser does not support WebVR. See <a href='http://webvr.info'>webvr.info</a> for assistance.");
        });
      } else if (navigator.getVRDevices) {
        initWebGL(false);
        VRSamplesUtil.addError("Your browser supports WebVR but not the latest version. See <a href='http://webvr.info'>webvr.info</a> for more info.");
      } else {
        initWebGL(false);
        VRSamplesUtil.addError("Your browser does not support WebVR. See <a href='http://webvr.info'>webvr.info</a> for assistance.");
      }

      function onResize () {
        if (vrDisplay && vrDisplay.isPresenting) {
          var leftEye = vrDisplay.getEyeParameters("left");
          var rightEye = vrDisplay.getEyeParameters("right");

          webglCanvas.width = Math.max(leftEye.renderWidth, rightEye.renderWidth) * 2;
          webglCanvas.height = Math.max(leftEye.renderHeight, rightEye.renderHeight);
        } else {
          webglCanvas.width = webglCanvas.offsetWidth * window.devicePixelRatio;
          webglCanvas.height = webglCanvas.offsetHeight * window.devicePixelRatio;
        }
      }

      function onClick () {
        // Reset the background color to a random value
        if (gl) {
          gl.clearColor(
            Math.random() * 0.5,
            Math.random() * 0.5,
            Math.random() * 0.5, 1.0);
        }
      }

      // Register for mouse restricted events while in VR
      // (e.g. mouse no longer available on desktop 2D view)
      function onDisplayPointerRestricted() {
        if (webglCanvas && webglCanvas.requestPointerLock) {
          webglCanvas.requestPointerLock();
        }
      }

      // Register for mouse unrestricted events while in VR
      // (e.g. mouse once again available on desktop 2D view)
      function onDisplayPointerUnrestricted() {
        var lock = document.pointerLockElement;
        if (lock && lock === webglCanvas && document.exitPointerLock) {
          document.exitPointerLock();
        }
      }

      VRSamplesUtil.addVRClickListener(onClick);
      webglCanvas.addEventListener("click", onClick, false);
      window.addEventListener('vrdisplaypointerrestricted', onDisplayPointerRestricted);
      window.addEventListener('vrdisplaypointerunrestricted', onDisplayPointerUnrestricted);

      // Get a matrix for the pose that takes into account the stageParameters
      // if we have them, and otherwise adjusts the position to ensure we're
      // not stuck in the floor.
      function getStandingViewMatrix (out, view) {
        if (vrDisplay.stageParameters) {
          // If the headset provides stageParameters use the
          // sittingToStandingTransform to transform the view matrix into a
          // space where the floor in the center of the users play space is the
          // origin.
          mat4.invert(out, vrDisplay.stageParameters.sittingToStandingTransform);
          mat4.multiply(out, view, out);
        } else {
          // Otherwise you'll want to translate the view to compensate for the
          // scene floor being at Y=0. Ideally this should match the user's
          // height (you may want to make it configurable). For this demo we'll
          // just assume all human beings are 1.65 meters (~5.4ft) tall.
          mat4.identity(out);
          mat4.translate(out, out, [0, PLAYER_HEIGHT, 0]);
          mat4.invert(out, out);
          mat4.multiply(out, view, out);
        }
      }

      function renderSceneView (projection, view, pose) {
        cubeIsland.render(projection, view, stats);

        // For fun, draw a blue cube where the players head would have been if
        // we weren't taking the stageParameters into account. It'll start in
        // the center of the floor.
        var orientation = pose.orientation;
        var position = pose.position;
        if (!orientation) { orientation = [0, 0, 0, 1]; }
        if (!position) { position = [0, 0, 0]; }
        debugGeom.bind(projection, view);
        debugGeom.drawCube(orientation, position, 0.2, [0, 0, 1, 1]);
      }

      function onAnimationFrame (t) {
        // do not attempt to render if there is no available WebGL context
        if (!gl || !stats || !cubeIsland || !debugGeom) {
          return;
        }
        stats.begin();

        gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

        if (vrDisplay) {
          vrDisplay.requestAnimationFrame(onAnimationFrame);

          vrDisplay.getFrameData(frameData);

          if (vrDisplay.isPresenting) {
            gl.viewport(0, 0, webglCanvas.width * 0.5, webglCanvas.height);
            getStandingViewMatrix(viewMat, frameData.leftViewMatrix);
            renderSceneView(frameData.leftProjectionMatrix, viewMat, frameData.pose);

            gl.viewport(webglCanvas.width * 0.5, 0, webglCanvas.width * 0.5, webglCanvas.height);
            getStandingViewMatrix(viewMat, frameData.rightViewMatrix);
            renderSceneView(frameData.rightProjectionMatrix, viewMat, frameData.pose);

            vrDisplay.submitFrame();
          } else {
            gl.viewport(0, 0, webglCanvas.width, webglCanvas.height);
            mat4.perspective(projectionMat, Math.PI*0.4, webglCanvas.width / webglCanvas.height, 0.1, 1024.0);
            getStandingViewMatrix(viewMat, frameData.leftViewMatrix);
            renderSceneView(projectionMat, viewMat, frameData.pose);
            stats.renderOrtho();
          }
        } else {
          window.requestAnimationFrame(onAnimationFrame);

          // No VRDisplay found.
          gl.viewport(0, 0, webglCanvas.width, webglCanvas.height);
          mat4.perspective(projectionMat, Math.PI*0.4, webglCanvas.width / webglCanvas.height, 0.1, 1024.0);
          mat4.identity(viewMat);
          mat4.translate(viewMat, viewMat, [0, -PLAYER_HEIGHT, 0]);
          cubeIsland.render(projectionMat, viewMat, stats);

          stats.renderOrtho();
        }

        stats.end();
      }
      })();
    </script>
  </body>
</html>