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<html>
  <head>
    <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 = WebXR Device API, origin = https://immersive-web.github.io, expires = 2018-08-28 -->
<meta http-equiv="origin-trial" data-feature="WebXR Device API" data-expires="2018-08-28" content="AnNpu7ceXvLew05ccD8Zr1OZsdZiB2hLQKK82kTTMDwF7oRKtP3QEJ4RzkeHrmB8Sq0vSV6ZNmszpBCZ0I8p9gAAAABceyJvcmlnaW4iOiJodHRwczovL2ltbWVyc2l2ZS13ZWIuZ2l0aHViLmlvOjQ0MyIsImZlYXR1cmUiOiJXZWJYUkRldmljZSIsImV4cGlyeSI6MTUzNTQxNDQwMH0=">

    <title>Pointer Painter</title>

    <link href='../css/common.css' rel='stylesheet'></link>

    <!--The polyfill is not needed for browser that have native API support,
        but is linked by these samples for wider compatibility.-->
    <!--script src='https://cdn.jsdelivr.net/npm/webxr-polyfill@latest/build/webxr-polyfill.js'></script-->
    <script src='../js/webxr-polyfill.js'></script>

    <script src='../js/webxr-button.js'></script>
  </head>
  <body>
    <header>
      <details open>
        <summary>Pointer painter</summary>
        <p>
          Leaves behind a trail of pointers and cursors on select events. Useful
          for testing screen input.
          <a class="back" href="./">Back</a>
        </p>
      </details>
    </header>
    <script type="module">
      import {Scene} from '../js/cottontail/src/scenes/scene.js';
      import {Renderer, createWebGLContext} from '../js/cottontail/src/core/renderer.js';
      import {Gltf2Node} from '../js/cottontail/src/nodes/gltf2.js';
      import {QueryArgs} from '../js/cottontail/src/util/query-args.js';
      import {FallbackHelper} from '../js/cottontail/src/util/fallback-helper.js';

      // If requested, initialize the WebXR polyfill
      if (QueryArgs.getBool('allowPolyfill', false)) {
        var polyfill = new WebXRPolyfill();
      }

      // XR globals.
      let xrButton = null;
      let xrImmersiveRefSpace = null;
      let xrNonImmersiveRefSpace = null;

      // WebGL scene globals.
      let gl = null;
      let renderer = null;
      let scene = new Scene();
      scene.addNode(new Gltf2Node({url: '../../media/gltf/garage/garage.gltf'}));
      scene.enableStats(false);
      scene._resetInputEndFrame = false;

      function initXR() {
        xrButton = new XRDeviceButton({
          onRequestSession: onRequestSession,
          onEndSession: onEndSession
        });
        document.querySelector('header').appendChild(xrButton.domElement);

        if (navigator.xr) {
          navigator.xr.supportsSessionMode('immersive-vr').then(() => {
            xrButton.enabled = true;
          });

          navigator.xr.requestSession().then(onSessionStarted);
        } else {
          initFallback();
        }
      }

      function initFallback() {
        initGL();
        document.body.appendChild(gl.canvas);
        let fallbackHelper = new FallbackHelper(scene, gl);
        fallbackHelper.emulateStage = true;
      }

      function initGL() {
        if (gl)
          return;

        gl = createWebGLContext({
          xrCompatible: true
        });

        renderer = new Renderer(gl);
        scene.setRenderer(renderer);
        scene.inputRenderer.setControllerMesh(new Gltf2Node({url: '../../media/gltf/controller/controller.gltf'}));
      }

      function onRequestSession() {
        navigator.xr.requestSession({ mode: 'immersive-vr' }).then((session) => {
          xrButton.setSession(session);
          onSessionStarted(session);
        });
      }

      function onSessionStarted(session) {
        session.addEventListener('end', onSessionEnded);

        session.addEventListener('selectstart', onSelectStart);
        session.addEventListener('selectend', onSelectEnd);
        session.addEventListener('select', onSelect);

        initGL();

        let outputCanvas = document.createElement('canvas');
        document.body.appendChild(outputCanvas);

        session.updateRenderState({
            baseLayer: new XRWebGLLayer(session, gl),
            outputContext: outputCanvas.getContext('xrpresent')
        });

        session.requestReferenceSpace({ type: 'stationary', subtype: 'floor-level' }).then((refSpace) => {
          if (session.mode.startsWith('immersive')) {
            xrImmersiveRefSpace = refSpace;
          } else {
            xrNonImmersiveRefSpace = refSpace;
          }

          session.requestAnimationFrame(onXRFrame);
        });
      }

      let selecting = false;

      function onSelectStart(ev) {
        selecting = true;
      }

      function onSelectEnd(ev) {
        selecting = false;
      }

      function onSelect(ev) {
        let session = ev.frame.session;
        let refSpace = session.mode.startsWith('immersive') ?
                         xrImmersiveRefSpace :
                         xrNonImmersiveRefSpace;
        let inputPose = ev.frame.getInputPose(ev.inputSource, refSpace);
        if (!inputPose) {
          return;
        }

        if (inputPose.targetRay) {
          scene.inputRenderer.addLaserPointer(inputPose.targetRay);

          let cursorDistance = 2.0;
          let cursorPos = vec3.fromValues(
              inputPose.targetRay.origin.x,
              inputPose.targetRay.origin.y,
              inputPose.targetRay.origin.z
              );
          vec3.add(cursorPos, cursorPos, [
              inputPose.targetRay.direction.x * cursorDistance,
              inputPose.targetRay.direction.y * cursorDistance,
              inputPose.targetRay.direction.z * cursorDistance,
              ]);
          scene.inputRenderer.addCursor(cursorPos);
        }
      }

      function updateInputSources(session, frame, refSpace) {
        let inputSources = session.getInputSources();

        for (let inputSource of inputSources) {
          let inputPose = frame.getInputPose(inputSource, refSpace);

          if (!inputPose) {
            continue;
          }

          if (inputPose.gripTransform && inputPose.gripTransform.matrix) {
            scene.inputRenderer.addController(inputPose.gripTransform.matrix);
          }

          if (inputPose.targetRay && selecting) {
            scene.inputRenderer.addLaserPointer(inputPose.targetRay);
          }
        }
      }

      function onEndSession(session) {
        session.end();
      }

      function onSessionEnded(event) {
        if (event.session.mode.startsWith('immersive')) {
          xrButton.setSession(null);
        }

        if (event.session.renderState.outputContext) {
          document.body.removeChild(event.session.renderState.outputContext.canvas);
        }
      }

      function onXRFrame(t, frame) {
        let session = frame.session;
        let refSpace = session.mode.startsWith('immersive') ?
                         xrImmersiveRefSpace :
                         xrNonImmersiveRefSpace;
        let pose = frame.getViewerPose(refSpace);

        scene.startFrame();

        session.requestAnimationFrame(onXRFrame);

        updateInputSources(session, frame, refSpace);

        scene.drawXRFrame(frame, pose);

        scene.endFrame();
        scene.inputRenderer.reset({ controllers: true })
      }

      // Start the XR application.
      initXR();
    </script>
  </body>
</html>