<!DOCTYPE html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/webxr_util.js"></script>
<script src="resources/webxr_test_constants.js"></script>

<script>
let testName = "XRViewport attributes are valid";

let fakeDeviceInitParams = TRACKED_IMMERSIVE_DEVICE;

let testFunction = function(session, fakeDeviceController, t, sessionObjects) {
  return session.requestReferenceSpace('local')
    .then((referenceSpace) => new Promise((resolve) =>{
      let webglLayer = sessionObjects.glLayer;
      function onFrame(time, xrFrame) {
        t.step(() => {
          let pose = xrFrame.getViewerPose(referenceSpace);
          assert_not_equals(pose, null);
          assert_not_equals(pose.views, null);

          if (session.sessionInit['optionalFeatures'].includes('secondary-views')) {
            assert_equals(pose.views.length, 3);
          } else {
            assert_equals(pose.views.length, 2);
          }

          // Ensure the views report the expected viewports into the WebGL layer.
          for (let i = 0; i < pose.views.length; i++) {
            let view = pose.views[i];
            let viewport = webglLayer.getViewport(view);

            assert_not_equals(viewport, null);
            assert_true(viewport instanceof XRViewport);

            // Exact viewport values don't matter, but they must pass several tests:

            // Viewports have non-zero widths and heights.
            assert_greater_than(viewport.width, 0);
            assert_greater_than(viewport.height, 0);

            // Viewports are located within the framebuffer.
            assert_greater_than_equal(viewport.x, 0);
            assert_greater_than_equal(viewport.y, 0);

            assert_less_than_equal(
              viewport.x + viewport.width, webglLayer.framebufferWidth);
            assert_less_than_equal(
              viewport.y + viewport.height, webglLayer.framebufferHeight);

              // Assume that the viewports are ordered from left to right. This is
            // not a requirement by the WebXR spec, but is a sanity check since
            // this is how Blink orders them.
            if (i != 0) {
              let previousView = pose.views[i - 1];
              let previousViewport = webglLayer.getViewport(previousView);
              assert_less_than_equal(previousViewport.x + previousViewport.width, viewport.x);
            }
          }
        });

        resolve();
      }
      session.requestAnimationFrame(onFrame);
  }));
};

xr_session_promise_test(
  testName, testFunction, fakeDeviceInitParams, 'immersive-vr',
  {'optionalFeatures': []});

xr_session_promise_test(
  testName + ' with secondary views requested', testFunction, fakeDeviceInitParams, 'immersive-vr',
  {'optionalFeatures': ['secondary-views']});

</script>
