Adding Chrome-side WebVR interface

content/public/android/java/src/org/chromium/content/browser/input/CardboardVRDevice.java

+// Copyright 2013 The Chromium Authors. All rights reserved.

[no sievers, 2015/03/19 01:24:52]

nit: 2015

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.content.browser.input;
+
+import android.content.Context;
+import android.os.Handler;
+import android.os.HandlerThread;
+import android.util.Log;
+
+import com.google.vrtoolkit.cardboard.CardboardDeviceParams;
+import com.google.vrtoolkit.cardboard.FieldOfView;
+import com.google.vrtoolkit.cardboard.HeadMountedDisplay;
+import com.google.vrtoolkit.cardboard.HeadMountedDisplayManager;
+import com.google.vrtoolkit.cardboard.ScreenParams;
+import com.google.vrtoolkit.cardboard.sensors.HeadTracker;
+import com.google.vrtoolkit.cardboard.sensors.MagnetSensor;
+
+import org.chromium.base.CalledByNative;
+import org.chromium.base.JNINamespace;
+
+/**
+ * This is the implementation of the C++ counterpart CardboardVRDevice.
+ */
+@JNINamespace("content")
+class CardboardVRDevice implements MagnetSensor.OnCardboardTriggerListener {
+    private static final String TAG = "CardboardVRDevice";
+    private HeadMountedDisplayManager mHMDManager;
+    private HeadTracker mHeadTracker;
+    private long mVrDevicePtr;
+    private HandlerThread mSensorObserverThread;
+    private Handler mSensorHandler;
+    private MagnetSensor mMagnetSensor;
+
+    @CalledByNative
+    private static CardboardVRDevice create(Context context, long vrDevicePtr) {
+        return new CardboardVRDevice(context, vrDevicePtr);
+    }
+
+    private CardboardVRDevice(Context context, long vrDevicePtr) {
+        mVrDevicePtr = vrDevicePtr;
+
+        mHMDManager = new HeadMountedDisplayManager(context);
+
+        mHeadTracker = HeadTracker.createFromContext(context);
+        mHeadTracker.setNeckModelEnabled(true);
+        mHeadTracker.startTracking();
+
+        mMagnetSensor = new MagnetSensor(context);
+        startObservingCardboardSensors();
+    }
+
+    @CalledByNative
+    private void getFieldOfView(float[] outFov) {
+        HeadMountedDisplay hmd = mHMDManager.getHeadMountedDisplay();
+        CardboardDeviceParams deviceParams = hmd.getCardboardDeviceParams();
+        FieldOfView fov = deviceParams.getLeftEyeMaxFov();
+        outFov[0] = fov.getTop();
+        outFov[1] = fov.getBottom();
+        outFov[2] = fov.getLeft();
+        outFov[3] = fov.getRight();
+    }
+
+    @CalledByNative
+    private float getIPD() {
+        HeadMountedDisplay hmd = mHMDManager.getHeadMountedDisplay();
+        CardboardDeviceParams deviceParams = hmd.getCardboardDeviceParams();
+        return deviceParams.getInterLensDistance();
+    }
+
+    @CalledByNative
+    private String getDeviceName() {
+        HeadMountedDisplay hmd = mHMDManager.getHeadMountedDisplay();
+        CardboardDeviceParams deviceParams = hmd.getCardboardDeviceParams();
+        return deviceParams.getVendor() + " " + deviceParams.getModel();
+    }
+
+    @CalledByNative
+    private void getScreenSize(int[] outSize) {
+        HeadMountedDisplay hmd = mHMDManager.getHeadMountedDisplay();
+        ScreenParams screenParams = hmd.getScreenParams();
+        outSize[0] = screenParams.getWidth();
+        outSize[1] = screenParams.getHeight();
+    }
+
+    @CalledByNative
+    private void getSensorState(float[] outMatrix) {
+        mHeadTracker.getLastHeadView(outMatrix, 0);
+    }
+
+    @CalledByNative
+    private void stopTracking() {
+        mHeadTracker.stopTracking();
+        stopObservingCardboardSensors();
+    }
+
+    @CalledByNative
+    private void resetSensor() {
+        mHeadTracker.resetTracker();
+    }
+
+    @Override
+    public void onCardboardTrigger() {
+        Log.d(TAG, "onCardboardTrigger");

[no sievers, 2015/03/19 01:24:52]

that's spammy

+        nativeOnCardboardTrigger(mVrDevicePtr);
+    }
+
+    private native void nativeOnCardboardTrigger(long vrDevicePtr);
+
+    private void startObservingCardboardSensors() {
+        if (mSensorObserverThread != null)
+            return;
+        final CardboardVRDevice listener = this;
+
+        mSensorObserverThread = new HandlerThread("MagnetObserver");
+        mSensorObserverThread.start();
+
+        mSensorHandler =  new Handler(mSensorObserverThread.getLooper());
+        mSensorHandler.post(new Runnable() {
+            @Override
+            public void run() {
+                mMagnetSensor.setOnCardboardTriggerListener(listener);
+                mMagnetSensor.start();
+            }
+        });
+    }
+
+    private void stopObservingCardboardSensors() {
+        final CardboardVRDevice listener = this;

[no sievers, 2015/03/19 01:24:52]

unused var

+        mMagnetSensor.stop();

[no sievers, 2015/03/19 01:24:52]

Is it ok to call this from a thread different than the observer thread created
above?

+
+        if (mSensorObserverThread == null)
+            return;
+
+        mSensorObserverThread.quit();
+        try {
+            mSensorObserverThread.join();
+        } catch (InterruptedException e) {
+            Log.e(TAG, "Thread.join() exception: ", e);
+        }
+        mSensorObserverThread = null;
+    }
+}