Fix PicoVR 6dof hand detection (#2751)

For PicoVR 6dof controllers, the primary controller is the one with focus when the application
is launched. The is an additional call that determines which hand the primary controller is in.

Author: bluemarvin

app/src/picovr/cpp/native-lib.cpp

@@ -109,6 +109,14 @@ JNI_METHOD(void, nativeEndFrame)
   BrowserWorld::Instance().EndFrame();
 }
 
+JNI_METHOD(void, nativeSetFocusedController)
+(JNIEnv*, jobject, jint index) {
+  if (gDestroyed) {
+    return;
+  }
+  sDevice->SetFocused(index);
+}
+
 JNI_METHOD(void, nativeUpdateControllerPose)
 (JNIEnv*, jobject, jint index, jboolean dof6, jfloat px, jfloat py, jfloat pz, jfloat qx, jfloat qy, jfloat qz, jfloat qw) {
   if (gDestroyed) {

app/src/picovr/java/org/mozilla/vrbrowser/PlatformActivity.java

@@ -113,13 +113,18 @@ private void updateControllers() {
         }
 
         if (mControllerManager != null) {
+            int hand = VrActivity.getPvrHandness(this);
+            if (hand != mHand) {
+                nativeSetFocusedController(hand);
+                mHand = hand;
+            }
             CVController main = mControllerManager.getMainController();
             if (main != null) {
-                updateController(0, main);
+                updateController(hand, main);
             }
             CVController sub = mControllerManager.getSubController();
             if (sub != null) {
-                updateController(1, sub);
+                updateController(1 - hand, sub);
             }
         } else if (mHbManager != null) {
             update3DofController();
@@ -243,7 +248,8 @@ public void onRendererShutdown() {
 
     @Override
     public void initGL(int width, int height) {
-        nativeInitialize(width, height, getAssets(), mType, VrActivity.getPvrHandness(this));
+        mHand = VrActivity.getPvrHandness(this);
+        nativeInitialize(width, height, getAssets(), mType, mHand);
     }
 
     @Override
@@ -293,6 +299,7 @@ public void onChannelChanged(int var1, int var2) {
     protected native void nativeEndFrame();
     protected native void nativePause();
     protected native void nativeResume();
+    protected native void nativeSetFocusedController(int index);
     protected native void nativeUpdateControllerState(int index, boolean connected, int buttons, float grip, float axisX, float axisY, boolean touched);
     protected native void nativeUpdateControllerPose(int index, boolean dof6, float px, float py, float pz, float qx, float qy, float qz, float qw);
     protected native void queueRunnable(Runnable aRunnable);