Fix mirror window displaying blank for Oculus Rift

jme3-vr/src/main/java/com/jme3/app/VRAppState.java

@@ -34,6 +34,7 @@ package com.jme3.app;
 import com.jme3.app.Application;
 import com.jme3.app.state.AbstractAppState;
 import com.jme3.app.state.AppStateManager;
+import com.jme3.input.vr.OculusVR;
 import com.jme3.input.vr.VRAPI;
 import com.jme3.input.vr.VRInputAPI;
 import com.jme3.math.ColorRGBA;
@@ -608,8 +609,12 @@ public class VRAppState extends AbstractAppState {
             settings.setFrequency(environment.getVRHardware().getDisplayFrequency());
             settings.setFullscreen(false);
             settings.setVSync(false); // stop vsyncing on primary monitor!
+
+            // TODO: Is this preventing desktop display on _ALL_ HMDs?
+            if(!(getVRHardware() instanceof OculusVR)) {
                 settings.setSwapBuffers(environment.isSwapBuffers());
             }
+        }
 
         // Updating application settings
         stateManager.getApplication().setSettings(settings);

jme3-vr/src/main/java/com/jme3/util/VRViewManagerOculus.java

@@ -135,9 +135,19 @@ public class VRViewManagerOculus extends AbstractVRViewManager {
             finalRotation.multLocal(hmdRot);
         }
 
+        // Update both eye cameras
         finalizeCamera(hardware.getHMDVectorPoseLeftEye(), objPos, leftCamera);
         finalizeCamera(hardware.getHMDVectorPoseRightEye(), objPos, rightCamera);
 
+        // Update the main camera, so it shows the same basic view the HMD is getting
+        // TODO: Do this in VRAppState, so it works on all HMDs.
+        // I only have a Rift, so I can't test it on anything else.
+        if(!environment.isInstanceRendering()) { // We use the app camera as the left camera here
+            // TODO: Double up on rendering and use one eye, to reduce GPU load rendering the scene again.
+            // TODO: Snip at the image to remove the distorted corners from a very high FOV.
+            finalizeCamera(Vector3f.ZERO, objPos, environment.getApplication().getCamera());
+        }
+
         if (environment.hasTraditionalGUIOverlay()) {
             // update the mouse?
             environment.getVRMouseManager().update(tpf);