do not mirror back camera. fixes #3693

src/main/java/eu/siacs/conversations/ui/RtpSessionActivity.java

@@ -639,14 +639,14 @@ public class RtpSessionActivity extends XmppActivity implements XmppConnectionSe
     }
 
     private void switchCamera(final View view) {
-        Futures.addCallback(requireRtpConnection().switchCamera(), new FutureCallback<Void>() {
+        Futures.addCallback(requireRtpConnection().switchCamera(), new FutureCallback<Boolean>() {
             @Override
-            public void onSuccess(@NullableDecl Void result) {
+            public void onSuccess(@NullableDecl Boolean isFrontCamera) {
-
+                binding.localVideo.setMirror(isFrontCamera);
             }
 
             @Override
-            public void onFailure(final Throwable throwable) {
+            public void onFailure(@NonNull final Throwable throwable) {
                 Log.d(Config.LOGTAG,"could not switch camera", Throwables.getRootCause(throwable));
                 Toast.makeText(RtpSessionActivity.this, R.string.could_not_switch_camera, Toast.LENGTH_LONG).show();
             }
@@ -715,7 +715,7 @@ public class RtpSessionActivity extends XmppActivity implements XmppConnectionSe
             ensureSurfaceViewRendererIsSetup(binding.localVideo);
             //paint local view over remote view
             binding.localVideo.setZOrderMediaOverlay(true);
-            binding.localVideo.setMirror(true);
+            binding.localVideo.setMirror(requireRtpConnection().isFrontCamera());
             localVideoTrack.get().addSink(binding.localVideo);
         } else {
             binding.localVideo.setVisibility(View.GONE);

src/main/java/eu/siacs/conversations/xmpp/jingle/JingleRtpConnection.java

@@ -1043,7 +1043,11 @@ public class JingleRtpConnection extends AbstractJingleConnection implements Web
         return webRTCWrapper.isCameraSwitchable();
     }
 
-    public ListenableFuture<Void> switchCamera() {
+    public boolean isFrontCamera() {
+        return webRTCWrapper.isFrontCamera();
+    }
+
+    public ListenableFuture<Boolean> switchCamera() {
         return webRTCWrapper.switchCamera();
     }
 

src/main/java/eu/siacs/conversations/xmpp/jingle/WebRTCWrapper.java

@@ -277,16 +277,22 @@ public class WebRTCWrapper {
         return capturerChoice != null && capturerChoice.availableCameras.size() > 1;
     }
 
-    ListenableFuture<Void> switchCamera() {
+    boolean isFrontCamera() {
+        final CapturerChoice capturerChoice = this.capturerChoice;
+        return capturerChoice == null || capturerChoice.isFrontCamera;
+    }
+
+    ListenableFuture<Boolean> switchCamera() {
         final CapturerChoice capturerChoice = this.capturerChoice;
         if (capturerChoice == null) {
             return Futures.immediateFailedFuture(new IllegalStateException("CameraCapturer has not been initialized"));
         }
-        final SettableFuture<Void> future = SettableFuture.create();
+        final SettableFuture<Boolean> future = SettableFuture.create();
         capturerChoice.cameraVideoCapturer.switchCamera(new CameraVideoCapturer.CameraSwitchHandler() {
             @Override
             public void onCameraSwitchDone(boolean isFrontCamera) {
-                future.set(null);
+                capturerChoice.isFrontCamera = isFrontCamera;
+                future.set(isFrontCamera);
             }
 
             @Override
@@ -438,7 +444,12 @@ public class WebRTCWrapper {
         final Set<String> deviceNames = ImmutableSet.copyOf(enumerator.getDeviceNames());
         for (final String deviceName : deviceNames) {
             if (enumerator.isFrontFacing(deviceName)) {
-                return Optional.fromNullable(of(enumerator, deviceName, deviceNames));
+                final CapturerChoice capturerChoice = of(enumerator, deviceName, deviceNames);
+                if (capturerChoice == null) {
+                    return Optional.absent();
+                }
+                capturerChoice.isFrontCamera = true;
+                return Optional.of(capturerChoice);
             }
         }
         if (deviceNames.size() == 0) {
@@ -548,6 +559,7 @@ public class WebRTCWrapper {
         private final CameraVideoCapturer cameraVideoCapturer;
         private final CameraEnumerationAndroid.CaptureFormat captureFormat;
         private final Set<String> availableCameras;
+        private boolean isFrontCamera = false;
 
         CapturerChoice(CameraVideoCapturer cameraVideoCapturer, CameraEnumerationAndroid.CaptureFormat captureFormat, Set<String> cameras) {
             this.cameraVideoCapturer = cameraVideoCapturer;