Fix for jMonkeyEngine#2327 Mouse pointer moves to centre of canvas on…

… click in OpenGL3 with Swing

Modify FlyByCamera to only hide the mouse cursor when the user actually rotates the camera, rather than when the user first presses the left mouse button.
When the mouse is clicked, instead of immediately hiding the cursor, a flag (hideCursorOnNextRotate) is set. If and when a rotate is detected, the flag is checked and if true the cursor is hidden and the flag is cleared.

jme3-core/src/main/java/com/jme3/input/FlyByCamera.java

@@ -107,6 +107,7 @@ public class FlyByCamera implements AnalogListener, ActionListener {
     protected boolean dragToRotate = false;
     protected boolean canRotate = false;
     protected boolean invertY = false;
+    private boolean hideCursorOnNextRotate = false;
     protected InputManager inputManager;
 
     /**
@@ -200,6 +201,7 @@ public void setEnabled(boolean enable){
         if (enabled && !enable){
             if (inputManager!= null && (!dragToRotate || (dragToRotate && canRotate))){
                 inputManager.setCursorVisible(true);
+                hideCursorOnNextRotate = false;
             }
         }
         enabled = enable;
@@ -353,6 +355,10 @@ public void unregisterInput() {
     protected void rotateCamera(float value, Vector3f axis) {
         if (dragToRotate) {
             if (canRotate) {
+                if(hideCursorOnNextRotate) {
+                    inputManager.setCursorVisible(false);
+                    hideCursorOnNextRotate = false;
+                }
 //                value = -value;
             } else {
                 return;
@@ -499,7 +505,14 @@ public void onAction(String name, boolean value, float tpf) {
 
         if (name.equals(CameraInput.FLYCAM_ROTATEDRAG) && dragToRotate) {
             canRotate = value;
-            inputManager.setCursorVisible(!value);
+
+            if(value) {
+                hideCursorOnNextRotate = true;
+            }
+            else {
+                inputManager.setCursorVisible(true);
+                hideCursorOnNextRotate = false;
+            }
         } else if (name.equals(CameraInput.FLYCAM_INVERTY)) {
             // Invert the "up" direction.
             if (!value) {