Merge pull request #1087 from jayfella/master

Add support for listening to joystick connection/disconnection.

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

@@ -0,0 +1,21 @@
+package com.jme3.input;
+
+/**
+ * Listens for the state of a joystick connection.
+ * @author jayfella
+ */
+public interface JoystickConnectionListener {
+
+    /**
+     * Occurs when a new joystick has been detected.
+     * @param joystick the joystick that has been detected.
+     */
+    void onConnected(Joystick joystick);
+
+    /**
+     * Occurs when an existing joystick has been disconnected.
+     * @param joystick the joystick that has been disconnected.
+     */
+    void onDisconnected(Joystick joystick);
+
+}

jme3-lwjgl3/src/main/java/com/jme3/input/lwjgl/GlfwJoystickInput.java

@@ -49,7 +49,7 @@ import static org.lwjgl.glfw.GLFW.*;
  */
 public class GlfwJoystickInput implements JoyInput {
 
-    private static final Logger LOGGER = Logger.getLogger(InputManager.class.getName());
+    private static final Logger LOGGER = Logger.getLogger(GlfwJoystickInput.class.getName());
 
     private RawInputListener listener;
 
@@ -66,8 +66,28 @@ public class GlfwJoystickInput implements JoyInput {
         }
     }
 
+    public void fireJoystickConnectedEvent(int jid) {
+        Joystick joystick = joysticks.get(jid);
+        ((InputManager)listener).fireJoystickConnectedEvent(joystick);
+    }
+
+    public void fireJoystickDisconnectedEvent(int jid) {
+        Joystick joystick = joysticks.get(jid);
+        ((InputManager)listener).fireJoystickDisconnectedEvent(joystick);
+    }
+
+    public void reloadJoysticks() {
+        joysticks.clear();
+
+        InputManager inputManager = (InputManager) listener;
+
+        Joystick[] joysticks = loadJoysticks(inputManager);
+        inputManager.setJoysticks(joysticks);
+    }
+
     @Override
     public Joystick[] loadJoysticks(final InputManager inputManager) {
+
         for (int i = 0; i < GLFW_JOYSTICK_LAST; i++) {
             if (glfwJoystickPresent(i)) {
                 final String name = glfwGetJoystickName(i);
@@ -126,23 +146,33 @@ public class GlfwJoystickInput implements JoyInput {
     @Override
     public void update() {
         for (final Map.Entry<Integer, GlfwJoystick> entry : joysticks.entrySet()) {
+
             // Axes
             final FloatBuffer axisValues = glfwGetJoystickAxes(entry.getKey());
 
-            for (final JoystickAxis axis : entry.getValue().getAxes()) {
-                final float value = axisValues.get(axis.getAxisId());
-                listener.onJoyAxisEvent(new JoyAxisEvent(axis, value));
+            // if a joystick is added or removed, the callback reloads the joysticks.
+            // when the callback is called and reloads the joystick, this iterator may already have started iterating.
+            // To avoid a NullPointerException we null-check the axisValues and bytebuffer objects.
+            // If the joystick it's iterating over no-longer exists it will return null.
+
+            if (axisValues != null) {
+                for (final JoystickAxis axis : entry.getValue().getAxes()) {
+                    final float value = axisValues.get(axis.getAxisId());
+                    listener.onJoyAxisEvent(new JoyAxisEvent(axis, value));
+                }
             }
 
             // Buttons
             final ByteBuffer byteBuffer = glfwGetJoystickButtons(entry.getKey());
 
-            for (final JoystickButton button : entry.getValue().getButtons()) {
-                final boolean pressed = byteBuffer.get(button.getButtonId()) == GLFW_PRESS;
+            if (byteBuffer != null) {
+                for (final JoystickButton button : entry.getValue().getButtons()) {
+                    final boolean pressed = byteBuffer.get(button.getButtonId()) == GLFW_PRESS;
 
-                if (joyButtonPressed.get(button) != pressed) {
-                    joyButtonPressed.put(button, pressed);
-                    listener.onJoyButtonEvent(new JoyButtonEvent(button, pressed));
+                    if (joyButtonPressed.get(button) != pressed) {
+                        joyButtonPressed.put(button, pressed);
+                        listener.onJoyButtonEvent(new JoyButtonEvent(button, pressed));
+                    }
                 }
             }
         }

jme3-lwjgl3/src/main/java/com/jme3/system/lwjgl/LwjglContext.java

@@ -37,6 +37,7 @@ import static java.util.stream.Collectors.toSet;
 import static org.lwjgl.opencl.CL10.CL_CONTEXT_PLATFORM;
 import static org.lwjgl.opengl.GL.createCapabilities;
 import static org.lwjgl.opengl.GL11.glGetInteger;
+
 import com.jme3.input.lwjgl.GlfwJoystickInput;
 import com.jme3.input.lwjgl.GlfwKeyInput;
 import com.jme3.input.lwjgl.GlfwMouseInput;
@@ -65,6 +66,7 @@ import com.jme3.util.LWJGLBufferAllocator.ConcurrentLWJGLBufferAllocator;
 import org.lwjgl.PointerBuffer;
 import org.lwjgl.Version;
 import org.lwjgl.glfw.GLFW;
+import org.lwjgl.glfw.GLFWJoystickCallback;
 import org.lwjgl.opencl.APPLEGLSharing;
 import org.lwjgl.opencl.CL10;
 import org.lwjgl.opencl.KHRGLSharing;
@@ -233,6 +235,24 @@ public abstract class LwjglContext implements JmeContext {
             joyInput.initialize();
         }
 
+        GLFW.glfwSetJoystickCallback(new GLFWJoystickCallback() {
+            @Override
+            public void invoke(int jid, int event) {
+
+                // Invoke the disconnected event before we reload the joysticks or we lose the reference to it.
+                // Invoke the connected event after we reload the joysticks to obtain the reference to it.
+
+                if ( event == GLFW.GLFW_CONNECTED ) {
+                    joyInput.reloadJoysticks();
+                    joyInput.fireJoystickConnectedEvent(jid);
+                }
+                else {
+                    joyInput.fireJoystickDisconnectedEvent(jid);
+                    joyInput.reloadJoysticks();
+                }
+            }
+        });
+
         renderable.set(true);
     }