Add support for Alt+Enter toggling fullscreen

src/main/java/be/seeseemelk/diceos/system/DisplayService.java

@@ -1,5 +1,6 @@
 package be.seeseemelk.diceos.system;
 
+import com.badlogic.gdx.Gdx;
 import com.badlogic.gdx.graphics.Pixmap;
 import com.badlogic.gdx.graphics.Texture;
 import com.badlogic.gdx.graphics.g2d.SpriteBatch;
@@ -26,6 +27,14 @@ public class DisplayService implements OnStartup {
         batch = new SpriteBatch();
     }
 
+    public void toggleFullscreen() {
+        if (Gdx.graphics.isFullscreen()) {
+            Gdx.graphics.setWindowedMode(getWidth(), getHeight());
+        } else {
+            Gdx.graphics.setFullscreenMode(Gdx.graphics.getDisplayMode());
+        }
+    }
+
     public int getWidth() {
         return 640;
     }

src/main/java/be/seeseemelk/diceos/system/InputService.java

@@ -0,0 +1,36 @@
+package be.seeseemelk.diceos;
+
+import be.seeseemelk.diceos.system.DisplayService;
+import be.seeseemelk.diceos.system.OnStartup;
+import com.badlogic.gdx.Gdx;
+import com.badlogic.gdx.Input;
+import com.badlogic.gdx.InputAdapter;
+import io.avaje.inject.Component;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+
+@Slf4j
+@Component
+@RequiredArgsConstructor
+public class InputService implements OnStartup {
+    private final DisplayService displayService;
+
+    @Override
+    public void onStartup() {
+        Gdx.input.setInputProcessor(new InputAdapter() {
+            @Override
+            public boolean keyDown(int keycode) {
+                log.info("Key pressed: {}", keycode);
+                if (keycode == Input.Keys.ENTER && isAltDown()) {
+                    displayService.toggleFullscreen();
+                }
+                return false;
+            }
+        });
+    }
+
+    public boolean isAltDown() {
+        return Gdx.input.isKeyPressed(com.badlogic.gdx.Input.Keys.ALT_LEFT) ||
+               Gdx.input.isKeyPressed(com.badlogic.gdx.Input.Keys.ALT_RIGHT);
+    }
+}