add LoadingScreen and TextureAtlas asset support

core/src/main/java/io/github/com/quillraven/GdxGame.java

@@ -15,6 +15,7 @@ import com.badlogic.gdx.utils.viewport.FitViewport;
 import com.badlogic.gdx.utils.viewport.Viewport;
 import io.github.com.quillraven.asset.AssetService;
 import io.github.com.quillraven.screen.GameScreen;
+import io.github.com.quillraven.screen.LoadingScreen;
 
 import java.util.HashMap;
 
@@ -43,8 +44,8 @@ public class GdxGame extends Game {
         glProfiler = new GLProfiler(Gdx.graphics);
         glProfiler.enable();
 
-        addScreen(new GameScreen(this));
-        setScreen(GameScreen.class);
+        addScreen(new LoadingScreen(this));
+        setScreen(LoadingScreen.class);
     }
 
     public void addScreen(Screen screen) {

core/src/main/java/io/github/com/quillraven/asset/AssetService.java

@@ -3,6 +3,7 @@ package io.github.com.quillraven.asset;
 import com.badlogic.gdx.Gdx;
 import com.badlogic.gdx.assets.AssetManager;
 import com.badlogic.gdx.assets.loaders.FileHandleResolver;
+import com.badlogic.gdx.graphics.g2d.TextureAtlas;
 import com.badlogic.gdx.maps.tiled.TiledMap;
 import com.badlogic.gdx.maps.tiled.TmxMapLoader;
 import com.badlogic.gdx.utils.Disposable;
@@ -16,9 +17,10 @@ public class AssetService implements Disposable {
     }
 
     public TiledMap load(MapAsset mapAsset) {
-        this.assetManager.load(mapAsset.getPath(), TiledMap.class);
+        String path = mapAsset.getPath();
+        this.assetManager.load(path, TiledMap.class);
         this.assetManager.finishLoading();
-        return this.assetManager.get(mapAsset.getPath(), TiledMap.class);
+        return this.assetManager.get(path, TiledMap.class);
     }
 
     public void unload(MapAsset mapAsset) {
@@ -26,6 +28,14 @@ public class AssetService implements Disposable {
         this.assetManager.finishLoading();
     }
 
+    public void queue(AtlasAsset atlasAsset) {
+        this.assetManager.load(atlasAsset.getPath(), TextureAtlas.class);
+    }
+
+    public boolean update() {
+        return this.assetManager.update();
+    }
+
     public void debugDiagnostics() {
         Gdx.app.debug("AssetService", this.assetManager.getDiagnostics());
     }

core/src/main/java/io/github/com/quillraven/asset/AtlasAsset.java

@@ -0,0 +1,15 @@
+package io.github.com.quillraven.asset;
+
+public enum AtlasAsset {
+    OBJECTS("objects.atlas");
+
+    private final String path;
+
+    AtlasAsset(String atlasName) {
+        this.path = "graphics/" + atlasName;
+    }
+
+    public String getPath() {
+        return path;
+    }
+}

core/src/main/java/io/github/com/quillraven/screen/LoadingScreen.java

@@ -0,0 +1,40 @@
+package io.github.com.quillraven.screen;
+
+import com.badlogic.gdx.Gdx;
+import com.badlogic.gdx.ScreenAdapter;
+import io.github.com.quillraven.GdxGame;
+import io.github.com.quillraven.asset.AssetService;
+import io.github.com.quillraven.asset.AtlasAsset;
+
+public class LoadingScreen extends ScreenAdapter {
+
+    private final GdxGame game;
+    private final AssetService assetService;
+
+    public LoadingScreen(GdxGame game) {
+        this.game = game;
+        this.assetService = game.getAssetService();
+    }
+
+    @Override
+    public void show() {
+        for (AtlasAsset atlasAsset : AtlasAsset.values()) {
+            assetService.queue(atlasAsset);
+        }
+    }
+
+    @Override
+    public void render(float delta) {
+        if (assetService.update()) {
+            Gdx.app.debug("LoadingScreen", "Finished loading assets");
+            createScreens();
+            this.game.removeScreen(this);
+            this.dispose();
+            this.game.setScreen(GameScreen.class);
+        }
+    }
+
+    private void createScreens() {
+        this.game.addScreen(new GameScreen(this.game));
+    }
+}