Resolve "Login screen setup (without backend)"

Closes #19 (closed)

frontend/core/src/com/game/tankwars/view/LoginScreen.java

+package com.game.tankwars.view;
+
+import com.badlogic.gdx.Gdx;
+import com.badlogic.gdx.Screen;
+import com.badlogic.gdx.graphics.Color;
+import com.badlogic.gdx.graphics.g2d.BitmapFont;
+import com.badlogic.gdx.graphics.g2d.SpriteBatch;
+import com.badlogic.gdx.scenes.scene2d.Actor;
+import com.badlogic.gdx.scenes.scene2d.Event;
+import com.badlogic.gdx.scenes.scene2d.InputEvent;
+import com.badlogic.gdx.scenes.scene2d.InputListener;
+import com.badlogic.gdx.scenes.scene2d.Stage;
+import com.badlogic.gdx.scenes.scene2d.ui.Button;
+import com.badlogic.gdx.scenes.scene2d.ui.Label;
+import com.badlogic.gdx.scenes.scene2d.ui.Skin;
+import com.badlogic.gdx.scenes.scene2d.ui.Table;
+import com.badlogic.gdx.scenes.scene2d.ui.TextButton;
+import com.badlogic.gdx.scenes.scene2d.ui.Image;
+import com.badlogic.gdx.scenes.scene2d.ui.TextField;
+import com.badlogic.gdx.scenes.scene2d.ui.Value;
+import com.badlogic.gdx.scenes.scene2d.utils.ChangeListener;
+import com.badlogic.gdx.scenes.scene2d.utils.Drawable;
+import com.badlogic.gdx.scenes.scene2d.utils.FocusListener;
+import com.badlogic.gdx.utils.Align;
+import com.badlogic.gdx.utils.ScreenUtils;
+import com.badlogic.gdx.utils.viewport.ExtendViewport;
+import com.game.tankwars.ResourceManager;
+import com.game.tankwars.TankWarsGame;
+import com.game.tankwars.controller.LoginController;
+
+
+/**
+ * Basic login screen with only a username text field.
+ * The user is logged in with the provided name when the login button
+ * is touched.
+ */
+public class LoginScreen implements Screen {
+    private final TankWarsGame tankWarsGame;
+    private Stage stage;
+    private TextField usernameField;
+
+    public LoginScreen(final TankWarsGame tankWarsGame) {
+        this.tankWarsGame = tankWarsGame;
+    }
+
+    @Override
+    public void show() {
+        stage = new Stage(new ExtendViewport(320, 240), new SpriteBatch());
+        Gdx.input.setInputProcessor(stage);
+
+        Skin skin = ResourceManager.getInstance().loadAndGetMenuAssets();
+
+        // TODO: Transition to ErrorScreen if skin == null
+
+        Image backgroundPortrait = new Image(skin.getDrawable("camo-background-portrait"));
+        Drawable backgroundBlurred = skin.getDrawable("camo-background-portrait-blurred");
+        Image logo = new Image(skin.getDrawable("logo"));
+        Drawable headerBox = skin.getDrawable("dark-menu-header");
+
+        Label loginLabel = new Label("Log in", skin.get("header", Label.LabelStyle.class));
+        Label usernameLabel = new Label("Username", skin.get("default", Label.LabelStyle.class));
+
+        usernameField = new TextField("",
+                        skin.get("default", TextField.TextFieldStyle.class));
+        usernameField.setAlignment(Align.center);
+        TextButton loginButton = new TextButton("Log in",
+                skin.get("default", TextButton.TextButtonStyle.class));
+
+        //--- Layout
+        float lw = 2 * stage.getWidth() / 5f;
+        float rw = stage.getWidth() - lw;
+
+        Table rootTable = new Table();
+        rootTable.setFillParent(true);
+        rootTable.center();
+        rootTable.add(backgroundPortrait).width(lw).
+                left().minHeight(stage.getHeight()).
+                height(backgroundPortrait.getHeight() / backgroundPortrait.getWidth() * lw);
+
+        Table rightTable = new Table();
+        rightTable.background(backgroundBlurred);
+
+        Table headerTable = new Table();
+        headerTable.background(headerBox);
+        headerTable.add(logo).expandX().width(3 * rw / 7f).
+                height(logo.getHeight() / logo.getWidth() * 3 * rw / 7f);
+        headerTable.add(loginLabel).expandX();
+
+        rightTable.add(headerTable).fillX().height(stage.getHeight() / 4f);
+        rightTable.row().expand(1, 1);
+        rightTable.add(usernameLabel).width(2 * rw / 3f).bottom().padLeft(10);
+        rightTable.row().expand(1, 0);
+        rightTable.add(usernameField).width(2 * rw / 3f).height(42).top();
+        rightTable.row().expand(1, 4);
+        rightTable.add(loginButton).width(2 * rw / 3f).height(28);
+
+        rootTable.add(rightTable).expandX().height(stage.getHeight());
+        stage.addActor(rootTable);
+
+        new LoginController(tankWarsGame, loginButton, usernameField, stage);
+    }
+
+    @Override
+    public void render(float delta) {
+        ScreenUtils.clear(0, 0, 0, 1);
+
+        stage.act(delta);
+        stage.draw();
+    }
+
+    @Override
+    public void resize(int width, int height) {
+        stage.getViewport().update(width, height);
+    }
+
+    @Override
+    public void pause() {
+
+    }
+
+    @Override
+    public void resume() {
+
+    }
+
+    @Override
+    public void hide() {
+        Gdx.input.setInputProcessor(null);
+    }
+
+
+    @Override
+    public void dispose() {
+        stage.dispose();
+    }
+
+
+}