Add fade out/in transition between screens

core/src/io/github/lonamiwebs/klooni/Klooni.java

@@ -4,12 +4,14 @@ import com.badlogic.gdx.Application;
 import com.badlogic.gdx.Game;
 import com.badlogic.gdx.Gdx;
 import com.badlogic.gdx.Preferences;
+import com.badlogic.gdx.Screen;
 import com.badlogic.gdx.graphics.Texture;
 import com.badlogic.gdx.graphics.g2d.BitmapFont;
 import com.badlogic.gdx.graphics.g2d.NinePatch;
 import com.badlogic.gdx.scenes.scene2d.ui.Skin;
 
 import io.github.lonamiwebs.klooni.screens.MainMenuScreen;
+import io.github.lonamiwebs.klooni.screens.TransitionScreen;
 
 public class Klooni extends Game {
 
@@ -82,6 +84,15 @@ public class Klooni extends Game {
         super.render();
     }
 
+    // TransitionScreen will also dispose by default the previous screen
+    public void transitionTo(Screen screen) {
+        transitionTo(screen, true);
+    }
+
+    public void transitionTo(Screen screen, boolean disposeAfter) {
+        setScreen(new TransitionScreen(this, getScreen(), screen, disposeAfter));
+    }
+
     //endregion
 
     //region Disposing

core/src/io/github/lonamiwebs/klooni/screens/CustomizeScreen.java

@@ -145,8 +145,7 @@ class CustomizeScreen implements Screen {
     //region Private methods
 
     private void goBack() {
-        CustomizeScreen.this.game.setScreen(lastScreen);
-        dispose();
+        CustomizeScreen.this.game.transitionTo(lastScreen);
     }
 
     //endregion

core/src/io/github/lonamiwebs/klooni/screens/MainMenuScreen.java

@@ -46,9 +46,8 @@ public class MainMenuScreen extends InputListener implements Screen {
                 0, GameScreen.hasSavedData() ? "play_saved_texture" : "play_texture");
         playButton.addListener(new ChangeListener() {
             public void changed (ChangeEvent event, Actor actor) {
-                MainMenuScreen.this.game.setScreen(
+                MainMenuScreen.this.game.transitionTo(
                         new GameScreen(MainMenuScreen.this.game, GameScreen.GAME_MODE_SCORE));
-                dispose();
             }
         });
         table.add(playButton).colspan(3).fill().space(16);
@@ -70,9 +69,8 @@ public class MainMenuScreen extends InputListener implements Screen {
         statsButton.addListener(new ChangeListener() {
             @Override
             public void changed(ChangeEvent event, Actor actor) {
-                MainMenuScreen.this.game.setScreen(
+                MainMenuScreen.this.game.transitionTo(
                         new GameScreen(MainMenuScreen.this.game, GameScreen.GAME_MODE_TIME));
-                dispose();
             }
         });
         table.add(statsButton).space(16);
@@ -81,8 +79,9 @@ public class MainMenuScreen extends InputListener implements Screen {
         final SoftButton paletteButton = new SoftButton(3, "palette_texture");
         paletteButton.addListener(new ChangeListener() {
             public void changed (ChangeEvent event, Actor actor) {
-                MainMenuScreen.this.game.setScreen(new CustomizeScreen(MainMenuScreen.this.game, MainMenuScreen.this.game.getScreen()));
                 // Don't dispose because then it needs to take us to the previous screen
+                MainMenuScreen.this.game.transitionTo(new CustomizeScreen(
+                        MainMenuScreen.this.game, MainMenuScreen.this.game.getScreen()), false);
             }
         });
         table.add(paletteButton).space(16);

core/src/io/github/lonamiwebs/klooni/screens/PauseMenuStage.java

@@ -59,8 +59,7 @@ class PauseMenuStage extends Stage {
 
         homeButton.addListener(new ChangeListener() {
             public void changed (ChangeEvent event, Actor actor) {
-                game.setScreen(new MainMenuScreen(game));
-                dispose();
+                game.transitionTo(new MainMenuScreen(game));
             }
         });
 
@@ -72,8 +71,7 @@ class PauseMenuStage extends Stage {
             @Override
             public void changed(ChangeEvent event, Actor actor) {
                 // false, don't load the saved game state; we do want to replay
-                game.setScreen(new GameScreen(game, gameMode, false));
-                dispose();
+                game.transitionTo(new GameScreen(game, gameMode, false));
             }
         });
 
@@ -86,8 +84,8 @@ class PauseMenuStage extends Stage {
         paletteButton.addListener(new ChangeListener() {
             @Override
             public void changed(ChangeEvent event, Actor actor) {
-                game.setScreen(new CustomizeScreen(game, game.getScreen()));
                 // Don't dispose because then it needs to take us to the previous screen
+                game.transitionTo(new CustomizeScreen(game, game.getScreen()), false);
             }
         });
 

core/src/io/github/lonamiwebs/klooni/screens/TransitionScreen.java

@@ -0,0 +1,141 @@
+package io.github.lonamiwebs.klooni.screens;
+
+import com.badlogic.gdx.Gdx;
+import com.badlogic.gdx.Screen;
+import com.badlogic.gdx.graphics.GL20;
+import com.badlogic.gdx.graphics.Pixmap;
+import com.badlogic.gdx.graphics.g2d.SpriteBatch;
+import com.badlogic.gdx.graphics.g2d.TextureRegion;
+import com.badlogic.gdx.graphics.glutils.FrameBuffer;
+
+import io.github.lonamiwebs.klooni.Klooni;
+
+public class TransitionScreen implements Screen {
+
+    //region Members
+
+    // Rendering
+    private FrameBuffer frameBuffer;
+    private TextureRegion bufferTexture;
+    private final SpriteBatch spriteBatch;
+    private float fadedElapsed;
+    private boolean fadingOut;
+    private int width, height;
+
+    // From, to, and game to change the screen after the transition finishes
+    private final Screen fromScreen, toScreen;
+    private final Klooni game;
+
+    // Should the previous screen be disposed afterwards? Not desirable
+    // if it was stored somewhere else, for example, to return to it later
+    private final boolean disposeAfter;
+
+    //endregion
+
+    //region Static variables
+
+    // Time it takes to fade out and in, 0.15s (0.3s total)
+    private static final float FADE_INVERSE_DELAY = 1f / 0.15f;
+
+    //endregion
+
+    //region Constructor
+
+    public TransitionScreen(Klooni game, Screen from, Screen to, boolean disposeAfter) {
+        this.disposeAfter = disposeAfter;
+        this.game = game;
+        fromScreen = from;
+        toScreen = to;
+
+        spriteBatch = new SpriteBatch();
+    }
+
+    //endregion
+
+    //region Rendering
+
+    @Override
+    public void show() {
+        fadedElapsed = 0f;
+        fadingOut = true;
+    }
+
+    @Override
+    public void render(float delta) {
+        // Black background since we're fading to black
+        Gdx.gl.glClearColor(0, 0, 0, 1);
+        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
+
+        // Render on another buffer so then we can set its opacity. This
+        // second buffer also would allow us to do more stuff, since then
+        // we can use a texture, which we could move across the screen.
+        frameBuffer.begin();
+
+        float opacity;
+        if (fadingOut) {
+            fromScreen.render(delta);
+            opacity = 1 - Math.min(fadedElapsed * FADE_INVERSE_DELAY, 1);
+            if (opacity == 0) {
+                fadedElapsed = 0;
+                fadingOut = false;
+            }
+        }
+        else {
+            toScreen.render(delta);
+            opacity = Math.min(fadedElapsed * FADE_INVERSE_DELAY, 1);
+        }
+
+        frameBuffer.end();
+
+        // Render the faded texture
+        spriteBatch.begin();
+        spriteBatch.setColor(1, 1, 1, opacity);
+        spriteBatch.draw(bufferTexture, 0, 0, width, height);
+        spriteBatch.end();
+        fadedElapsed += delta;
+
+        // We might have finished fading if the opacity is full
+        if (opacity == 1 && !fadingOut) {
+            game.setScreen(toScreen);
+            dispose();
+        }
+    }
+
+    @Override
+    public void resize(int width, int height) {
+        this.width = width;
+        this.height = height;
+        if (frameBuffer != null)
+            frameBuffer.dispose();
+
+        frameBuffer = new FrameBuffer(Pixmap.Format.RGB565, width, height, false);
+        bufferTexture = new TextureRegion(frameBuffer.getColorBufferTexture());
+        bufferTexture.flip(false, true);
+    }
+
+    //endregion
+
+    //region Disposing
+
+    @Override
+    public void dispose() {
+        frameBuffer.dispose();
+        if (disposeAfter)
+            fromScreen.dispose();
+    }
+
+    //endregion
+
+    //region Unused methods
+
+    @Override
+    public void pause() { }
+
+    @Override
+    public void resume() { }
+
+    @Override
+    public void hide() { }
+
+    //endregion
+}