Add Lua scripting with a test script + code optimizations

Author: stringfromjava

assets/test.lua

@@ -0,0 +1,38 @@
+local Gdx = luajava.bindClass("com.badlogic.gdx.Gdx")
+local Input = luajava.bindClass("com.badlogic.gdx.Input")
+local Funkin = luajava.bindClass("me.stringfromjava.funkin.Funkin")
+local Paths = luajava.bindClass("me.stringfromjava.funkin.util.Paths")
+local Sprite = luajava.bindClass("com.badlogic.gdx.graphics.g2d.Sprite")
+local Texture = luajava.bindClass("com.badlogic.gdx.graphics.Texture")
+
+local TitleScreen = Funkin.screen
+
+local path = Paths:image('transitionSwag/stickers-set-1/bfSticker1')
+
+local new_sprite = Sprite.new(Texture.new(path))
+new_sprite:setPosition(100, 100)
+
+TitleScreen:add(new_sprite)
+
+local function onPostRender()
+    if Gdx.input:isKeyPressed(Input.Keys.W) then
+        new_sprite:setY(new_sprite:getY() + 10)
+    end
+    if Gdx.input:isKeyPressed(Input.Keys.A) then
+        new_sprite:setX(new_sprite:getX() - 10)
+    end
+    if Gdx.input:isKeyPressed(Input.Keys.S) then
+        new_sprite:setY(new_sprite:getY() - 10)
+    end
+    if Gdx.input:isKeyPressed(Input.Keys.D) then
+        new_sprite:setX(new_sprite:getX() + 10)
+    end
+end
+
+local runnable = luajava.createProxy('java.lang.Runnable', {
+    run = onPostRender
+})
+
+Funkin.Signals.postRender:add(runnable)
+
+Funkin:playSound('shared/sounds/ANGRY_TEXT_BOX.ogg')

core/build.gradle

@@ -9,6 +9,7 @@ dependencies {
   api "io.github.libktx:ktx-freetype:$ktxVersion"
   api "org.jetbrains.kotlin:kotlin-stdlib:$kotlinVersion"
   api "org.mini2Dx:universal-tween-engine:$universalTweenVersion"
+  implementation 'org.luaj:luaj-jse:3.0.1'
 
   if(enableGraalNative == 'true') {
     implementation "io.github.berstanio:gdx-svmhelper-annotations:$graalHelperVersion"

core/src/main/java/me/stringfromjava/funkin/Funkin.java

@@ -1,10 +1,10 @@
 package me.stringfromjava.funkin;
 
-import com.badlogic.gdx.Game;
 import com.badlogic.gdx.Gdx;
 import com.badlogic.gdx.audio.Music;
 import com.badlogic.gdx.audio.Sound;
 import me.stringfromjava.funkin.backend.display.FunkinScreen;
+import me.stringfromjava.funkin.lua.FunkinLua;
 import me.stringfromjava.funkin.tween.FunkinTween;
 import me.stringfromjava.funkin.util.FunkinSignal;
 import me.stringfromjava.funkin.util.Paths;
@@ -27,12 +27,6 @@ public final class Funkin {
      */
     public static FunkinScreen screen = null;
 
-    /**
-     * The static instance used to access the core elements of the game.
-     * This includes the loop, setting the current screen, and more.
-     */
-    public static Game game;
-
     /**
      * A map containing all sounds that are currently playing.
      * <p>
@@ -46,6 +40,17 @@ public final class Funkin {
      */
     public static Music music = null;
 
+    /**
+     * The global volume multiplier for all sounds and music.
+     */
+    public static float masterVolume = 1.0f;
+
+    /**
+     * The static instance used to access the core elements of the game.
+     * This includes the loop, setting the current screen, and more.
+     */
+    private static FunkinGame game;
+
     /**
      * Has the global manager been initialized yet?
      */
@@ -59,13 +64,14 @@ public final class Funkin {
      *
      * @param gameInstance The instance of the game to use.
      */
-    public static void initialize(Game gameInstance) {
+    public static void initialize(FunkinGame gameInstance) {
         if (initialized) {
             throw new IllegalStateException("FNF:JE has already been initialized!");
         }
         game = gameInstance;
 
         FunkinTween.registerAccessors();
+        FunkinLua.initialize();
 
         initialized = true;
     }
@@ -150,6 +156,15 @@ public static Music playMusic(String path, float volume, boolean looped) {
         return music;
     }
 
+    /**
+     * Gets the {@link FunkinGame} instance being used.
+     *
+     * @return The current {@code FunkinGame} instance.
+     */
+    public static FunkinGame getGame() {
+        return game;
+    }
+
     /**
      * Contains all the global events that get dispatched when something happens in the game.
      * <p>

core/src/main/java/me/stringfromjava/funkin/FunkinGame.java

@@ -32,6 +32,20 @@ public void render() {
         Funkin.Signals.postRender.dispatch();
     }
 
+    @Override
+    public void resume() {
+        super.resume();
+        Funkin.masterVolume = 1.0f;
+        Funkin.music.setVolume(1);
+    }
+
+    @Override
+    public void pause() {
+        super.pause();
+        Funkin.masterVolume = 0.008f;
+        Funkin.music.setVolume(0.008f);
+    }
+
     @Override
     public void dispose() {
         Funkin.Signals.preGameClose.dispatch();

core/src/main/java/me/stringfromjava/funkin/backend/display/FunkinScreen.java

@@ -42,7 +42,7 @@ public abstract class FunkinScreen implements Screen {
      */
     protected Color bgColor;
 
-    private final ArrayList<Sprite> sprites = new ArrayList<>();
+    public final ArrayList<Sprite> sprites = new ArrayList<>();
 
     @Override
     public void show() {

core/src/main/java/me/stringfromjava/funkin/game/menus/TitleScreen.java

@@ -1,8 +1,13 @@
 package me.stringfromjava.funkin.game.menus;
 
+import com.badlogic.gdx.Gdx;
+import com.badlogic.gdx.Input;
+import com.badlogic.gdx.graphics.Texture;
 import com.badlogic.gdx.graphics.g2d.Sprite;
 import me.stringfromjava.funkin.Funkin;
 import me.stringfromjava.funkin.backend.display.FunkinScreen;
+import me.stringfromjava.funkin.lua.FunkinLua;
+import me.stringfromjava.funkin.util.Paths;
 
 public class TitleScreen extends FunkinScreen {
 
@@ -11,7 +16,16 @@ public class TitleScreen extends FunkinScreen {
     @Override
     public void show() {
         super.show();
-        Funkin.playSound("shared/sounds/tickleFight.ogg");
+//        Funkin.playSound("shared/sounds/tickleFight.ogg");
         Funkin.playMusic("preload/music/freakyMenu/freakyMenu.ogg", 0.5f);
     }
+
+    @Override
+    public void render(float delta) {
+        super.render(delta);
+
+        if (Gdx.input.isKeyJustPressed(Input.Keys.SPACE)) {
+            FunkinLua.executeScript("test.lua");
+        }
+    }
 }

core/src/main/java/me/stringfromjava/funkin/lua/FunkinLua.java

@@ -0,0 +1,58 @@
+package me.stringfromjava.funkin.lua;
+
+import me.stringfromjava.funkin.lua.resource.FunkinLuaResourceFinder;
+import org.luaj.vm2.Globals;
+import org.luaj.vm2.LuaValue;
+import org.luaj.vm2.Varargs;
+import org.luaj.vm2.lib.jse.JsePlatform;
+
+/**
+ * Global manager and utility class for executing, manipulating and handling Lua scripts.
+ */
+public final class FunkinLua {
+
+    private static Globals globals;
+
+    /**
+     * Initializes the Lua global manager.
+     * <p>
+     * This must be called before any Lua scripts can be executed.
+     */
+    public static void initialize() {
+        globals = JsePlatform.standardGlobals();
+        globals.finder = new FunkinLuaResourceFinder();
+    }
+
+    /**
+     * Attempts to execute a Lua script located at the given path.
+     * If the script fails to run, then {@code LuaValue.NIL} is returned.
+     *
+     * @param path The path to the Lua script to execute.
+     * @return The result of the script execution, or {@code LuaValue.NIL} if it failed.
+     */
+    public static Varargs executeScript(String path) {
+        try {
+            LuaValue chunk = loadScript(path);
+
+            if (chunk.isfunction()) {
+                return chunk.invoke();
+            }
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+        return LuaValue.NIL;
+    }
+
+    public static LuaValue loadScript(String path) {
+        try {
+            LuaValue chunk = globals.loadfile(path);
+            return chunk;
+        } catch (Exception e) {
+            e.printStackTrace();
+            return LuaValue.NIL;
+        }
+    }
+
+    private FunkinLua() {
+    }
+}

core/src/main/java/me/stringfromjava/funkin/lua/resource/FunkinLuaResourceFinder.java

@@ -0,0 +1,28 @@
+package me.stringfromjava.funkin.lua.resource;
+
+import com.badlogic.gdx.Gdx;
+import com.badlogic.gdx.files.FileHandle;
+import org.luaj.vm2.lib.ResourceFinder;
+
+import java.io.InputStream;
+
+/**
+ * A resource finder for Lua scripts that looks for files
+ * in the internal assets of the game.
+ */
+public class FunkinLuaResourceFinder implements ResourceFinder {
+
+    @Override
+    public InputStream findResource(String filename) {
+        if (!filename.endsWith(".lua") && Gdx.files.internal(filename + ".lua").exists()) {
+            filename += ".lua";
+        }
+
+        FileHandle file = Gdx.files.internal(filename);
+        if (file.exists()) {
+            return file.read();
+        }
+
+        return null;
+    }
+}