Eternity

Mutlithreaded Java 2D Game Engine. Available under the MIT License.

Eternity is a java soft 2d game engine and requires Java 8 or above. It is written in pure java and is tested under windows 7 and linux(fedora 24).

It uses the luaj library which is available under the MIT License to allow for a fully scriptable game. In fact it is the preffered way to create a game.

• http://www.luaj.org/luaj/3.0/README.html#1

The engine also uses toml4j and gson which are available under the MIT License and the Apache License Version 2.0 respectively.

• https://github.com/mwanji/toml4j
• https://github.com/google/gson

#TOML See: https://github.com/toml-lang/toml for more information about TOML. To be able to read TOML files in lua it is recomended to use a modified verision of lua-toml (available under the Happy License) which is itself available under the Happy License.

• original: https://github.com/jonstoler/lua-toml
• modified: https://github.com/The127/eternity-toml-lua

#Features Engine

• fully java implementation
• 2 step multithreaded renering pipeline
• highly optimised 2d graphics rendering code (no hardware rendering)
• Tiled map editor json export support
• standard launcher implementation (with swing and awt components)
• readable TOML file format for settings and config files

Graphics

• highly optimised 2D rendering algorithms
• portable rendering engine (not tied to swing or awt)
• lightweight text rendering implementation

Map and tiles

• automatic tileset slicing
• automatic map loading
• local tile id conversion

Scripting

• lua scripting
• fully scriptable
• engine methods exposed to lua
• automatic script loading

Audio

• positional audio effect

#Java The java programming part can be as easy as to create a java project, incluse the eternity engine and luaj.jar. Then write the following code:

import java.io.IOException;

import de.eternity.Launcher;

public class Main {

	public static void main(String[] args) throws IOException {
		
		Launcher.initGame("Display Title");
		//add your java-lua functions here
		Launcher.start("start_game_state_name");
	}
}

The rest may be implemented in lua.

#Scripting The following lua functions are available.

Input Methods

poll_input() : void

• Must be called in every update cycle exactly once at the beginning if keyboard and/or mouse input is needed.

  get_mouse_position() : int, int

• Returns first the x and second the y position of the mouse.

  is_mouse_pressed(int buttonCode) : boolean

• Returns true if the button is pressed, false otherwise.

• All button codes are available as a variable BUTTON(number(1-3))

  is_key_pressed(int keyCode) : boolean

• Returns true if the button is pressed, false otherwise.

• All key codes are available as a variable VK_keyname

Game State Methods

push_game_state(string gameStateName) : void

• This method pushes another game state on the stack.

• The parameter gameStateName is the name of the lua file for the game state.

  pop_game_state() : void

• This method pops the current game state off the stack.

Utility Methods

get_data_file_path(string fileName) : string

• This method returns the path to the file.

  get_game_data() : GameData

• This method returns the game data object of the game.

• This object is sometimes needed as a parameter.

• This object provides access to the game data.

  get_fps() : int

• This method returns the current fps of the game.

• The fps is only updated each second and therefore is 0 in the first second.

Map Methods

get_game_map(string name) : GameMap

• This method returns the game map the the given name.

Graphics Methods

new_text_line(string text, int color): Text

• Returns a new drawable text.

  new_text_area(int chars_horizontal, int chars_vertical, int color): Text

• Returns a new drawable text with the specified area.

• This Text object does not yet contain any data.

  set_window_title(string title) : void

• This method sets the title of the game window.

  argb_to_color(int a, int r, int g, int b): int

• This method returns a single integer from the single argb color parts.

  rgb_to_color( int r, int g, int b): int

• This method returns a single integer from the single rgb color parts (full alpha).

  load_animation(string animation) : Animation

• This method loads a local animation file and returns a translated animation object.

  udpate_tile_animations(double delta) : void

• This method should be called once every update cycle.

• This method updates the tile animations (as the name suggests).

  get_textute_storage() : void

• This method returns the global texture storage.

  to_global_texture_id(string tileset, int localId) : int

• This method returns the global texture id of the local texture id of the tileset.

Sound Methods

load_sound(string sound) : Sound

• This method loads a sound file into a sound instance.
• Be aware that sound objects are big and leave a lot of garbage for the gc.
• See Sound class documentation for more methods and information.