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Developer Guide
The page aims to detail how to start developing in the Open Imperium Galactica project.
- 64 bit CPU/operating system and at least 4GB RAM recommended.
Download and install the latest Java Development Kit (JDK), version 8 or later. 64 bit recommended. I also recommend JDK 17 or later as it appears to perform better regarding both the game logic and the Swing 2D rendering.
Download and install the latest Eclipse Integrated Development Environment (IDE), version 4.22.0 as of now. The standard Eclipse IDE for Java Developers version is enough. 64 bit recommended.
The source files are hosted in a Git repository and no separate plugin is required for that. (It used to be hosted as an SVN back in the Google Code days which did require a separate plugin.)
The Eclipse-CS plugin is required to ensure the coding style in the project.
Checkout the project from https://github.com/akarnokd/open-ig.git into your workspace. You should now see the src, audio, data and other directories in the project.
git clone https://github.com/akarnokd/open-ig.git
To add the game videos, create a new directory named video in the project root. From the install folder, unzip all files with open-ig-video in their name. Once done, you should see the en, hu, generic, etc. subdirectories.
For the development, the style checking plugin needs to be setup and activated. To do so, right click on the project name in the project view, and chose Properties.
Locate the Checkstyle entry and on the right, chose Local Checkstyle Configurations tab. Here, click on New..., chose Project relative configuration from Type: dropdown, give it a name and click on Browse... and locate the checkstyle.xml inside the project root folder. Click OK buttons until you get back to the project properties dialog.
Now chose the main Main tab of the Checkstyle settings, and from the Simple - ... dropdown box, chose the name you specified before.
Click OK again, right click on the project root and chose Checkstyle > Activate Checkstyle.
The game's main entry point is the hu.openig.Startup class. Using Debug as Java application won't work properly unless you specify some JVM and application parameters.
First, run the class hu.openig.Startup and you should see the main menu pop up. Quit, then, select Debug configurations... from the debug icon's dropdown menu. Locate the Java Application node and a Startup below that which was just created.
On the right, switch to Arguments and enter -memonce into the Program arguments text field, and enter -Xmx1G into the VM arguments.
Now if you set a breakpoint in Startup.main, you should get the application stop there.
Note that the current requirements for the game is to run with 832MB Java memory. When doing code changes while debugging the game, that amount is usually inadequate, thus the 1GB. Generally, if you do developments that increase the memory consumption of the game, you should always test the game with the -Xmx832M settings.
This is a simple list of where things can be found in the source code. I'll omit the package names here. The CTRL+SHIFT+T in Eclipse lets you find the classes easily.
| Purpose | Classes |
|---|---|
| Game settings. | Configuration |
| Main entry point. | Startup |
| The game's main window. | GameWindow |
| Main rendering surface. | GameWindow.ScreenRenderer |
| General UI images and sound. | CommonResources, *GFX |
| Game main object | World |
| Interesting game world objects | Player, Planet, Fleet, InventoryItem, ResearchType |
| Game model objects | BuildingModel, PlanetSurface, BattleModel |
| Battle objects | SpacewarStructure, GroundwarUnit, GroundwarGun |
| Statusbar | StatusbarScreen |
| Various screens |
*Screen |
| Drawing text | TextRenderer |
| User interface | UIComponent, UIContainer, UIMouse, ScreenBase |
| General keyboard management | GameKeyManager |
| Game mechanics | Simulator, Radar |
| AI | AI, AITrader, AIPirate, AIUser, *Planner |
| Main campaign scripts | Mission*
|