Editing Eternity Engine (section)

===Playing Eternity===
When run directly, Eternity tries to find the DOOM, DOOM 2 or Final DOOM megawads in some standard locations. If it can't find them, it will let you know. If it finds several of them, it will start with a picker screen, letting you choose.

On [[Wikipedia:Windows|Windows]] you can use the drag-and-drop feature of Explorer by moving WADs and PKEs into Eternity's executable. Or you can use Powershell or Command Prompt in a manner similar to starting [[Doom Wiki:Vanilla Doom|vanilla DOOM]]. See [[list of command line parameters]]. For more advanced cases, you can use [[GFS]] files to quickly load multiple files and settings together.

The [[Wikipedia:macOS|macOS]] version of Eternity also comes with a visual dialog-box launcher, hiding the complexity behind starting a terminal.

For advanced technical stuff, cheating and testing maps, Eternity has a [[console]] similar to [[Wikipedia:Quake|Quake's]].

====Loading main game WADs====
Eternity looks for the main game WADs (IWADs), e.g. doom2.wad, at these locations:
* IWAD file paths in user/system.cfg;
* the -iwad command-line parameter;
* the [[Doom Wiki:Environment variables|'''DOOMWADDIR''' or '''DOOMWADPATH''' environment variables]];
* the IWAD in the working directory;
* the IWAD file under the appropriate game folder of the base directory, which can be found using the -game parameter.

====Loading Master Levels for DOOM II====
Eternity offers a menu for conveniently loading each WAD from the Master Levels. To start the Master Levels:
# Start Eternity with DOOM II;
# Go to the Options menu, under the Game Files section, select WAD Options;
# Under the Master Levels section, you may need to specify Master Levels Dir to the path with the WADs;
# Once the path is configured, enter Play Master Levels.
Once the Master Levels Dir is configured, entering New Game from the menu will give you the choice to start the Master Levels.