Doomgeneric: Make Porting Doom Easier

The purpose of doomgeneric is to make porting Doom easier.
Of course Doom is already portable but with doomgeneric it is possible with just a few functions.

To try it you will need a WAD file (game data). If you don’t own the game, shareware version is freely available (doom1.wad).

Create a file named doomgeneric_yourplatform.c and just implement these functions to suit your platform.

DG_Init
DG_DrawFrame
DG_SleepMs
DG_GetTicksMs
DG_GetKey

Functions	Description
DG_Init	Initialize your platfrom (create window, framebuffer, etc…).
DG_DrawFrame	Frame is ready in DG_ScreenBuffer. Copy it to your platform’s screen.
DG_SleepMs	Sleep in milliseconds.
DG_GetTicksMs	The ticks passed since launch in milliseconds.
DG_GetKey	Provide keyboard events.
DG_SetWindowTitle	Not required. This is for setting the window title as Doom sets this from WAD file.

Sound is much harder to implement! If you need sound, take a look at SDL port. It fully supports sound and music! Where to start? Define FEATURE_SOUND, assign DG_sound_module and DG_music_module.

Ported platforms include Windows, X11, SDL, Soso. Just look at (doomgeneric_win.c or doomgeneric_xlib.c).