doomgeneric interop fork

This doomgeneric fork is focused on embedding Doom into managed hosts through callbacks. Feel free to read the original repo's README for more information on doomgeneric.

How do I start?

Implement these callbacks in your host environment.

Function	Description	Notes
void Init(byte* screen_buffer, *int resX, int resY)	Initialize your platform (create window, framebuffer, etc...)
void DrawFrame()	Frame is ready in the screen buffer (given to you in Init). Copy it to your platform's screen.	You may need to flip your screen depending on your renderer.
void Sleep(uint32 millis)	Sleep in milliseconds, then return.	You may want to run the Doom loop in a separate thread so you can suspend it without affecting the rest of your application.
uint32 GetTicksMillis()	Milliseconds elapsed since a fixed point (e.g. launch).
bool GetKey(out bool* pressed, out char* key)	Provide keyboard events.	If there's a new key press/release event to process, assign the pressed (true for down, false for up) and key (DOOMKEY or ASCII character) values and return true.
void GetMouse(out int* deltaX, out int* deltaY, out bool* left, out bool* right, out bool* middle, out int* wheelDelta)	Optional. Provide mouse input.	deltaX/deltaY should be the change in pointer location since the last call to GetMouse; left, right, and middle are the current state of the mouse buttons (true if pressed down); wheelDelta is the mouse wheel change since last call to GetMouse (negative for scrolling down).
void SetWindowTitle(char* title)	Optional. This is for setting the window title as Doom sets this from WAD file.
void Exit(int exit_code)	Called when Doom wants to exit.	You're free to close your app when this is called, or ignore it and continue running - though, keep in mind that continuing to run after a non-zero exit_code may not end well for your application.
void Log(char* message)	Optional. Helper for native debugging.	Most likely nothing will call this, so it's safe to omit.

How do I run it in my host application?

Create an object that contains the above callbacks. Make sure they are ordered exactly as the table above shows. You may need to prevent your compiler/runtime from arbitrarily reordering members (C# example). Replace optional callbacks you don't want to implement with NULL pointers.

First, call SetCallbacks with a pointer to your callbacks object. If your host is managed, you must pin the object and all callback function pointers to prevent the garbage collector from moving/collecting them.

When you want to start the game, call Create.

Then, call Tick in a loop. You should probably do this on a dedicated thread, as the native side will call your Sleep(uint32 millis) callback expecting you to return after that time has passed (i.e. the game expects you to put the thread to sleep for that time).

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For an example implementation, see the proof-of-concept C# library. There's also an Avalonia-based player available (which uses that library) as an example starting point for a UI application.

Sound?

Define FEATURE_SOUND before you compile the native dll. Then, on the managed host, call SetAudioCallbacks with your sound/music callbacks before Create.

Sound effect data sent to callbacks is in mono 16-bit signed PCM (expanded from 8-bit unsigned PCM). Note that there are 32 bytes (16 samples) of padding before the sound data actually starts. Most sound effects are in 11025hz, but you should follow the sample rate you're given just in case.

Music is sent to callbacks as MIDI (converted internally from MUS).

Other features? (jumping, rebinding controls, modern rendering, etc.)

This is a very limited-scope project for me (I just wanted to get Doom running inside a Unity mod) but if you get it working let me know! I love to see the concept of "Doom on everything" thrive.

Platforms

This fork has only been tested on Windows.