doom-godot

Want to make your Godot game a bajillion times better? Add DOOM to it! This GDExtension allows you to do just that...

This repository structure is based on GDExtensionTemplate and is currently set up to work with the Godot 4.1 release. PureDOOM source port is used for the actual DOOM implementation, and is included as a submodule (see extern/puredoom).

Prerequisites

To use this locally on your machine, you will need the following:

• CMake v3.22+
• C++ Compiler with at least C++17 support (any recent compiler)
• (optional) ccache for faster rebuilds

Build

Here's an example of how to build a release version (use the terminal to run the following commands in the parent directory of this repo):

Not MSVC

cmake -B build -S . -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=doom-godot-install
cmake --build ./build --parallel

MSVC

cmake -B build -S . -G "Visual Studio 17 2022" -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=doom-godot-install
cmake --build ./build --config Release

This tells CMake to use Visual Studio 2022. There is a list of Visual Studio generators on the CMake site - pick the one you are using.

Cmake Options

The following additional CMake options are available:

Option	Description	Default
CCACHE_PROGRAM	Path to ccache for faster rebuilds	This is automatically set ON if ccache is found. If you do not want to use it, set this to "".
${PROJECT_NAME_UPPERCASE}_WARN_EVERYTHING (e.g. FOO_WARN_EVERYTHING)	Turns on all warnings. (Not available for MSVC.)	OFF (too noisy, but can be useful sometimes)
${PROJECT_NAME_UPPERCASE}_WARNING_AS_ERROR (e.g. FOO_WARNING_AS_ERROR)	Turns warnings into errors.	ON

Usage

1. Create a new GDScript, with the following content:

extends MeshInstance3D

func _ready():
	_init_doom()
	
var doom: Doom
var active = false

func _init_doom():
	if doom == null:
		doom = Doom.new()
		add_child(doom)
	doom.initialize()
	if self.material_override == null:
		self.material_override = StandardMaterial3D.new()
		self.material_override.shading_mode = BaseMaterial3D.SHADING_MODE_UNSHADED
	self.material_override.albedo_texture = ImageTexture.create_from_image(doom.get_framebuffer())

func check_key(godot_key, doom_key, key_is_pressed):
	if Input.is_key_pressed(godot_key):
		doom.key_down(doom_key)
	else:
		doom.key_up(doom_key)

func _unhandled_key_input(event):
	if event is InputEventKey:
		check_key(KEY_W, 173, event.is_pressed())
		check_key(KEY_A, 172, event.is_pressed())
		check_key(KEY_S, 175, event.is_pressed())
		check_key(KEY_D, 174, event.is_pressed())
		check_key(KEY_UP, 173, event.is_pressed())
		check_key(KEY_LEFT, 172, event.is_pressed())
		check_key(KEY_DOWN, 175, event.is_pressed())
		check_key(KEY_RIGHT, 174, event.is_pressed())
		check_key(KEY_SPACE, KEY_SPACE, event.is_pressed())
		check_key(KEY_CTRL, 157, event.is_pressed())
		check_key(KEY_ENTER, 13, event.is_pressed())
		check_key(KEY_ESCAPE, 27, event.is_pressed())

func _process(delta):
	if doom != null:
		doom.update()
		self.material_override.albedo_texture.set_image(doom.get_framebuffer())

2. Create a MeshInstance3D and attach the script to it!
3. Copy a DOOM IWAD to your project root folder, or instruct your end-users to copy such an IWAD to whatever your game's working directory is. Make sure the IWAD is named "DOOM.WAD". Users without a licensed copy of DOOM can use FreeDOOM, instead.