feinorgh / LM-Engine

"The Vim of game engines"

LM Engine

Made with EnTT and Bullet Physics.

Currently builds on Linux and Windows.

This is very work-in-progress. It exists now primarily as an example of how to construct an engine with the stated design goals.

Design Goals

Keyboard Centric

Every action the editor can perform is accessible through a keyboard shortcut. Pressing F1 shows the list of currently accessible actions and their shortcuts. Users should not need to take their hands off the keyboard.

Plain Text Assets

File formats for assets like maps and archetypes (prefabs) are human-readable with minimal noise. There are no GUIDs that change with every save of the asset. There is only plain, meaningful data.

This makes assets first-class citizens in source code management tools like git. They can be merged and have conflicts resolved like source code.

All Changes Saved

Instead of the user deciding when to save an asset, LM-Engine saves all changes as they are made. The user is expected to utilise version control to protect data they don't want overwritten.

Data Oriented

The core API for game logic is based on entity-component-system. Mutation of game state is done through plain-old-data instead of interface methods and classes.

Modules

lmpl

Platform/windowing system abstraction library.

lmgl

Graphics Library implemented with Vulkan.

lmlib

C++ utility library.

lmtk

GUI app toolkit built on top of lmpl and lmgl.

lmng

Core game logic and simulation library.

lmeditor

Game asset creation application.

lmhuv

Presentation layer library. Separates core game logic from graphics/sound.

sample

Example 3D game made with the engine.

Requirements

• Python 3
• The Conan package manager
• CMake
• Vulkan graphics drivers
• Linux
  • Redhat/Fedora
    • libwayland-dev
    • libx11-xcb-dev
    • libxcb-randr0-dev
    • libxcb-util0-dev
    • pkg-config
    • libgtkmm-3.0-dev
    • vulkan-validation-layers

Setup

On the command line, in the repository root directory, run:

• This may override your Conan config. If you need to keep your config, set the environment variable CONAN_USER_HOME to a directory of your choice while running these commands.
• conan profile update settings.compiler.libcxx=libstdc++11 default
• conan config install conan/config/common
• mkdir build && conan install . -if build --build missing

You may now run a regular CMake config/build in the build directory. See documentation of CMake and Conan for using different configurations/settings.

Running the Editor

Run the Editor executable in the build bin directory with the --project-dir argument set to the sample project directory eg.

• cd build/bin
• ./Editor --project-dir ../../sample.
  • Editor.exe --project-dir ../../sample on Windows

Adding Projects

To create your own project, create a directory in a projects subdirectory in the repository root. As a starting point, copy the sample directory contents there and rename the CMake targets in CMakeLists.txt.

Packaging Standalone Builds

To create a separate directory containing just what's needed to run a game (assets and binaries), use the LM_PACKAGE CMake macro (as seen in sample/CMakeLists.txt), then run:

• cmake --install <cmake_build_directory> --component <game_target_name>_package --prefix <chosen_output_dir>