A C++ game engine / Work-in-progress
The goal of this project is to implement a 3D game engine from scratch (within reason, I'm happy to use libraries for stuff like window creation or reading PNG files). I don't expect to use this for developing any actual games but rather treat it as a learning experience for graphics programming and C++ in general.
All external dependencies except for the OpenGL libraries are automatically downloaded and built using CMake. If your system does not include an OpenGL library, you will have to install it system-wide. The build system includes CMake presets for GCC and MSVC compilers. Simply opening the folder in CLion should take care of the pipeline setup, given that you define toolchains with the names gcc/msvc and enable the desired imported profiles. Builds using Visual Studio are not tested or maintained but there probably is an equivalent workflow.
The demo folder contains executable targets that showcase some aspects of the engine. To run an executable the working directory should be the corresponding demo folder. Running executables directly, i.e. outside of the IDE, may require copying the C++ standard libraries for the given compiler to the output directory.
The engine is built with a focus on modularity and thus includes various subsystems:
Templated library for linear algebra operations, including vectors, matrices, and quaternions, as well as common numeric operations required for graphics programming.
Platform abstraction layer (goto)
Platform specific operations like file handling, window creation, or input handling are abstracted into common interfaces, facilitating operation on desktop and android targets.
Graphics pipeline abstraction layer (goto)
The graphics pipeline has its own abstraction layer with high-level interfaces for common graphics objects, like shaders, textures, and drawable vertices. The focus is to provide implementations for OpenGL for desktop and OpenGL-ES for Android. Note that the OpenGL-ES implementations are severly outdated. Since the goal for the future is to also support Vulkan, the graphics interfaces will have to be redesigned from scratch anyway, so there is no use in updating the OpenGL-ES implementations now.
Handles image file reading/writing and provides a common representation for image data on the CPU (as opposed to GPU textures).
3D-Graphics module (goto)
Bundles graphics primitives into higher-order objects like meshes, materials, or lights and organizes them in a scene graph for hierarchical rendering.
3D-Physics module (goto)
Implements the simulation of rigid bodies in 3D. Contains a force integrator, collision detection, and collision resolution through a constraint-based approach (Sequential Impulses).
Uses signed distance fields to generate fonts in order to render unicode text at arbitrary sizes with a minimal memory footprint. Includes a generator for SDF fonts from true type fonts and a text renderer.
Provides a framework for building simple hierarchical GUIs with some preliminary automatic layout options like widget stacking or anchoring.
TODO: add screenshots
- Catch2 for writing unit tests
- Glad for the OpenGL headers
- Vulkan SDK for the Vulkan headers
- GLFW for window creation on desktop targets
- libpng for reading PNG images
- tinygltf for reading GlTF files
- FreeType for reading TrueType font files
Except Glad and Vulkan, these dependencies are downloaded and configured automatically by the CMake build.