Flex Engine

Flex Engine is a personal game engine I began work on in February 2017. I use it as a playground for learning about real-time technniques. I try to keep master reasonably stable, and therefore update it infrequently. See development for the latest changes.

Notable Features

• Vulkan and OpenGL backends
• Signed-distance field font generation & rendering
• Physically based shading model
• Image based lighting
• Screen-space ambient occlusion
• Stable cascaded shadow mapping
• Conditional checksum-based shader compilation
• Scene editor with serialization
• Profiling tools
• In-game scripting language

Basic implementation of Cascaded Shadow Mapping

Profiler overlay showing a breakdown the CPU-time of a single frame

Some of the editor windows

Screen-Space Ambient Occlusion (SSAO)

GBuffer (top-left to bottom-right): position, albedo, normal, final image, depth, metallic, AO, roughness

See more screenshots here

Building Flex (Windows-only)

If you want to build Flex Engine on your own system, follow these steps. You an always download the latest release binaries here if that's what you're after.

Requirements:

• Visual Studio 2015 (or later)
• GENie

Steps

1. Recursively clone the repository to get all submodules
2. Ensure GENie is either on your PATH, or genie.exe is in the scripts/ directory
3. Run scripts/generate-vs-*-files.bat (this simply runs the command genie vs2015 or genie vs2017)
4. Open build/FlexEngine.sln
5. Build and run!

Dependencies

Flex Engine uses the following open-source libraries:

• Bullet - Collision detection & rigid body simulation
• FreeType - Font loading
• glad - OpenGL profile loading
• glfw - Window creation, input handling
• glm - Math operations
• ImGui - User interface
• OpenAL - Audio loading and playback
• stb - Image loading
• cgltf - Mesh loading

License

Flex engine is released as open source under The MIT License. See license.md for details.

Acknowledgements

A huge thank you must be given to the following individuals and organizations for their incredibly useful resources:

• Baldur Karlsson of github.com/baldurk/renderdoc
• Alexander Overvoorde of vulkan-tutorial.com
• Sascha Willems of github.com/SaschaWillems/Vulkan
• Joey de Vries of learnopengl.com
• Andrew Maximov for the pistol model and textures artisaverb.info/PBT.html
• FreePBR.com for the high-quality PBR textures
• All authors and contributors to the open-source libraries mentioned above

Blog

Stay (somewhat) up to date about this project on my blog at ajweeks.com/blog