1. OpenGL ES 2.0 (angle)
https://github.com/microsoft/angle

2. psdparse (C) Toby Thain 2004-2012
http://www.telegraphics.com.au/

3. Irrlicht Engine
http://irrlicht.sourceforge.net/

4. SDL
https://www.libsdl.org/

5. SDL_mixer
https://www.libsdl.org/projects/SDL_mixer/

6. FFmpeg
https://ffmpeg.org/

7. curl
https://curl.se/

8. OpenSSL
https://www.openssl.org/

9. FreeType
https://www.freetype.org/

10. CDX Game Development Kit
https://www.codeguru.com/cpp/g-m/directx/article.php/c4367/CDX-Game-Development-Kit.htm