Dreamcast SDL and OpenGL.

Simple DirectMedia Layer is a cross-platform multimedia library designed to provide low level access to audio, keyboard, mouse, joystick, 3D hardware via OpenGL, and 2D video framebuffer.

Chui’s SDL port for Dreamcast is a SDL (v1.2.9) driver and it is based on Bero’s driver, but it has new features.

http://chui.dcemu.co.uk/sdl.html