Direct3D

Direct3D is a proprietary Microsoft library for hardware-accelerated rendering. On Windows systems, ZDoom uses it to display 2D images (such as HUD elements, menus, and so on), as well as to display the rendered scene, but not to render the scene itself.

Features allowed by Direct3D include support for truecolor images (without forcing them into the palette) and support for choosing on which monitor to display.

In case of incompatibility between Direct3D and the graphic hardware used, the console variable vid_forceddraw can be set to true so as to use the older DirectDraw library instead.