as a development of mode x and directdraw under windows 3.1x, direct3d is a branch of the directx multimedia family which was developed directly for windows to accelerate the slow 3d display characteristics of the operating system. direct3d cooperates with directdraw in two-dimensional display. a typical situation would be, for instance, rendering a 3d object while direct- draw is placing a two-dimensional background bitmap.

    immediate mode and retained mode

    as can be assumed from the two terms, immediate mode is a programming mode that is close to the hardware. retained mode, on the other hand, is a programming mode that is largely predefined through an api interface. what does this mean in detail? looking at the two systems hierarchically, the immediate mode is also known as the low-level mode. the programming interface level is close to the hardware level and permits the programmer direct access to special functions in the hardware component concerned. the retained mode (high-level mode) makes it possible, for example, to load a defined 3d object with textures into a windows application. here it can be manipulated and moved using simple api commands. translation takes place in real time, without the need to know the technical structure of the object. for further information see the internet site www.microsoft.com/directx.