Alternate frame rendering

Alternate Frame Rendering (AFR): divide, conquer and merge

AFR is a parallel graphics rendering architecture, which combines multiple video graphic controllers (within a single PC) into a single monitor, in order to improve or accelerate the video rendering peformance. This technique is useful for rendering 3D video sequences in real time, generating and/or filtering textured polygons and performing other computationally intensive rendering tasks, typically associated with computer gaming, CAD and 3D modelling.

AFR belongs to a class of parallel rendering paradigms, which subdivide a four dimmensional image frame sequence (x,y,z and time) into smaller regions, each of which is then assigned to a different physical processor within a mutli-processor array. Note that the regional boundaries may be defined in space or in time.

If a computer was born with two video cards merged into a single video monitor, for example, then

  Alternate Frame Rendering (AFR)  ==>  One GPU computes all the ODD video frames, the other renders the EVEN frames.

  Scissors                         ==>  One GPU renders the top half of each video frame, the other does the bottom.

  Checker board                    ==>  As the name implies, the image is split into smaller squares, ....

N.B. The term GPU (above) refers to the one inch french frie soldered onto a typical video card,

    i.e. the Video Graphics Unit

An example of the (AFR, scissors & Checker Board) sytem is employed by ATI's ATI CrossFire video cards, plugged into an Asus Asus P5W HD motherboard, which is implemented as follows:

  1) Two (master/slave)video cards, each with its own Graphic Processor Unit(GPU),
     are installed into a single compatible mother board with dual graphic slots.

  2) Both video outputs are merged into a single monitor, using a linking
     video cable, through a compositing chip on the master video card.

  3) The software video driver then divides the "rendering load" equally between
     the two GPUs, using one of several "divide and conquer schemes:"

  Hardware requirements are:
    1) One CrossFire Edition video card (Master)
    2) One CrossFire Ready   video card (Slave)
    3) Compatible mother board with two graphic port slots,

--MJStadler 20:23, 16 October 2006 (UTC)