[Open-graphics] (OT?) Real-time image processing: If games don't motivate...

[James Richard Tyrer]

Nick LaForge wrote:
> I retain my position that today's popular fancy "pixel shader" hacks
> to simulate reality (as conceived in some artist's head) case by case
> are nothing more than toys, and that any serious attempt should be
> done by tracing light rays (in software, or at least in hardware
> separate from the video adapter).

You are correct.  Shaders are implemented to do shading (Gouraud 
shading, Phong shading, and improvements on them).  And by
definition 'shading' is not designed to simulate reality, it was
originally developed for the purpose of making things appear to be three
dimensional.  It is really only useful for CAD, games, cartoons, and 
(now) fancy GUIs.

I believe that there are two methods for actually emulating reality: ray
tracing and radiosity.  Both of these are beyond the capabilities of a
Video adapter.

To do reality, a video board would need an array processor.  You want a 
video board that is a frame buffer and 3 DACs and 2 ClearSpeed 
processors.  Perhaps there are some special functions that would also 
benefit from TenSillica processors.  Note that if this is going to run 
on a PC that you probably want VGA hardware as well.

Somethings in an OpenGL based board are going to help.  For example, I 
suggested that a pixel shader should be able to do a 4 by 4 matrix 
multiply. in 4 clocks (pipelined).  If you have an array of MAC float 
units, that are individually accessible, this would also be useful.

-- 
JRT