[Open-graphics] paradigm shift to 'raytracing'

[Hugh Fisher]

Nick LaForge wrote:
> In Plan 9, I work with rectangle images that translate throughout and
> translate on-off the visable rectangle.  Also, rectangle images
> (should be able to) scale.  Idealy, too, mathematical models could be
> visualized in real time.  Abstract things as this can be done
> perfectly with our current bag of tricks, but any hack at potraying
> reality should work with light particles: id est, it should trace
> rays.  And, could a 'raytracer' tackle abstract things just as well,
> or better, too?

Implementing an OpenGL capable frame buffer / texture mapper gives
you exactly these capabilities. You have double buffering, fully
scalable rectangular images, and other 2D image capabilities such
as alpha compositing and arbitrary image warping. OpenGL is a more
powerful 2D rendering library than Xlib (Linux), GDI (Windows), or
QuickDraw (Mac).

All the next generation 2D graphics libraries are based on 3D
OpenGL capable hardware: Xrender/Xcomposite for Linux, Quartz
Imaging for Mac, Avalon or whatever it is now called for Windows.

> 
> First this project wanted just to work in two dimensions, the way
> things were first, and seem to be going.  (I use only cheap Matrox
> silicon and plan to never again employ OpenGL.)  The Intel
> architecture great inertia -- it is here to stay.  Is it beyond
> redemption? 

This issue is raised every six months or so on the list: "won't
it be easier to just implement 2D? We don't need all this 3D stuff!"
As mentioned above, modern graphics systems expect OpenGL capable
hardware. If the open-graphics card doesn't have OpenGL, it will
take *longer* to get software written for it because people won't
be able to just cut & paste.

The first open graphics card *won't* try to implement an entire 3D
pipeline, in particular there's no hardware T&L. So it is actually
much simpler and quicker to design and build than the monsters
that ATI and nVidia are selling.

> Or will two, four, eight, ..., ad infinitum cores permit
> real time 'raytracing'?  Assume no and consider that 'video card'
> developers have less constraints (also why we have a hard time using
> stuff by Nvidia and ATI).  I think 'raytracing' will be implemented by
> 'video card' developers.

With multiple cores, real time ray tracing becomes possible. But
it will still be useful IMNSHO to have a 'smart' framebuffer
that can do image resizing and compositing itself instead of
doing that on the CPU. So the open-graphics card will still be
useful.

Implemented by video card developers? I doubt it. What is more
likely is general purpose CPUs built onto the graphics card, so
you can download a raytracer at runtime.

-- 
	Hugh Fisher
	DCS, ANU