[self-interest] OpenGL

Jecel Assumpcao Jr jecel at merlintec.com
Sat Jun 14 02:27:52 UTC 2003


On Wednesday 11 June 2003 22:31, Josh Flowers wrote:
> > Imagine a red, metalic cylinder. With a white stripe near the
> > bottom. And an orange circle in the middle wrapped half way around
> > the cylinder.
>
> I can think of any number of ways to do this, but if what you're
> saying is that the white stripe is one texture, and the orange circle
> is the other, I get your point.

I don't really care if they are multiple textures or one as long as they 
look right as I zoom closer and they are "live" (I can move the circle 
a littler further up, for example). Making them separate helps meet my 
requirements, but is not the only way as Mike's example below shows.

> Well, having read your idea's about how to implement a more scaleable
> UI, I think you've got a good solution.  There are of course
> technical details that would need to get worked out, but there always
> are (for instance, it might be difficult to ensure that the different
> rendering techniques did not look too different - I've done some very
> minimal work trying to 'dissolve' from a GL rendered scene to a ray
> traced one, and the visual differences between the two were just too
> great (often times objects would have slightly different shapes, or
> placement).  But again, my work was very precursory.

Two systems that do different approximations have images that don't 
match exactly, as you said. Even getting polygons that have a common 
edge in 3D space to continue to do so when projected into 2D was a 
problem that took a very long time to solve.

On Wed, 11 Jun 2003 19:18:33 -0700, Steve Dekorte wrote:
> The characters are rendered from a texture, so you could certainly
> render them onto a surface if you wanted to. Either way, you get
> excellent performance because you keep the data close to the logic and
> let the graphics hw do the heavy lifting.

Ok. OpenGL is an immediate mode renderer, right? This wouldn't be as 
easy in a retained mode one.

On Fri, 13 Jun 2003 04:39:06 -0000, Mike Austin wrote:
> MacOS Quartz Extreme is an OpenGL desktop, and I'd say 2D textures
> are supported very well (each window is a texture).

Thanks for the tip. I took at look at this presentation:
  
<http://www.opengl.org/developers/code/features/siggraph2002_bof/sg2002bof_apple.pdf>

This thread started with the idea of a portable graphics system for 
Self. What Apple did couldn't be used directly, but I suppose it is an 
example of what can be done.

> SGI scales pretty well :)

No it doesn't. My first web site was hosted on a SGI machine with 8 
MIPS3000 33MHz processors. It cost more than all the other computers in 
the lab put together and visitors would marvel at the environment 
mapping on a VW Beatle or the cartoon-like flight simulator. I am 
absolutely sure that in 11 years you will look back on the 128 
processor Onyx with its 8 graphics pipelines in exactly the same way as 
we now think of that old "super computer".

-- Jecel



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