[Radiance-general] real time

[Peter Apian-Bennewitz]

etsaweb wrote:

> There are several utilities in radiance to achieve interativity with 
> radiance(rview, rholo...) but all of them are based in sofware, so 
> they are a bit slow, is there any way in which radiance can make use 
> of hardware acceleration? or could be it possible in future? can 
> opengl help to it?...

Hi,
Today's hardware acceleration is polygon based. Every geometry is 
tesselated into triangles and feed more or less optimized into a 
"geometry pipeline" that is made up of specialied hardware transforming 
the 3d triangles to 2d screen triangles, removing hidden surfaces and 
painting the triangles (shading and texturing). The interface specs of 
the entry point into the pipeline are defined by OpenGL. Only very 
rudimentary lighting (termed shadow free "local" lighting with a simple 
surface model) is done at the hardware level. It could be useful in the 
Radiance context for either speeding up basic drawing functions or as a 
pure (non-physical lit) geometry display engine.
Open-GL is used by rholo to speed up "painting" of triangles and by 
"rshow" for displaying the geometry. I found the latter one useful for 
interactive display (thats why I wrote it) , but I'm still not donating 
enough time to port it to the new internal libs of R3.5, so a fresh 
version is not yet ready.
There are some ideas around as to map pre-calculated lighting "levels" 
onto polygons and then feed them though the pipeline at interactive 
rates, and there are questions as to whether stick to the geometry 
(rshow like) or a "scene cube" (rholo like) or an intelligent (read 
"fast") mix of the two. Greg had some pretty good ideas about this in 
mind years ago, which never really materialized in projects so far. (as 
far as I'm aware).

-Peter

>  
>  
> Ignacio Mun�rriz,
> Escuela de Arquitectura, Universidad de Navarra
>  
> Pta:Now i have a "rendering with radiance" ebook version and i am 
> happy!!!! , thanks Greg



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