[Radiance-general] Mesh Rendering Performance

[Lars O. Grobe]

Hi,

just tried out, replaces my meshes by obj2rad-oconv-generated 
instances. May be faster, but now my rpict-process takes 1.4 GB instead 
of 700 MB ;-) So I guess I will have to stay with those "slow" 
meshes...

CU Lars.

P.S.: Concerning optimizations: I think trying to introduce assembler 
into radiance code is a bad idea, as it breaks portability, a great 
strength of the current code. Still, I think one should think about if 
the code could not be written to be more vector-friendly. Than 
compilers could do the rest (auto-vectorization is even in gcc since 
4.0), and those who want to try (like me ;-) could simple replace some 
functions. Some ideas would be like passing not only one ray, but ray 
clusters to the subfunctions, so that these could be implemented to do 
calculations in parallel. Another help would be to replace the 
unflexible datatypes by unions. I ran into trouble when I just wanted 
to Altivec some routines. As mat4, fvec etc are simply arrays, I have 
to get the data in a altivec-suitable format, which causes overhead. If 
they had been e.g. unions (containing nothing but an array), I would 
have simply changed this to be an union of array and vector. All 
unchanged functions would work as now, and still I could directly apply 
altivec code on data. Those who think altivec is out because Apple 
build x86: this year we might see the first cell-processor machines. 
And vector units are built into almost all platforms today.
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