In article <Xns948DB6C063518seed7@news.povray.org>,
 ingo <ing### [at] tagpovrayorg> wrote:

> > A photon map is a 3d data structure,
> 
> Not related to the thread, but would this mean that the datastructure 
> could be converted in a density_file (df3)?

Not as a DF3 file. DF3's store uncompressed, filled voxel data. An 8x8x8 
DF3 contains 512 voxels, each at a specific point in an 8x8x8 3D 
lattice. Technically you could create a voxel field from the photon 
data, but you wouldn't be able to store it...it'd be too big at any 
reasonable resolution, or blurred out at too low a resolution to be of 
any use. A 256x256x256 resolution voxel field would consume 16MB at one 
byte per voxel. 1024x1024x1024 with 24-bit RGB? 3GB. And in a field 10 
units on a side, that's a distance of just under 0.01 between photons.

Now, I'm working on an extended density format that allows sparse data, 
storing the location and value of each point rather than a value for 
every possible point. The files would be big, and there would be loss in 
location precision due to the use of integer coordinates, but it would 
be far more practical. Unfortunately, there currently are no programs 
capable of reading or writing this format, and the format itself isn't 
fully defined...I'll be starting a thread in *.programming on the 
subject soon.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: <chr### [at] tagpovrayorg>
http://tag.povray.org/

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