> "PM 2Ring" <nomail@nomail> wrote:
>> "Anthony D. Baye" <Sha### [at] spamnomorehotmailcom> wrote:
>>> I'm working on a small experiment with 3d color-space, and it seems to be
>>> working perfectly, it renders beautifully, but when it saves, the png files have
>>> a truncated color table.  It's quite distressing.
>>>
>>> I've had no obvious trouble with other renders.
>>>
>>> Also, my jpeg output seems to be broken, and the render results are completely
>>> different in windows 7.
>> POV can read jpeg for image maps, but it doesn't use jpeg as an output format,
>> due to the lossy compression.
>>
>>> I ran the same scene under both Windows and Linux using the same settings each
>>> time +a0.3 +FN24 +W800 +H600
>>>
>> The +FN24 should be +FN8 or just +FN for a 24 bit PNG; the number refers to the
>> bits per colour.
>>
>> See http://www.povray.org/documentation/view/3.6.1/219/
>>
>>> #declare r = function(x,y,z,rho) { rho*cos(atan(y/x))*sin(acos(z/sqrt(x*x +
>>> y*y))) }
>>> #declare g = function(x,y,z,rho) { rho*sin(atan(y/x))*sin(acos(z/sqrt(x*x +
>>> y*y))) }
>>> #declare b = function(x,y,z,rho) { rho*cos(acos(z/sqrt(x*x + y*y))) }
>> I'm curious as to why you're using trig functions here. An algebraic approach
>> using basic trig identities will speed things up enormously. See the Mandelbulb
>> C code I posted recently in the "Accidental Isosurface" thread, which shows how
>> to do the same functions as you require, but with no trig functions.
> 
> I could possibly simplify my approach, but it was a quick and dirty experiment;
> besides, speed isn't the issue.  The issue is color loss under Fedora, which
> could, possibly, be explained by having the wrong image libraries: except that
> it happens with all formats.
> The other issue is a discrepancy between what is rendered in windows, (3.7.0
> beta 34) and what is rendered on other systems using the same release.
> 
> For the record, the image in p.b.i was rendered in Ubuntu 9.10 using +fn32.
> Whether it's a valid usage of the argument or not, the number had no effect.
> 
> A.D.B.
> 
> 

+fnx set the per chanel depth.
+fn is 8 bit per chanel, 24 per pixel, 32 if using the alpha chanel.
+fn16 set 16 bit per chanel, 48 per pixel, 64 if using the alpha chanel.
+fn24 or +fn32 is not supported, probably defaults to +fn8.
The valid range is 5 to 16.



Alain

Post a reply to this message