I have to find out how POV Ray calculate a ray. E.G. If i have a box or an
other object and i give them a light source: How can i find out what parts
of the C-Files are in use to calculate this process ? How reflect the
program this ray ? If u have any ideas how to start this difficult task
please write back..... Thanxs so far.

Mathias

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Mathias wrote:

> I have to find out how POV Ray calculate a ray. E.G. If i have a box or an
> other object and i give them a light source: How can i find out what parts
> of the C-Files are in use to calculate this process ? How reflect the
> program this ray ? If u have any ideas how to start this difficult task
> please write back..... Thanxs so far.

I think you would be better off to try and find a general explanation of the
process rather than sifting through the source.

--
David Fontaine   <dav### [at] faricynet>   ICQ 55354965
Please visit my website:  http://davidf.faricy.net/

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Mathias wrote:
> 
> I have to find out how POV Ray calculate a ray. E.G. If i have a box or an
> other object and i give them a light source: How can i find out what parts
> of the C-Files are in use to calculate this process ? How reflect the
> program this ray ? If u have any ideas how to start this difficult task
> please write back..... Thanxs so far.

	I think ... 

	Take a point on the film, shoot it through the pinhole, see what it
hits, calculate what is where it hits and what effects what it hits then
what it passes through on the way back if applicable. 

-- 
As Norman Finkelstein's mother asks, "If all of these
people are survivors, who did they kill?"
	-- The Iron Webmaster, 56

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It's always struck me as strange that this is the way that raytracing has to
work, ie start from the film or screen and work backwards. What's missing below
is that the ray has to continue until it hits a light source or goes off into
infinity (in which case it won't appear).

Matt Giwer (almost) wrote:

>         I think ...
>
>         Take a point on the film, shoot it through the pinhole, see what it
> hits, calculate what is where it hits and what affects what it hits then
> what it passes through on the way back if applicable.
>

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In article <3A0C4128.CD531D3E@hotmail.removethisbit.com>, Richard 
Morton <ric### [at] hotmailremovethisbitcom> wrote:

> It's always struck me as strange that this is the way that raytracing 
> has to work, ie start from the film or screen and work backwards. 
> What's missing below is that the ray has to continue until it hits a 
> light source or goes off into infinity (in which case it won't 
> appear).

Not quite...once it hits an object, a second ray is fired *toward the 
light source(s)* to determine whether the point is in shadow. If light 
can reach the object, the normal, distance, etc. are used to calculate 
the shading of the surface.
Firing a bunch of rays into the scene hoping to hit a point-sized light 
source would be...slow. ;-)
And it wouldn't be giving you the results you wanted anyway, it would 
only calculate specular reflection.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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Richard Morton wrote:
> 
> It's always struck me as strange that this is the way that raytracing has to
> work, ie start from the film or screen and work backwards. What's missing below
> is that the ray has to continue until it hits a light source or goes off into
> infinity (in which case it won't appear). 

	It does not have to work that way. Certainly one could compute all the
rays that will never hit the film. That shouldn't take more than a few
thousand times longer to get the same result. 

> Matt Giwer (almost) wrote:
> 
> >         I think ...
> >
> >         Take a point on the film, shoot it through the pinhole, see what it
> > hits, calculate what is where it hits and what affects what it hits then
> > what it passes through on the way back if applicable.
> >

-- 
He raped Thrace thrice.
	-- The Iron Webmaster, 288

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