Alain <ele### [at] netscapenet> wrote:
> sirhenjo nous apporta ses lumieres en ce 2007/11/16 03:11:
> > "Zeger Knaepen" <zeg### [at] povplacecom> wrote:
> >> "sirhenjo" <sir### [at] hotmailcom> wrote in message
> >> news:web.473cafc7fcd9bf9af721d5e80@news.povray.org...
> >>> Okay, thank you all. It seems that POV-Ray is indeed capable of doing it.
> >>> However, to make it really viable for me, I need some more functionality.
> >>> During
> >>> the raycasting I want to make some extra checks.
> >>>
> >>> For example, I have multiple objects in front of eachother with some space
> >>> between them. Instead of writing a depth map of the scene, letting rays
> >>> end
> >>> whenever they hit any object, I may want to write the depth values of an
> >>> complete second object.
> >>>
> >>> To achieve this I may need to let the ray keep till it hits the 3rd face,
> >>> ignoring the first 2 faces.
> >>>
> >>> Is this possible at all?
> >> uhm, just remove the blocking object?
> >>
> >> I don't get it :)
> >>
> >> cu!
> >> --
> >> #macro G(b,e)b+(e-b)*C/50#end#macro _(b,e,k,l)#local C=0;#while(C<50)
> >> sphere{G(b,e)+3*z.1pigment{rgb G(k,l)}finish{ambient 1}}#local C=C+1;
> >> #end#end _(y-x,y,x,x+y)_(y,-x-y,x+y,y)_(-x-y,-y,y,y+z)_(-y,y,y+z,x+y)
> >> _(0x+y.5+y/2x)_(0x-y.5+y/2x)            // ZK http://www.povplace.com
> >
> >
> > Heheh, should have said "without removing the blocking object".
> > It may seem like something silly to do, but I have my reasons for this question.
> >
> >
> Is it that you wand to see the object in the back trough that in the front?
>
> --
> Alain
> -------------------------------------------------
> You know you have been raytracing for too long when the animation you render
> will be finished after yourself.
> Urs Holzer

What I want to to write several depth levels to one particular texture, using
the RGBa channels for 4 different depth levels.

I want to store 4 depth levels at 0% 33% 66% and 100% to one texture. Removing
objects in the front won't help me for complex scenes.

Some basic algorithm I need during the raycasting is a counter of intersected
faces and the distance between them.
Can I add some logic/algorithm to the raycasting?

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"sirhenjo" <sir### [at] hotmailcom> wrote in message 
news:web.47440808fcd9bf9a1d0a17590@news.povray.org...
> Alain <ele### [at] netscapenet> wrote:
>> sirhenjo nous apporta ses lumieres en ce 2007/11/16 03:11:
>> > "Zeger Knaepen" <zeg### [at] povplacecom> wrote:
>> >> "sirhenjo" <sir### [at] hotmailcom> wrote in message
>> >> news:web.473cafc7fcd9bf9af721d5e80@news.povray.org...
>> >>> Okay, thank you all. It seems that POV-Ray is indeed capable of doing 
>> >>> it.
>> >>> However, to make it really viable for me, I need some more 
>> >>> functionality.
>> >>> During
>> >>> the raycasting I want to make some extra checks.
>> >>>
>> >>> For example, I have multiple objects in front of eachother with some 
>> >>> space
>> >>> between them. Instead of writing a depth map of the scene, letting 
>> >>> rays
>> >>> end
>> >>> whenever they hit any object, I may want to write the depth values of 
>> >>> an
>> >>> complete second object.
>> >>>
>> >>> To achieve this I may need to let the ray keep till it hits the 3rd 
>> >>> face,
>> >>> ignoring the first 2 faces.
>> >>>
>> >>> Is this possible at all?
>> >> uhm, just remove the blocking object?
>> >>
>> >> I don't get it :)
>> >>
>> >> cu!
>> >> --
>> >> #macro G(b,e)b+(e-b)*C/50#end#macro _(b,e,k,l)#local C=0;#while(C<50)
>> >> sphere{G(b,e)+3*z.1pigment{rgb G(k,l)}finish{ambient 1}}#local C=C+1;
>> >> #end#end _(y-x,y,x,x+y)_(y,-x-y,x+y,y)_(-x-y,-y,y,y+z)_(-y,y,y+z,x+y)
>> >> _(0x+y.5+y/2x)_(0x-y.5+y/2x)            // ZK http://www.povplace.com
>> >
>> >
>> > Heheh, should have said "without removing the blocking object".
>> > It may seem like something silly to do, but I have my reasons for this 
>> > question.
>> >
>> >
>> Is it that you wand to see the object in the back trough that in the 
>> front?
>>
>> --
>> Alain
>> -------------------------------------------------
>> You know you have been raytracing for too long when the animation you 
>> render
>> will be finished after yourself.
>> Urs Holzer
>
> What I want to to write several depth levels to one particular texture, 
> using
> the RGBa channels for 4 different depth levels.
>
> I want to store 4 depth levels at 0% 33% 66% and 100% to one texture. 
> Removing
> objects in the front won't help me for complex scenes.
>
> Some basic algorithm I need during the raycasting is a counter of 
> intersected
> faces and the distance between them.
> Can I add some logic/algorithm to the raycasting?
>

I have to confess that I'm not completely sure what you're asking. What 
you've described conjures up the image of you wanting to do something like 
take slices through a scene, rendering the top slice (everything in the 
scene) in Red, then, on the next render, taking a slice 33% into the scene 
and rendering in Green etc.

If you do what Alain suggested in his response of 15th Nov, (create one big 
union of all of the objects in the scene), then you can take slices by 
differencing the composite object with a plane that you can move forward 
through the scene file for each frame. This would mean that the camera will 
only 'see' those parts of objects that are beyond a certain 'depth'.

Did I get anywhere close to what you want?

Regards,
Chris B.

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