Hi,

This is what I ment for the randomize coords:
The code...

in the result it slightly randomizes the picture that has been applied to
the object with a parallel mapping object. (I used the floortiles that are
in the texture folder)



I'm proabably completely off track with this approach. I haven't explored
volume shaders much so far. So maybe it's better to start doing that first
and then it might get clear by itself.
The thing I don't understand is what you mean with "position". What position
are you referring to?

Arjo.


  -----Original Message-----
  From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Vesa Meskanen
  Sent: maandag 12 maart 2007 17:47
  To: [email protected]
  Subject: Re: groundfog test project


  Hi,

  > I think I understand it. But if I understand it right then I don't
  > understand why you don't put the randomization before the turbity
object.

  It is just a matter of the order of the computations. When you randomize
the position, you need to compute the new map coords value from the new
position. It was earlier done by the material map object (parallel, sphere
or whatever map - the material should actually be independent of that). When
the position changes, how can you re-evaluate Map coords again ? How does
the VSL code know what kind of parent mapping was applied (what type, what
size etc?). The answer is: using the Map vsl object, which re-evaluates the
parent mapping.


  >        Ray tracer: render engine computes position
  >            Material mapping: Parallel map computes Map coords from
position
  >                Material:
  >                        randomize map coords  **** how ?????
  >                        Position changes by randomization
  >                        Turbidity is computed from randomized Map coords

  I highlighted the important row above. How can you randomize the map
coords channel so that it's randomization matches the randomization oif the
position.  Maybe you Map coords randomization goes to negative x axis
direction, but position goes to +x axis direction! I repeat: Map coords
depends on the size, orientation and type of the parent mapping, and VSL
code normally does not know these.

  Map object takes care of such details:)


  Best regards,
  Vesa



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