•On Mon, 19 Aug 2013 21:00:29 +0200, Bald Eagle  

<cre### [at] netscapenet> wrote:

> Speaking of macros, and this whole camera business...
>
> In order to clear this up for myself, and perhaps once and for all  

> (maybe)
> putting this baby to bed, I'm working on a pov file and studying  

> screen.inc to
> perhaps get a good, thorough nooby tool developed to SHOW what is goin
g  

> on.
>
> This of course leads me to a few problems, and questions that may be
> overcomplicating things and in the final result, superfluous.
>
> First, screen.inc would not work until I added an extra parameter (1) 
to  

> the
> Set_Camera input from screen.pov, since it needs 4 parameters, and it 
 

> was only
> supplying 3 - the "ortho" parameter wasn't being passed to the macro.
>
> Second, apparently there is meant to be text diplayed on the "screen" 
-
> #declare MyTextObject =
> text {
>    ttf "crystal.ttf", "target: enemy base", 0.01, <0,0>
>    scale 0.08
>    pigment {color <1.0,0.5,0.2>}
>    finish {ambient 1 diffuse 0}
> }
>
> That doesn't show up, and I'm currently investigating why.
>
> Third, my current goal is to write up something that graphically  

> demonstrates
> what's going on internally with the render engine so that the User can
  

> follow
> along with data output to the "screen" showing the values of the relev
ant
> variables.  Sort of like a dashboard on a car.  Fire up an animation.i
ni  

> file
> that moves the camera around, changes key variables that affect the  

> camera and
> view, and those variables and the result are dynamically displayed on 
the
> "screen" as the animation progresses.  Display the active directives  

> being used
> to alter the screen position or other things happening in the render(s
).
>
> Fourth, incorporate some standard scene reference objects - x,y,z axes
,
> directions of rotation, "pointers" and guides from light sources to sh
ow  

> things
> like point-at, spotlight fades, etc.
>
> Incorporates some switches to turn those guides on and off so that the
  

> user can
> either see them or not.  Turn on for scene development, turn off for  

> final
> render, or after they grasp what is going on.
>
> (I've thought about having a "dual render" - where the scene is render
ed  

> without
> any interfering stuff, and then a second render is automatically calle
d  

> from
> within the SDL at the end of the first render - is this possible?)
>
> In addition to rendering with guides from the viewpoint of the camera,
 I  

> thought
> it would be instructive and helpful to do a "meta-render" where the  

> camera and
> scene are actually shown from some other view.  A side or diagonal vie
w  

> with a
> camera point, with 4 rays extending outwards to the corners of the  

> visible
> scene, etc.
>
> While it may be a lot of work, I think it will pay big dividends in th
e  

> end,
> since the newsgroups will be freed from these repetitive questions abo
ut  

> basic
> fundamentals of how POV-Ray operates, provide a large number of workin
g  

> examples
> in the pov code, will make POV-Ray more accessible to people trying to
  

> get
> started using it, and the final animation would itself make a great  

> advertising
> tool to showcase what POV-Ray is capable of doing - because it does wh
at  

> other
> things CAN'T.
>
> If this project interests you, I'd appreciate any advice and suggestio
ns  

> as to
> what it should include, how it should be implemented, snippets of  

> helpful or
> illustrative code or full working examples - perhaps as individual pov
  

> or inc
> files to be added in, ... basically anything at all that might assist 
me  

> in
> making efficient progress and producing a worthwhile result.
>
> Anyone want to help me beat a few dead horses?
> It's National Sado-Necro-Equine Month.
>

I'm going to give screen.inc a look. Maybe it can solve my problem, thou
gh  

I doubt it. I need to have an object defined according to the camera  

position and orientation for use with a macro.

So basically what I would like to see is the following:
A) Rotation angle of the camera that can be used as a rotation value for
  

an object taking into account the up vector as well. For instance if you
  

wanted to model a specific real-life camera and test it.
B) A look_at(Pos, LookAt, Up) transform macro for objects that rotates a
n  

object exactly like a camera.


-- 

-Nekar Xenos-

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