Ron Parker wrote:
> 
> On Fri, 20 Nov 1998 13:09:34 -0500, Lewis Sellers <lse### [at] usitnet> wrote:
> >1) ability to determine the bounds of any complex object (esp. text
> >objects) which would be useful for collision detection.
> 
> What do you mean by bounds?  Do you want to find the surface of the object,
> or the bounding box?  My contributions to the superpatch allow you to
> trace arbitrary rays (thus allowing you to at least sample the surface of
> the object) and to compute the bounding box.

Big box around the object would do. :) Although for more complicated
objects (blobs etc) I assume you'd need to do some raytracing. The
superpatch is... the one at twysted.net I assume? Not tried that yet,
though I've heard of it.

> >2)ability to read heightfields data like a 2d array (so random tree and
> >rock objects, for example, sit ON the ground and not 10 ft under. :)
> 
> Since you can sample the surface of an object, you can easily determine
> the elevation of a heightfield at any given point, as well as the slope.

You can? (Min scratches his head.) Oh, you mean the superpatch can?
Hmm...
 
> >3)and the addition of translate_path, rotate_path and scale_path, which
> >are curve-based animation functions (operating similiar to say
> >color_map) using the 0 to 1 of the clock variable. Operating on all
> >objects including camera.
> 
> Please explain this in more detail.  Specifically, what syntax should this
> have?  Also, I'm having trouble determining how scale can be correlated
> with a path.  If all you're looking for is a convenient way to generate a
> spline through a series of points or scalar values, this too is in the
> superpatch (though I didn't write that patch) or available as an include
> file from Chris Colefax's page.

Well, basically it's something I mentioned a while back. Let me see if I
can remember how it went.....

ok. Assume we have an object called my1ststarship that normally faces to
position Z and is otherwise centered. Assume also we're using an .ini
that runs 60 frames from clock 0 to 1. The .pov animation code is:

object {
	my1ststarship

	translate_path {
		[0 <0,0,0>]
		[.5 <0,0,10>]
		[1 <10,10,10>]
		cubic_spline
	}

	rotate_path {
		[0 <0,0,0>]
		[.5 <0,45,45>]
		[1 <0,90,45>]
		cubic_spline
	}
}


Should be fairly obvious to you what it'll to. The ship starts at
0,0,0.  Halfway through (.5 clock) it's at 0,0,10. By 1 it's at
10,10,10. Works the same for the rotate. It would have some of the
flavouring of lathe and map objects in that the points in between would
be interpolated, etc. As you already noticed. Of course there would need
to be additional control points specified but I didn't want to muck up
the issue. :)

My math skills are not sufficent to do make the changes myself so I
never go too far in an attempt to patch my own copy of povray.

Not sure what the point of scale_path would be except that it would be
appropriate to include it for asthetic reasons. I'm sure someone would
think of a reason. :) Since it can be applied to the camera some other
attribs of the camera relating to angles, focal blur etc might also need
a _path.
 

> Granted, none of these things are yet in the official version (well, the
> include file is) but anything could happen.  The superpatch is at
> http://twysted.net/patchstation and I hope to have a new version with
> the new 3.1 windows editor, as well as a Linux and maybe a DOS port,
> online very soon.
> s

Ah. That's what I thought you were talking about. Min moosy's on over
and order's a drink.... 

-- 
Lewis A. Sellers: writer and contract Multimedia Website Developer
mailto:lse### [at] usitnet (The Fourth Millennium Foundation)
http://www.public.usit.net/lsellers/ & http://www.intrafoundation.com
http://brain-of-pooh.tech-soft.com/users/critters/bios/sellers_lewis.html

You can bug the living bejesus out of me live on ICQ @ 491461
(If I don't get back to you within a month, I'm out of prozac in some
dark corner somewhere screaming things quite unintelligable but -- most
curiously -- thick with a sumerian accent.)

"The comedy is over" -i pagliacci

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