In article <483a5e6b@news.povray.org>, sco### [at] scottcom says...
> > Actually, that *won't* work as I intended. In most cases you are going
> > to be dealing with something that only have *one* side to it, like a
> > HUD.
> 
> How is a HUD with one side different to any other mesh in the algorithm
 
> Darren described?  It should just work.
> 
Umm. Comparison and contrast. First you mention the case where you think 
it "will" work, then you mention the one where your not so certain.

> > In other cases, you may be dealing with something that has a
> > complex surface, but you don't want/need to know which "triangle" was
> > touched, you need to know where on the "texture" was touched,
> 
> For example, DirectX provides a function called D3DXIntersect which takes
 a 
> mesh and a ray, then returns which face was hit and the barycentric hit
 
> coordinates within that face.  You can then do *very* simple math with th
e 
> texture coordinates of that face to work out exactly which texture 
> coordinates the pointer is over.
> 
This is a Windows, Mac *and* Linux client. OpenGL may have something 
similar, but knowing what it is doesn't necessarily help if you don't 
know how to get from that to the final result. lol I am sure its simple 
math, but..

> > which
> > "may" overlap several such triangles, if its a complex shape. Using
> > tests against which face was touched just dumps you right back in the
> > same "Oh, prim xyz was touched, now what?", case you had before, since
> > you then would have to figure out if the texture is "on" that triangle,
> > which "part" of it is on that triangle, and "if" that somehow connected
> > to what you are looking for in the script. I.e., a total mess.
> 
> No, that seems like the logical way to do it to me.  First convert the 
> pointer screen position to a ray (ie start point and direction) in 3D.  T
hen 
> make a list of possible objects the ray intersects (using simple bounding
 
> spheres or boxes), then test each of those objects with a function like
 
> D3DXIntersect, then compute the texture coordinates of the hit.
> 
> Note however that your system *might* allow the same part of texture to b
e 
> used on more than 1 part of the mesh, the GPU and APIs certainly allow th
is.
> 
Yeah, and if you place them wrong, you could have it tiled. This isn't a 
huge issue, since, frankly, the point is to make a non-tiled texture, 
used so that it works from "one" view, with no copies into other areas 
of the object. You could also "test", to make sure its the right face, 
but that adds more script overhead, which we are trying to minimize, not 
increase. The *major* things fracking SL right now are a) custom 
textures, since you can't cache them, being as most are copyrighted, b) 
idiots running bots made to "look" like real AVs, complete with clothes, 
so they can amp up their traffic scores, c) animation overrides, because 
there is currently no way to tell SL to simply, "Use Walk-Like-An-
Egyption instead of default-walk, when you are walking", for example, d)
particle effects, which some morons insist on glueing all over 
themselves, and e) scripts, both badly written ones, and ones that work 
well, but are contained in like 50 different objects in a 20 meter 
range. While some of that you can't do much about, getting rid of about 
50% of those scripts, which are all interconnected for door locks, 
stargate DHDs, linked this, linked that, etc., and reducing the textures 
"needed" to make some of those things, is bound to have some impact on 
the matter.

Someone else has already suggested adding procedural textures as well, 
as a means to bypass the issue of custom ones, in cases where its just 
damn stupid to use them, like making rocks, or any other surface that 
doesn't "need" hand drawn Photoshop images.

-- 
void main () {

    if version = "Vista" {
      call slow_by_half();
      call DRM_everything();
    }
    call functional_code();
  }
  else
    call crash_windows();
}

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