[Fenfire-dev] New interpolation system

[Benja Fallenstein]

Hi,

I've committed an improved interpolation system (implemented only in 
AWT, GL works as before) to the darcs repository.

(If you don't know, I'm trying out darcs <http://darcs.net/> as a 
revision control system for the Fenfire codebase at the moment. So far 
it seems that darcs is MUCH MUCH better than CVS or Arch -- the darcs 
interface is very easy to get into and get productive with, and no nasty 
surprises so far.)

Basically, the idea of what's different is that coordinate systems that 
have not been added into the matcher are shown during interpolation, 
non-interpolated; only keyed coordinate systems are omitted during 
interpolation.

This means that for example you can place some text on the screen 
without giving it keys et cetera, and while the text won't be 
interpolated, if it is both in the source and target vob scene, it will 
look as if it is 'interpolated' if it doesn't change position. (If it 
does change position, it will jump.)

Now that's the idea. The devil is in the details:

- If the *parent* is keyed and interpolated, you want the child to move 
with the parent. (I mean the coorder parent(s) here, not the matching 
parent!) For example, if your non-keyed text is in a node and the node 
moves, the text needs to move with it.
- If the parent is keyed and *not* interpolated, the child shouldn't be 
shown during interpolation.
- We want to use this for the boxes around things, so that we can just 
add a box around something, and if the whole thing including the box is 
interpolated, then the box itself is interpolated. However, if we have 
this lob structure:

    KeyLob
      |
    Frame
      |
   content

then we have a cs structure (in the coorder) something like this:

          box        <-- this cs has the key
        /  |  \
      /    |    \
    /      |      \
 trans   trans   trans
   |       |       |
  (bg) (content) (border)

The translations are necessary because we need to arrange the 
background, content, and border depth-wise.

However, the bg and border need to inherit the w and h of the box. We 
could place a box cs inside the trans cs, but then the w and h doesn't 
get interpolated! We need the w and h to be interpolated with the cs 
that has the key...


So it's kinda icky, but at least it works and makes working with lobs 
easier in many common cases.

- Benja