Gena wrote:
>>No, i don't agree here.  You are seriously limited in what techniques
>>you can use when implementing a plant system in SDL.  Most part of
>>developing a plant generator is not the code generating the actual mesh
>>but the underlying stuff generating the plant structure.  Making this
>>both flexible and intuitive to use at the same time is the real
>>challenge and quite impossible with the limited means of the SDL.
> 
> 
> But there are several different tree system implemented already in SDL :)
> I think that currently available SDL features would be enough. 

That's not the question, of course you can in theory implement anything 
in SDL.  But i doubt anyone will really write an universal plant system 
in SDL let alone maintain it.

The currently existing SDL based plant generators are quite simple and 
quite specialized.  For a really universal plant system you need to be 
able to not just adjust parameters of a fixed growth algorithm but must 
be able to define the growth rules themselves.  Advanced things like 
self collision detection would be extremely ugly and slow with the 
current SDL.

> 
> I meant that now you have to write patch and recompile the whole
> program rather than just write plug-in for it.

I don't understand why it is more difficult to compile a patched POV-Ray 
than compiling an imaginary 'plug-in'.

>>Well - the idea of a patch is not to have the user code in C to use it.
>>    The best approach IMO is to have a fairly low level interface to SDL
>>that allows very flexible use but have the actual plant generation
>>internally for good performance.
> 
> Could you clarify what you mean?

Sure.  There is an internal plant generator that generates a mesh 
object.  There is a SDL interface to this which can be used to define 
the plant system rules that are interpreted by the plant system.  In 
terms of language syntax it would be a new shape which behaves exactly 
like a mesh.  The rules could be given with classical L-System strings 

set of macros could be created that generates common plant shapes with a 
limited set of adjustable parameters.

Christoph

-- 
POV-Ray tutorials, include files, Landscape of the week:
http://www.imagico.de/ (Last updated 31 Oct. 2005)
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