From: Rodolphe Ortalo <ortalo@laas.fr>
  To  : ggi-develop@eskimo.com
  Date: Fri, 21 Aug 1998 00:26:26 +0200 (MET DST)

Re: LibGGI3D RFC

On Thu, 20 Aug 1998, Jon M. Taylor wrote:
> 
> > Okay, drawing with textures enabled is only a particular way of shading.
> > But it also implies a different number of parms for the function that
> > draws triangles...
> 
> 	Nope.  It all goes into the particular shader_data struct, which
> gets passed to the shader function via a void pointer.  All you need is
> the one void pointer and the one shader_function_type pointer and you are
> all set. 
> 
> > So, I don't think you can simply provide ggi3dDrawTexturedTriangle(x,y,z,u,v)
> > through a display target, you also need the extension lib (because of the
> > u,v parms...)
> 
> 	No, all you need is a different shader function.

That I don't understand.

How can you draw a textured triangle if you don't pass to the drawing
function the specific texture (well, that you could store in the graphic
context, but it would be costly) and, more important, the (u,v)
coordinates of the texture inside the triangle ????

Do you mean x,y,z are in real 3D coordinates and the library itself
computes the 2D projection (hence the u,v coordinates) ?

There is something I miss here. (Well, I knew that already, can you
help me ?)

Rodolphe

PS: Sorry for bothering everyone on that... :-(