Re: INFO.

[Lutz Sammer <johns98@gmx.net>]

Steve Baker wrote:
> 
> Lutz Sammer wrote:
> >
> > Steve Baker wrote:
> > > [CUT]
> > >
> > > * To display 2D sprites in a game, you could write your own
> > >   code to talk to libsvga or Xlib - but for a beginner, you'll
> > >   want to start with a library of convenient sprite rendering
> > >   routines.  Perhaps you should learn Clanlib or one of the
> > >   other packages that do these things well.
> >
> > A question I have to this part is: How to use a 3D engine todo
> > the 2D stuff. Scaling, rotating and transparent effects shouldn't
> > be a problem for a 3D engine.
> 
> OH!  I see!
> 
> Easy - stuff the sprite into a texture map - and draw a textured
> quadrilateral to draw the sprite.
> 
> Rotating, translating, scaling the polygon (which is EASY) causes
> the sprite to do the same thing.
> 
> Alpha-blended textures deal with the transparency.
> 
> To *animate* a sprite is a little harder.  You can either define
> one texture for each step of the animation and switch textures
> >from frame to frame - or you can pack all of the animation steps
> up into one big texture map and change the texture coordinates
> on the polygon to select which sub-image you need.
> 
> Assuming you have hardware 3D accelleration, an OpenGL (Mesa)
> 'sprite' engine can be spectacularly fast with arbitary angle
> rotation effects and scaling costing *nothing*.
> 
> You should also be able to have larger sprites than with
> a software-only sprite engine because the 3D hardware can
> push polygons MUCH faster than the main CPU - even with
> translucent blending and such like.
> 

That is exactly what I want to hear. But are there any small
tutorials? It is easier to use and modify a running program
than writing it all new. 

Bye,
Johns