[PD] GEM: multitexturing in GEM

chris clepper cgclepper at gmail.com
Thu Jul 12 19:56:49 CEST 2007

I have multitexturing working with GLSL.  While I upload the changes
to CVS I can explain how it works.

GLSL shaders cannot directly talk to hardware like ARB ones can.  The
application side code has to tell the shader which hardware texture
unit to use.  Obviously when I compile GEM there is no way in hell to
know what the shader variables are going to be named, so another
method to tell the shader which unit to use needs to be in place.

One solution is to hardcode the names of the sampler variables, but
that is kind of a hack.  The one I put in place uses a message to the
glsl_program object with the name of the sampler and the texture unit
to use.

How to use:

1) create gemwin and turn on rendering
2) load shader
3) send a [mySamplerName $1( message to glsl_program
4) load two movies or images
5) set one of the pix_texture units to upload to the same texture unit
you told the shader to use with a [texunit $1( message

This change should be in CVS soon.  I will post an example patch in a bit.

On 7/12/07, cyrille henry <cyrille.henry at la-kitchen.fr> wrote:
> >
> > I have figured out what the GLSL multitexture problem is and have it
> > working here.  If I have a few hours today I can work on making it
> > usable, but it will probably be next week before it is done.
> >
> wow, nice
> thanks a lot.

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