[GEM-dev] more on multitexturing

[chris clepper]

On 12/19/05, james tittle <tigital at mac.com> wrote:

> ...definitely add it if it works ;-)  But I'm not really
> understanding how this would be accessed:  are you using
> pix_multitexture to assign to texture unit, then passing this state
> onto geos?  How do the geos know that there are multiple texture
> units being addressed, or where to stop?
>

glTexCoord2f() only works for the default unit 0, and the other calls
are needed to texture properly to the remainder of the units.  For
testing, I only rigged up unit 1 and used pix_multitexture to set the
texUnit for each render chain to 0 and 1 respectively.  After making
the change to SetVertex() [square] could accept the texture.  I
actually had to texture to some geometry to get the shader to work at
all - without setting up glMultiTexCoord2fARB(GL_TEXTURE1_ARB...) the
texture was one big pixel.   I don't know if alternatives exist or
not, but every reference I found had the glMultiTexCoord2fARB() calls
for each texUnit used.  I think we might have to rewrite the Geos to
accommodate the possibility of any of the texture units being enabled
upstream or add something to GemState to let them know which unit(s)
to use.