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Sundy
05-07-2002, 01:14 AM
Hi,

Is there any way to use Secondary color Alpha in Geforce/Geforce2?

I see that there is an Extension for this but My driver is not exposing this extension. I am using the register combiners and I badly want support for secondary color alpha through vertex arrays, Can someone tell me if this is possible?

glSecondaryColorPointerEXT(4,GL_FLOAT,0,ptr);

This would help me render upto two lights in one pass using just a Geforce256/Geforce2, I saw the extension specifications in the NVIDIA page but it doesnt look complete. Could anybody let me know if I can use this in arrays without any extension being enabled?

Why have a secondary color Alpha in register combiners if you cant use it anywhere? Doesnt really make sense to me. Somebody from NVIDIA please reply!. I guess the developers in NVIDIA simply assume that the whole world has Geforce3+ Hardware and only work on that when a lot of their extensions can also work on Geforce range of cards.

And.... why is the Geforce256/Geforce2 completely forgotten by guys at NVIDIA? Simple extensions like the GL_NV_secondary_color_alpha would be beneficial even on a Geforce256!! What about all those guys who spend 250-300$ on their GeForce256/2 etc?

Thanks,
Sundar

davepermen
05-07-2002, 01:24 AM
they are not simply forgotten, but if there is no hardware interpolator for the alphavalue implemented, how could they wrap an extension around then?
the alpha is just not in the hardware as they first though its not needed.. (for specular we don't need an alphavalue http://www.opengl.org/discussion_boards/ubb/wink.gif)

result: primarycolor with rgba, secondarycolor with rgb.

they can't change that anymore..

as geforce3/4 got more programable all objects got more general, so they simply implemented the alpha, cause for some pixelshader-effects, possibly someone would like to use it (like you http://www.opengl.org/discussion_boards/ubb/wink.gif)..

so there it is in, but on the old hardware, no..

at least, so far it looks like this.. and i don't think they would not implement it if it would be in the hardware..

Sundy
05-07-2002, 01:38 AM
Cass/Matt??

Are u sure abt this?? Well, I would like to know if there was no interpolator for Sec Color Alpha? If it is there in the Hardware, I guess its good if it was exposed as it would enable upto two lights with bump+vertex attenuation to be rendered in just one pass even on a Geforce256!

Thanks,
Sundar

davepermen
05-07-2002, 04:40 AM
well.. do you think they would have implemented it for geforce3+ only then? really?

mcraighead
05-07-2002, 12:31 PM
This extension is not yet implemented.

- Matt