> But now I also
> have to pass these values to the fragment program. Is this correct? If
> so, how do I pass values? (I haven't found a good example of this
> yet.)

Textures. If you have a line that needs a gradient texture, create one on 
the fly, it only needs to be a 1d texture, and assign relevant texture 
coordinates to the vertices of the line. If you have several lines that 
need different gradients, you can be more efficient by creating a 2D 
texture with each row representing one gradient. You do have to be careful 
with texture sampling by using nearest neighbour* rather than anything 
fancy, and you have to make sure your texture coordinates are in the 
middle of a texel (OpenGL samples texels in the centre IIRC, the docs will 
tell you otherwise).

> 3) I've already invested the time all the time in the CPU land color
> code. It currently works minus this vertex program color problem, so I
> don't know if can justify the time doing a rewrite. So is there a way
> I can continue using the vertex program, but get it to cooperate with
> my traditional color approach?

Generally, once you've abandoned the fixed-function pipeline, there's no 
mixing and matching; it's all or nothing. But I assure you, once you get 
past the pain, programmable shaders are just _soooo_ sexy!** Obviously 
real-world time-contraints can often stymie a programmer's desire to do 
the The Best Thing, and force you to stick with the 
simplest/cheapest/quickest option.

John Donovan
Sony Computer Entertainment Europe
http://www.scee.com

* My memory's hazy (and the docs are too far away), can you specify 
nearest neighbour for one axis, and linear for another?
** That's sexy in a geeky way; I have a girlfriend and most of my friends 
are flesh-and-blood, not virtual.

**********************************************************************
This email and any files transmitted with it are confidential and
intended solely for the use of the individual or entity to whom they
are addressed. If you have received this email in error please notify
[EMAIL PROTECTED]

This footnote also confirms that this email message has been checked
for all known viruses.

**********************************************************************
Sony Computer Entertainment Europe

_______________________________________________
osg-users mailing list
[email protected]
http://openscenegraph.net/mailman/listinfo/osg-users
http://www.openscenegraph.org/

Reply via email to