cg shader references

I want to learn how to write my own shaders.
Can someone point me to a good place where I can learn?
The simpler, the better. Thanks

panda’s cg is a little bit different. It’s basically the vertex shader and pixel shader in one file with a few key words in the arguments.

For general Cg: Try the Cg Tutorial on nVidia’s website. It’s now free!
For panda’s own cg: Once you understand normal cg, try reading the manual on cg and then try to understand the samples.

Please also see this post:
discourse.panda3d.org/viewtopic.php?t=4339

I’ll check these out. Thanks