Hi guys.

I have a (possibly) very silly question for you all. I've been playing around with geometry clipmaps (almost all done to Syranide's help) and I got a bit stuck. I was wondering if maybe I didn't have an up to date enough version of GLSL libs to perform the texture lookup..

So I started looking online at it appears version 3.30 which I'm using is more than adequate. However it states that ftransform() was removed back in 1.4xx. I was wondering if having some shaders using ftransform (and these shaders still work) would cause issues with other shaders.. ie hold back the level at which they work? So my worry was they were maybe preventing it from working at a level with texture lookup available.

I did say it could be a very silly question! I'm absolutely awful at understanding APIs and other peoples code generally.. so I had to ask.

I'll take any comments about being an idiot on the nose :)!

There is no such ting like GLSL lib.

If your GPU supports GL 3.3, than it surely supports vertex shader texture lookup. It is available since SM 3.0, and GL 3.3 requires SM 4.0.

You can still use ftransform(). Nobody forces you to use core profile.

Well there is a GLSL lib of some sort somewhere.. I guess it's just within the OpenGL stuff rather than a standalone thing.

But thank you.. I just wanted to check that it wasn't some well known fact that you can't use old standards with new or whatever. I guess I'll go look at what's being sent to the shaders and what they're trying to do with it.

Thanks.

Considering OpenGL, everything is implemented in drivers. That can be very good thing, because you don't need to wait for some SDK to be able to use the latest functionality. Everything is available right out of the box. But, on the other hand, if your hardware or drivers do not support some feature, you cannot emulate it through the software (like in D3D).

The version and the profile you want to be compliant to are defined by GL context you have created and #version directive in shaders. So far, OpenGL is backward compatible, and you can use whatever version you want up to the latest supported by your graphics card's drivers. Furthermore, NVIDIA allows using everything in the shades no matter what you have defined in #version directive.

You've made me realise I've forgotten pretty much everything about setting up GLSL and such now.. it's been such a long time since I've made any changes to that part of my work I had to look up information on the context and such! Appears I'm just not sending/using information correctly at the moment. Thanks for the help.