[osg-users] [build] How to properly use the OSG_GL3_AVAILABLE CMake option?

John Price john.price00 at gmail.com
Wed Nov 25 13:02:23 PST 2009


Hi Robert and Paul,

Thank you both for your replies. Your answers affirmed my own investigations into gl3.

For Paul - my OSG project is being developed for Win32 x64. I have just moved it to Windows 7 x64. It is tied to Windows because it is designed to work in concert with other Windows commercial apps that will probably never be ported to Linux.

My project is still in development and has a long term objective. My view is forward looking, so I am interested in embracing gl3 as development progresses. I am primarily developing for nVidia hardware, and am particularly interested in nVidia extensions to gl3 that they refer to as "Bindness Graphics".

nVidia states:
	Bindless Graphics refers to changes to OpenGL that can enable close to an order of magnitude improvement in the CPU-limitedness 	of graphics applications.

	Bindless Graphics has the following desirable properties:
•	The driver need not dereference a vertex buffer or constant buffer on the CPU in order for the GPU to use it. 
•	Relieves the limits on how many buffer objects can be accessed at once by shaders 
•	Buffer objects are accessed as C-style pointer dereferences in the shading language 
•	Allows for dependent pointer fetches, enabling more complex scene graph structures to be built into buffer objects providing significant new flexibility in the use of shaders. 

Measurements have shown that bindless graphics can result in more than 7x speedup!

Unfortunately the nVidia OpenGL SDK which usually provides code examples seems to be stuck at this time at the GeForce 8 gl2.1  level. Hopefully this will be updated sometime in the future.

As it seems that I am at about the same juncture as everyone else with respect to gl3, I don't feel so alone or incompetent as I did when I first began asking questions. I plan to take Paul's advice and begin writing gl3 code. If I come up with anything useful I will gladly contribute it with a submission.

I have found that the Red Book 7th Edition covers gl3 and gl3.1. I also found the book Beginning OpenGL Game Programming 2nd Edition by Luke Benstead has been updated to gl3. I have just ordered it, but don't have it yet.


Thank you!

Cheers,
John

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