Binary shaders support in OpenGL

[shumi12321]

Hi,
I'm using a heavy shader which takes a lot of time to compile so I'm trying to use binary shaders.

I'd like to compile a shader once and just load it onto shader pipeline next time I use it. It's a common practice in Direct3D by using CreatePixelShader or CreateVertexShader functions to load compiled binary shaders.

Only thing I googled is glShaderBinary which is part of OpenGL ES and I cannot use it because glGetIntegerv with parameter GL_NUM_SHADER_BINARY_FORMATS returns 0 (obviously because I don't have OpenGL ES extension).

Is there a way to make it work without OpenGL ES?
What's the minimal version of OpenGL standard that supports this?

Thanks

[Alfonse Reinheart]

What you want is glProgramBinary, and its associated gets.

The minimum GL version that has this as a core feature is 4.1. However, pretty much any hardware that is still supported by the IVH (outside of Intel hardware of course) exposes it via ARB_get_program_binary on any platform. So all Radeon HD-class hardware and GeForce 6xxx and above.

[menzel]

However, pretty much any hardware that is still supported by the IVH (outside of Intel hardware of course) exposes it via ARB_get_program_binary on any platform.

Except for MacOS X :-(

[Alfonse Reinheart]

Yes, but there's a lot of stuff MacOSX doesn't have from OpenGL.

[shumi12321]

Thanks,
I have a few more questions.

Link provided by Alfonse says that there are vendor-specific format which can be provided by 3rd party extensions.

Does that means there are formats which produce device-independent binary program codes?

That would mean that I can compile shaders into binary format which could be loaded from completely different hardware configuration. That is important because Direct3D generates code which is completely independent. It can even be produced on a machine without 3d-accelerated graphic card using console command fxd which is part of DirectX SDK and can be run on any computer with hardware that supports chosen shader language version.

Target machines I would use are PC computers (including Windows and Linux).

[Alfonse Reinheart]

Does that means there are formats which produce device-independent binary program codes?

The API is open to permit such formats to exist. But none do currently. Nor are they likely to in the future.

[shumi12321]

That makes me sad

Is there any enumeration in GLEW and/or MESA with program binary formats they support so I could get something besides the raw numbers?

I'd like to know what's the idea behind some of those formats so I could study more about them.

Thanks again

[ZbuffeR]

The idea behind binary formats is that they load fast on their dedicated hardware.

They are the opposite of being able to run on completely different hardware. This however is the aim of GLSL.

[Alfonse Reinheart]

The format value is nothing more than a way to tell where a binary came from and whether an implementation will accept this binary. You're not going to get anything "besides the raw numbers" because they don't mean anything. NVIDIA drivers of a particular version spit out one number, AMD drivers of a particular version spit out a different number. What matters is which numbers the implementations support.

Program binary is intended to be a way of caching compiled shaders, not shipping pre-compiled shaders with your application (though you can try to do that too, as long as you precompile them on all hardware of interest). In either case, the format field is how you detect if the implementation can load that particular version of the shader.

[shumi12321]

Thanks for the detailed info.

Sorry for being so curious, but I really wan't to go into how OpenGL shaders work.

I'm now studying of ways how to create programs and I'm looking at ARB assembly language. It seems that assembly could be compiled really fast into binary and easily converted from my Direct3D shader assembly code.
However, there is a problem with that. ARB_fragment_program instructions list does not include branching and looping operations so I cannot convert my rep, if_lt and if_gt commands.

There is also NV_gpu_program4 instruction set which supports them, but they are nvidia-specific.

Is there an AMD version of instruction set or something similar since those NV functions are not likely to be available on radeon graphic cards?

Thanks