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yours3lf
Adept II

Re: OpenGL Compute Shader 13.4 Driver Crash/Restart Win7 64bit

Hi there,

I've just tried this driver, the issue seems to be fixed now.
AMD Catalyst OpenGL 4.3 Graphics Driver, 7 new OpenGL Extensions - 3D Tech News and Pixel Hacking - ...

A couple of things:

-in the compute shader layout(location=...) is needed to specify an image2D binding point (glBindImageTexture), and not layout(binding=...)

-it seems like the memory barrier is not needed at all after the compute shader call (so the driver is properly figuring it out, maybe?). I suppose if I wanted to run another compute shader that writes the same memory, then I'd have to place barriers.


Thank you for fixing this!

best regards,
Yours3lf

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maizensh
Journeyman III

Re: OpenGL Compute Shader 13.4 Driver Crash/Restart Win7 64bit

That's strange, the spec explicitly says to use "binding" and not "location" in 4.4.6.2 (which points to 4.4.5).

Also, GL_ARB_shader_image_load_store specification tells:

    - Data written to image variables in one rendering pass and read by the

      shader in a later pass need not use coherent variables or

      memoryBarrier().  Calling MemoryBarrier() with the

      SHADER_IMAGE_ACCESS_BARRIER_BIT set in <barriers> between passes is

      necessary.


As I understand it, if you continue using UAVs then you must call MemoryBarrier, if you're accessing the data in a different manner then you don't need to sync.

Please correct me if I'm wrong.

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yours3lf
Adept II

Re: OpenGL Compute Shader 13.4 Driver Crash/Restart Win7 64bit

Well I used imagestore in the compute pass, but a simple texture() in the displaying pass, so I guess no barriers are required, but I'll try if it crashes with imageload.
As for the binding vs location, the driver seems really beta/alpha version so anything is possible. Hopefully the new khronos conformance tests will eliminate these, but that will be only gl4.4+

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maizensh
Journeyman III

Re: OpenGL Compute Shader 13.4 Driver Crash/Restart Win7 64bit

I tried it out on NVIDIA hardware (imagestore and a texture sample afterwards) and it worked without the barrier. But be warned, it's different hardware and in my pipeline there are multiple stages, so it takes a little time between the compute stage and the draw stage. By "little" I mean something like 2-3ms.

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