topic Hi Ryhor, in Graphics

OpenGL bug with ARB_get_program_binary + geometry shader + UBO

Ryhor_S_ — Tue, 15 Dec 2015 22:23:36 GMT

System Used: Lenovo V580c notebook
CPU SKU: i5-3230M
GPU SKU: HD4000
Graphics Driver Version:10.18.10.4276
Operating System:Windows 10 x64
API: OpenGL 3.3
Occurs on non-Intel GPUs?: No

Steps to Reproduce:
-------------------------------
1. Run "gs_bin_ubo/gs_binary.exe" from attached zip (or build it from source)

Expected Results:
-------------------------------

See "gs_bin_ubo/expected.png" from attached zip

Actual Results:
-------------------------------

See "gs_bin_ubo/bug.png" from attached zip

Additional Information:

Test app uses ARB_get_program_binary GL extension to cache compiled shader program. If this program contains geometry shader and uniform blocks something will go wrong.

Test app draw 2 quads: a left one with a shader program compiled from GLSL source, a right one with a shader program created from binary data obtained from first shader program. It works fine on AMD and NVIDIA: 2 identical quads are drawn. On Intel GPU only the left quad is drawn correctly.

If shader program doesn't contain geometry shader everything works fine. If instead of UBO regular uniform is used everything works fine. Looks like only a combination of ARB_get_program_binary, geometry shader and UBO produces this bug.

To build test app from source you will need GLFW library (used only for window and GL context creation).

Hi Ryhor,

Michael_C_Intel2 — Tue, 15 Dec 2015 22:51:37 GMT

Hi Ryhor,

Thanks for the detailed info, I am talking to our OpenGL team and we are beginning to investigate.

-Michael

Hi Ryhor,

Michael_C_Intel2 — Thu, 07 Jan 2016 16:15:31 GMT

Hi Ryhor,

We are in a good news, bad news spot here. HD 4000 is no longer supported by the driver team. I was hoping during the debug we would find a way to make this work, but we found that it is indeed a driver issue. We checked on newer drivers and the issue is not present, but those drivers do not have support for HD 4000. I am afraid there isn't much else I can do about getting a fix as once already exists in our supported drivers.

-Michael

Thanks for info. Good to know

Ryhor_S_ — Thu, 07 Jan 2016 18:19:50 GMT

Thanks for info. Good to know it is fixed for newer GPUs.