I need to keep the pack/unpack alignment changeable for some old datasets (cannot meet the default alignment = 4 ).
Is there ARB compatibility mode for old features that I can use to enable these deprecated functions?
In the default mode with ATI vendor, these functions do not work anymore.
This issue is solved by setting an OpenGL version number such as 2.1.
In this case, ATI driver will use latest OpenGL version (in my case it's 4.4) with Compatibility Profile.
If I set a valid OpenGL version (3.3 to 4.4), even though I set CompatibilityProfile, the driver sticks to CoreProfile and cannot recognize all the legacy OpenGL functions.