I'm running Windows 10 64-bit, latest drivers, R9 390.
If I include "#extension GL_AMD_vertex_shader_viewport_index : require" within a vertex shader I get:
ERROR: 0:5: error(#61) Required extension is not found. Extension "GL_AMD_vertex_shader_viewport_index" is not supported
ERROR: error(#273) 1 compilation errors. No code generated
This is despite the fact that querying the extension reports it as supported, either via "glewIsExtensionSupported" or "glGetString(GL_EXTENSIONS)". I've tried a combination of profile versions, GLSL versions, etc, all the same result. Note this works 100% fine on NVIDIA cards. Am I doing something wrong, or is this a driver bug?
Simple test-case attached, note the console output: http://downloads.flyinside-fsx.com/AMDExtensionBug.zip
I'll patch this through to the GL team, thanks for reporting.
The repo needs the Visual Studio debug runtime, do you happen to have one which is built in release?
Sorry about that, here is a Release build: http://downloads.flyinside-fsx.com/AMDExtensionBugRelease.zip
Thank you very much for looking into it!
One of our GL engineers is already looking into this. We're going to get back to you with more information as soon as possible.
The bug has been fixed internally, so it should no longer in the next driver release (or two).