[osg-users] Crasch in extension->createShader when using remote desktop (Windows)

[François Cami]

Hi,

On Tue, Dec 17, 2019 at 3:29 PM Anders Backman <andersb at cs.umu.se> wrote:
>
> Hi all.
> Using OSG 3.6.4, Windows 10.
>
> Not sure what the current state of the world regarding Remote Desktop and OpenGL is.
> Perhaps someone can share some light onto this.
>
> If I run an application that use shaders over remote desktop from one windows machine to another I get:
>
> c:\build\VS2017\x64\osg\bin>osgsimpleshaders.exe
> Windows Error #127: [Screen #0] ChooseMatchingPixelFormat() - wglChoosePixelFormatARB extension not found, trying GDI. Reason: The specified procedure could not be found.
>
> Rendering in software: pixelFormatIndex 3

It looks like remote desktop can only do software rendering and a
limited subset of OpenGL is supported there.

> Warning: detected OpenGL error 'invalid enumerant' at Before Renderer::compile
>
> > crash.
>
> This does not happen when using fixed functionality only, for example running osgviewer with some standard obj-model works just fine.
> However, as soon as a shader is requested, OSG crashes:
>
> _glShaderHandle = _extensions->glCreateShader( shader->getType() );
>
>   Exception thrown at 0x0000000000000000 in agxViewer.exe: 0xC0000005: Access violation executing location 0x0000000000000000.
>
>
>   0000000000000000() Unknown
> > osg160-osg.dll!osg::Shader::PerContextShader::PerContextShader(const osg::Shader * shader, unsigned int contextID) Line 533 C++
>   osg160-osg.dll!osg::Shader::ShaderObjects::createPerContextShader(const std::basic_string<char,std::char_traits<char>,std::allocator<char> > & defineStr) Line 426 C++
>   osg160-osg.dll!osg::Shader::getPCS(osg::State & state) Line 470 C++
>
> Anyone with more info on this?

I think that's described in:

https://social.technet.microsoft.com/Forums/windowsserver/en-US/c8295ef8-3711-4576-9293-2c4965280165/opengl-and-remote-desktop?forum=winserverTS

which includes a workaround which may, or may not be suitable to your use-case.

François

> Is there any way around this?
>
> --
> __________________________________________
> Anders Backman, HPC2N
> 90187 Umeå University, Sweden
> anders at cs.umu.se http://www.hpc2n.umu.se
> Cell: +46-70-392 64 67
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