glCreateShader Fails over remote connection

Question

I'm trying to run an OpenGl program on an Amazon EC2 instance. When run on local computers it works fine, but when run through the remote desktop the program crashes and I've narrowed it down to the glCreateShader(GL_VERTEX_SHADER) call.

I researched this previously when running over remote desktop on a computer in the local network and the solution I found was to use a batch script that disconnected the session and started the OpenGL exe. Then when you logged back on it was fine. tscon 1 /dest:console

Unfortunately now this seems not to work when trying to run on the Amazon instance. Does anyone have any experience with OpenGL issues over remote connections?

Answer 1

glCreateShader is one of the functions which location must be obtained at runtime using a …gl…GetProcAddress call. This call will give a valid pointer only if the function is actually supported by the installed OpenGL driver. Also even if the function is supported by the driver, the actual feature accessed by the function may not be supported by the device/OpenGL context you're using.

It's mandatory you're checking the validity of the function address assert(glCreateShader); and that the function is actually supported (OpenGL version >= OpenGL-2.0 or GL_ARB_vertex_shader and GL_ARB_fragment_shader in the list of extensions).

I'm trying to run an OpenGl program on an Amazon EC2 instance.

Virtual machines normally don't have a GPU available. The functionality you're requesting is not available without a GPU in a standard Windows installation. As a workaround, however with largely reduced performance, you can build and install the Mesa3D opengl32.dll software rasterizer alongside your program's .exe (do not install in the system path!).