mjhjmtu

I am trying to develop C/C++ applications using OpenGL. Unfortunately, I have been unable to access any functionality past OpenGL 3.0. I have Mesa version 18.0.5, Linux Mint 18 64-bit, the 4.18.1 Kernel, and Intel Integrated Graphics.

Terminal output:

 ~ $ lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation Broadwell-U 
Integrated Graphics (rev 09)
 ~ $ glxinfo | grep OpenGL
OpenGL vendor string: Intel Open Source Technology Center
OpenGL renderer string: Mesa DRI Intel(R) HD Graphics 5500 (Broadwell 
GT2) 
OpenGL core profile version string: 4.5 (Core Profile) Mesa 18.0.5
OpenGL core profile shading language version string: 4.50
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile
OpenGL core profile extensions:
OpenGL version string: 3.0 Mesa 18.0.5
OpenGL shading language version string: 1.30
OpenGL context flags: (none)
OpenGL extensions:
OpenGL ES profile version string: OpenGL ES 3.1 Mesa 18.0.5
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 
3.10
OpenGL ES profile extensions:

I am certain that my hardware supports up to OpenGL 4.4, as this machine was previously a Windows 10 machine before MS pushed/forced a broken update, and I developed using OpenGL 4.4 and GLSL 440 during that time.

Additionally, I can run OpenGL 4.4 programs on Java through JOGL, which has all the required OpenGL libraries packaged together and doesn't seem to rely on the system version at all.

So basically, why does Mesa say that the core version is 4.5, but then gives the version string of 3.0? (The same version glGetString(GL_VERSION) returns.) And how can I regain access to OpenGL 4.4? (If not 4.5!)

As I understand it, the important value is the “max core profile version”, not the “OpenGL version string”. If you don’t specify a core profile when creating your context, or if you write something like

glfwOpenWindowHint(GLFW_OPENGL_PROFILE, 0);

Mesa will give you an OpenGL 3.0 context (this sort of makes sense since profiles were introduced in OpenGL 3.0, so that’s the last version where applications can be expected not to know about them). If you want a newer version of OpenGL, you need to specify the corresponding profile:

glfwOpenWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

or

glutInitContextProfile(GLUT_CORE_PROFILE);

along with the version using glutInitContext().

Note that imposing an OpenGL version in this manner creates a strong constraint; I imagine you know what you’re doing though ;-). Some developers try to target as low a version as reasonable (OpenGL 3.2 for example) and then ask for whatever extensions they need — that often works better, since popular extensions tend to be available for a while before the corresponding OpenGL version is fully supported by the drivers.

MESA_GL_VERSION_OVERRIDE is only a debugging or Mesa development tool; it forcibly overrides the reported OpenGL version, and can be set to values which Mesa doesn’t actually support!