Force OpenGL 2.1 context

support
1

mariojmartin wrote on Wednesday, June 04, 2014:

Hi, I have the opposite problem for creating the OpenGL context.
I am developing an application that may have to work with old systems, so I am trying to create an OpenGL 2.1 context in my computer, but it always create a greater version.

I am using this lines with no luck:
glfwWindowHint(GLFW_CONTEXT_VERSION_MAYOR, 2);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);
GLFWwindow* window = glfwCreateWindow( width, height, title, NULL, NULL );

Is any way to to force an OpenGL 2.1 render context?

2

elmindreda wrote on Wednesday, June 04, 2014:

Drivers are not required to implement older versions, so if the above doesn’t work then no. What you can do is use a modern extension loader that lets you generate a loader for 2.1 only, and then explicitly set the GLSL version in each shader. That’ll get you most of the way.

3

mariojmartin wrote on Wednesday, June 04, 2014:

Thanks for the explanation.
I have tinkered a little and have found a workaround myself.

My laptop has both an INTEL Graphics and an NVIDIA graphic card. It seems that by default, applications use the INTEL’s chip. By going into the NVIDIA’s control panel and change the configuration and explicit the application to be launched using the NVIDIA’s graphic card, the drivers now allow me to create an OpenGl 2.1 context.

4

elmindreda wrote on Wednesday, June 04, 2014:

GLFW has a compile-time option for that.