openGL Extensions availability and different GPU brands

Question

I'm using openFrameworks on Windows, which uses GLFW and GLEW, and I'm having issues regarding extensions availability on different GPUs brands.

Basically, if I run my program on openGL 2, the extensions are available. But if I change to openGL 3.2 or higher, all the extensions became unavailable on Nvida (tested on a* GTX1080) and Intel (*UHD), but not on AMD (*Vega Mobile GL/GH and RX 5700).

This translates to not being able to use GL_ARB_texture_float, and therefore my compute shaders don't work as intended.

I'm using openGL 4.3, for the compute shader support and for support of the Intel GPU. All drivers are up to date and all GPU support GL_ARB_texture_float.

Also, enabling the extension on the GLSL does nothing.

This is how openFrameworks makes the context:

glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_API);
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, settings.glVersionMajor);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, settings.glVersionMinor);
if((settings.glVersionMajor==3 && settings.glVersionMinor>=2) || settings.glVersionMajor>=4)
{
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
}
if(settings.glVersionMajor>=3)
{
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
}

Not sure what is going on, nor exactly how to search for an issue like this. Any pointers are welcome!

Answer 1

ARB_texture_float is an ancient extension that was incorporated into OpenGL proper in 3.0. That is, if you ask for 3.2, you can just use floating-point formats for textures. They're always available.

Furthermore, later GL versions add more floating-point formats.

Since there is no core profile of OpenGL less than version 3.2, I suspect that these implementations are simply not advertising extensions that have long since been part of core OpenGL if you ask for a core profile.