Can't Start OpenGL Window - c++

Question

I've got all the libraries properly installed as far as I can tell, but for some reason, glfwWindowCreate winds up returning NULL. I'm on a Dell XPS 15 at the moment, so I'm wondering if this has to do with the fact that I'm probably running this on the integrated graphics since it's not demanding enough for it to spin up the 1050ti. I'm brand new to OpenGL in general so I'm not certain that my code is properly written, so I'll post it here as well:
glewExperimental = true;
if (!glewInit())
{
fprintf(stderr, "Failed to initialize GLEW!\n");
return -1;
}
glfwWindowHint(GLFW_SAMPLES, 4);
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 6);
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
GLFWwindow* window;
window = glfwCreateWindow(1920, 1080, "Test Window", NULL, NULL);
if (window == NULL)
{
fprintf(stderr, "Failed to initialize the window.");
std::cin.ignore();
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
glewExperimental = true;
if (glewInit() != GLEW_OK)
{
fprintf(stderr, "Failed to initialize GLEW!");
return -1;
}
std::cin.ignore();
std::cin.ignore();
I've just updated my NVIDIA drivers to the latest update, so it's (probably) not that I hope. Unfortunately, I just can't seem to get it to open a window.

Answer 1

You missed to initialize the GLFW libraray. GLFW has to be initialized by glfwInit, before it is used.
The GLEW libraray has to be initialized after a valid OpenGL context has been created and become current. See Initializing GLEW.
Change your code somehow like this, to solve your issue:
if ( glfwInit() != GLFW_TRUE ) // intialize GLFW
{
// error handling
}
glfwWindowHint(GLFW_SAMPLES, 4);
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 6);
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
GLFWwindow* window;
window = glfwCreateWindow(1920, 1080, "Test Window", NULL, NULL);
if (window == NULL)
{
// error handling
}
glfwMakeContextCurrent(window);
// now the OpenGL context is valid and current
glewExperimental = true;
if (glewInit() != GLEW_OK) // initialize GLEW
{
// error handling
}

Answer 2

If on Windows, Optimus-enabled driver would look for an exported variable. That is application have to export it to be accessible to other modules. E.g:
extern "C" {
_declspec(dllexport) DWORD NvOptimusEnablement = 0x00000001;
}
Value 1 would mean usage of high performance graphics. 0 or lack of any export would mean use of low profile.
Now, if You're on MacOs or Linux or problem might be somewhere else.. MAc doesn't like Core profiles... On linux you might forgot to disable kernel modesetting and default opensource driver.