runtime error in example if IMGUI_IMPL_OPENGL_LOADER_GLAD is defined

[doug-moen]

Version/Branch of Dear ImGui:

Version 1.65 :

Back-end file/Renderer/OS: (or specify if you are using a custom engine back-end)

Back-ends: imgui_impl_opengl3.cpp, imgui_impl_glfw.cpp
OS: Ubuntu 16.04
Compiler: gcc 5.4.0

My Issue/Question: (please provide context)

examples/example_glfw_opengl3/main.cpp fails to run
if IMGUI_IMPL_OPENGL_LOADER_GLAD is defined.
The problem is here:

#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD)
    bool err = gladLoadGL() != 0;
#endif
    if (err)
    {
        fprintf(stderr, "Failed to initialize OpenGL loader!\n");
        return 1;
    }

gladLoadGL() returns 0 on error, and non-zero on success.
So the error condition is inverted.
The fix is:

    bool err = gladLoadGL() == 0;

[ocornut]

This was already fixed in master. Duplicate of #2157