glBindSampler(0, 0) is needed for OpenGL backend about imgui_bundle

[pthom]

Hello.

I am quite busy these days so that I will not have time to work this in the next days. In the meantime you can compile the library by yourself and just define what is needed to get this feature.

from imgui_impl_opengl3:

// Desktop GL 3.3+ has glBindSampler()
#if !defined(IMGUI_IMPL_OPENGL_ES2) && !defined(IMGUI_IMPL_OPENGL_ES3) && defined(GL_VERSION_3_3)
#define IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
#endif

=> You need to define GL_VERSION_3_3 at compilation time.

This will not work on a mac, because of the way openGL is setup on this plaform at the present time.
See src/hello_imgui/internal/backend_impls/opengl_setup_helper/opengl_setup_glfw.cpp

    void OpenGlSetupGlfw::SelectOpenGlVersion()
    {
        #if defined(IMGUI_IMPL_OPENGL_ES3)
        {
            BACKEND_THROW("OpenGlSetupGlfw::SelectOpenGlVersion needs implementation for GLES !");
            //            SDL_GL_SetAttribute(SDL_GL_CONTEXT_EGL, 3);
            //            SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK,
            //                                SDL_GL_CONTEXT_PROFILE_ES);
            //            SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
            //            SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
        }
        #elif defined(__APPLE__)
        {
            glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
            glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
            glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);  // 3.2+ only
            glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);            // Required on Mac
        }
        #else
        {
            // GL 3.2+
            glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
            glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
            glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);  // 3.2+ only
            glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);            // 3.0+ only
        }
        #endif
    }