Function extensions

source/glbinding-aux/source/ContextInfo.cpp:44–88

// parameters via pointers while maintaining a single implementation.

std::set<GLextension> extensions(std::set<std::string> * const unknown)
{
    const auto v = glbinding::aux::ContextInfo::version();

    if (v <= glbinding::Version(1, 0)) // OpenGL 1.0 doesn't support extensions
    {
        return std::set<GLextension>{};
    }

    auto extensions = std::set<GLextension>{};

    if (v < glbinding::Version(3, 0))
    {
        const auto extensionString = glGetString(GL_EXTENSIONS);

        if (!extensionString)
        {
            return extensions;
        }

        std::istringstream stream{ reinterpret_cast<const char *>(extensionString) };
        auto extensionName = std::string{ };

        while (std::getline(stream, extensionName, ' '))
        {
            insertExtension(extensionName, &extensions, unknown);
        }
    }
    else
    {
        auto numExtensions = 0;
        glGetIntegerv(GL_NUM_EXTENSIONS, &numExtensions);

        for (GLuint i = 0; i < static_cast<GLuint>(numExtensions); ++i)
        {
            const auto name = glGetStringi(GL_EXTENSIONS, i);
            if (name)
            {
                insertExtension(reinterpret_cast<const char*>(name), &extensions, unknown);
            }
        }
    }

    return extensions;
}

bool supported(const std::set<gl::GLextension> & extensions, std::set<gl::GLextension> * unsupported)
{