Method initialize

src/SFML/Window/GlContext.cpp:876–1042

///////////////////////////////////////////////////////

////////////////////////////////////////////////////////////
void GlContext::initialize(const ContextSettings& requestedSettings)
{
    // Activate the context
    setActive(true);

    // Retrieve the context version number
    int majorVersion = 0;
    int minorVersion = 0;

    // Try the new way first
    auto glGetIntegervFunc = reinterpret_cast<glGetIntegervFuncType>(getFunction("glGetIntegerv"));
    auto glGetErrorFunc    = reinterpret_cast<glGetErrorFuncType>(getFunction("glGetError"));
    auto glGetStringFunc   = reinterpret_cast<glGetStringFuncType>(getFunction("glGetString"));
    auto glEnableFunc      = reinterpret_cast<glEnableFuncType>(getFunction("glEnable"));
    auto glIsEnabledFunc   = reinterpret_cast<glIsEnabledFuncType>(getFunction("glIsEnabled"));

    if (!glGetIntegervFunc || !glGetErrorFunc || !glGetStringFunc || !glEnableFunc || !glIsEnabledFunc)
    {
        err() << "Could not load necessary function to initialize OpenGL context" << std::endl;
        return;
    }

    glGetIntegervFunc(GL_MAJOR_VERSION, &majorVersion);
    glGetIntegervFunc(GL_MINOR_VERSION, &minorVersion);

    if (glGetErrorFunc() != GL_INVALID_ENUM)
    {
        m_settings.majorVersion = static_cast<unsigned int>(majorVersion);
        m_settings.minorVersion = static_cast<unsigned int>(minorVersion);
    }
    else
    {
        // Try the old way

        // If we can't get the version number, assume 1.1
        m_settings.majorVersion = 1;
        m_settings.minorVersion = 1;

        if (const char* version = reinterpret_cast<const char*>(glGetStringFunc(GL_VERSION)))
        {
            // OpenGL ES Common Lite profile: The beginning of the returned string is "OpenGL ES-CL major.minor"
            // OpenGL ES Common profile:      The beginning of the returned string is "OpenGL ES-CM major.minor"
            // OpenGL ES Full profile:        The beginning of the returned string is "OpenGL ES major.minor"
            // Desktop OpenGL:                The beginning of the returned string is "major.minor"

            // Helper to parse OpenGL version strings
            static const auto parseVersionString =
                [](const char* versionString, const char* prefix, unsigned int& major, unsigned int& minor)
            {
                const std::size_t prefixLength = std::strlen(prefix);

                if ((std::strlen(versionString) >= (prefixLength + 3)) &&
                    (std::strncmp(versionString, prefix, prefixLength) == 0) && std::isdigit(versionString[prefixLength]) &&
                    (versionString[prefixLength + 1] == '.') && std::isdigit(versionString[prefixLength + 2]))
                {
                    major = static_cast<unsigned int>(versionString[prefixLength] - '0');
                    minor = static_cast<unsigned int>(versionString[prefixLength + 2] - '0');