Method attachGLContextToRender

Engine/GPUContextPool.cpp:100–186

}

OSGLContextPtr
GPUContextPool::attachGLContextToRender(bool checkIfGLLoaded)
{
    if (checkIfGLLoaded && (!appPTR->isOpenGLLoaded() || !appPTR->getCurrentSettings()->isOpenGLRenderingEnabled())) {
        return OSGLContextPtr();
    }
    QMutexLocker k(&_imp->contextPoolMutex);

    // Context-sharing disabled as it is not needed
    OSGLContextPtr shareContext;// _imp->glShareContext.lock();
    OSGLContextPtr newContext;
    SettingsPtr settings =  appPTR->getCurrentSettings();
    GLRendererID rendererID;
    if (settings) {
        rendererID = settings->getActiveOpenGLRendererID();
    }

    int maxContexts = settings ? std::max(settings->getMaxOpenGLContexts(), 1) : 1;

#ifndef NATRON_RENDER_SHARED_CONTEXT
    while (_imp->glContextPool.empty() && (int)_imp->attachedGLContexts.size() >= maxContexts) {
        _imp->glContextPoolEmpty.wait(k.mutex());
    }
    if ( _imp->glContextPool.empty() ) {
        assert( (int)_imp->attachedGLContexts.size() < maxContexts );
        //  Create a new one
        newContext = std::make_shared<OSGLContext>( FramebufferConfig(), shareContext.get(), GLVersion.major, GLVersion.minor, rendererID );
    } else {
        std::set<OSGLContextPtr>::iterator it = _imp->glContextPool.begin();
        newContext = *it;
        assert(newContext);
        _imp->glContextPool.erase(it);
    }
#else

    if ( (int)_imp->glContextPool.size() < maxContexts ) {
        //  Create a new one
        newContext = std::make_shared<OSGLContext>( FramebufferConfig(), shareContext.get(), GLVersion.major, GLVersion.minor, rendererID );
        _imp->glContextPool.insert(newContext);
    } else {
        while ((int)_imp->glContextPool.size() > maxContexts) {
            _imp->glContextPool.erase(_imp->glContextPool.begin());
        }

        // Cycle through all contexts for all renders
        OSGLContextPtr lastContext = _imp->lastUsedGLContext.lock();
        if (!lastContext) {
            newContext = *_imp->glContextPool.begin();
        } else {
            std::set<OSGLContextPtr>::iterator foundLast = _imp->glContextPool.find(lastContext);
            assert( foundLast != _imp->glContextPool.end() );
            if ( foundLast == _imp->glContextPool.end() ) {
                throw std::logic_error("No context to attach");
            } else {
                std::set<OSGLContextPtr>::iterator next = foundLast;
                ++next;
                if ( next == _imp->glContextPool.end() ) {
                    next = _imp->glContextPool.begin();