Method aboutToStartRender

Engine/OutputSchedulerThread.cpp:2546–2621

}

void
DefaultScheduler::aboutToStartRender()
{
    boost::shared_ptr<OutputSchedulerThreadStartArgs> args = getCurrentRunArgs();
    boost::shared_ptr<OutputEffectInstance> effect = _effect.lock();

    {
        QMutexLocker k(&_currentTimeMutex);
        if (args->pushTimelineDirection == eRenderDirectionForward) {
            _currentTime  = args->firstFrame;
        } else {
            _currentTime  = args->lastFrame;
        }
    }
    bool isBackGround = appPTR->isBackground();

    if (!isBackGround) {
        effect->setKnobsFrozen(true);
    } else {
        QString longText = QString::fromUtf8( effect->getScriptName_mt_safe().c_str() ) + tr(" ==> Rendering started");
        appPTR->writeToOutputPipe(longText, QString::fromUtf8(kRenderingStartedShort), true);
    }

    // Activate the internal writer node for a write node
    WriteNode* isWriter = dynamic_cast<WriteNode*>( effect.get() );
    if (isWriter) {
        isWriter->onSequenceRenderStarted();
    }

    std::string cb = effect->getNode()->getBeforeRenderCallback();
    if ( !cb.empty() ) {
        std::vector<std::string> args;
        std::string error;
        try {
            NATRON_PYTHON_NAMESPACE::getFunctionArguments(cb, &error, &args);
        } catch (const std::exception& e) {
            effect->getApp()->appendToScriptEditor( std::string("Failed to run beforeRender callback: ")
                                                    + e.what() );

            return;
        }

        if ( !error.empty() ) {
            effect->getApp()->appendToScriptEditor("Failed to run beforeRender callback: " + error);

            return;
        }

        std::string signatureError;
        signatureError.append("The beforeRender callback supports the following signature(s):\n");
        signatureError.append("- callback(thisNode, app)");
        if (args.size() != 2) {
            effect->getApp()->appendToScriptEditor("Failed to run beforeRender callback: " + signatureError);

            return;
        }

        if ( (args[0] != "thisNode") || (args[1] != "app") ) {