Method tick

native/cocos/engine/Engine.cpp:280–334

}

void Engine::tick() {
    CC_PROFILER_BEGIN_FRAME;
    {
        CC_PROFILE(EngineTick);

        _gfxDevice->frameSync();

        if (_needRestart) {
            doRestart();
            _needRestart = false;
        }

        static std::chrono::steady_clock::time_point prevTime;
        static std::chrono::steady_clock::time_point now;
        static float dt = 0.F;
        static double dtNS = NANOSECONDS_60FPS;

        ++_totalFrames;

        // iOS/macOS use its own fps limitation algorithm.
        // Windows for Editor should not sleep,because Editor call tick function synchronously
#if (CC_PLATFORM == CC_PLATFORM_ANDROID || (CC_PLATFORM == CC_PLATFORM_WINDOWS && !CC_EDITOR) || CC_PLATFORM == CC_PLATFORM_OHOS || CC_PLATFORM == CC_PLATFORM_OPENHARMONY || CC_PLATFORM == CC_PLATFORM_MACOS)
        if (dtNS < static_cast<double>(_preferredNanosecondsPerFrame)) {
            CC_PROFILE(EngineSleep);
            std::this_thread::sleep_for(
                std::chrono::nanoseconds(_preferredNanosecondsPerFrame - static_cast<int64_t>(dtNS)));
            dtNS = static_cast<double>(_preferredNanosecondsPerFrame);
        }
#endif

        events::BeforeTick::broadcast();

        prevTime = std::chrono::steady_clock::now();
        if (_xr) _xr->beginRenderFrame();
        _scheduler->update(dt);

        se::ScriptEngine::getInstance()->handlePromiseExceptions();
        events::Tick::broadcast(dt);
        se::ScriptEngine::getInstance()->mainLoopUpdate();

        cc::DeferredReleasePool::clear();
        if (_xr) _xr->endRenderFrame();
        
        // Executing async tasks at the end of the current frame to make the callback invoked as soon as possible.
        _scheduler->runFunctionsToBePerformedInCocosThread();
        
        now = std::chrono::steady_clock::now();
        dtNS = dtNS * 0.1 + 0.9 * static_cast<double>(std::chrono::duration_cast<std::chrono::nanoseconds>(now - prevTime).count());
        dt = static_cast<float>(dtNS) / NANOSECONDS_PER_SECOND;

        events::AfterTick::broadcast();
    }

    CC_PROFILER_END_FRAME;
}

void Engine::doRestart() {
    events::RestartVM::broadcast();