C++11_openframeworks_tween_util_class

C++11_openframeworks_tween_util_class.h

#include "ofMain.h"

class Utils
{
public:
    static void tween(float start_val, float end_val, int interval, std::function<void(float)> task, std::function<void()> complete = [](){})
    {
        auto start_time = std::chrono::system_clock::now();
        std::thread([start_val, end_val, interval, start_time, task, complete]() {
            while(true)
            {
                auto end_time = std::chrono::system_clock::now() ;
                auto elapsed = std::chrono::duration_cast< std::chrono::milliseconds >( end_time - start_time);
                if( interval <= elapsed.count() )
                {
                    task(end_val);
                    complete();
                    break;
                }
                float tt = start_val + (end_val - start_val) * elapsed.count() / interval;
                task(tt);
                std::this_thread::sleep_for(std::chrono::milliseconds(1000/30));
            }
        }).detach();
    }
    
    static void later(int interval, bool async, std::function<void()> task)
    {
        if (async)
        {
            std::thread([interval, task]() {
                std::this_thread::sleep_for(std::chrono::milliseconds(interval));
                task();
            }).detach();
        }
        else
        {
            std::this_thread::sleep_for(std::chrono::milliseconds(interval));
            task();
        }
    }
};


class ofApp : public ofBaseApp
{
public:
    int _hue = 0;
    void setup()
    {
        ofSetColor(255);
        ofBackground(0);
        ofSetCircleResolution(50);
    }
    
    
    void draw()
    {
        ofSetColor( ofColor::fromHsb( _hue, 255, 255 ) );
        ofDrawCircle(ofGetWidth()*0.5, ofGetHeight()*0.5, sin(ofGetElapsedTimeMillis()*0.005)*100.0);
    }
    
    void keyPressed(int key)
    {
        switch(key)
        {
            case '1':
            {
                Utils::tween(0, 255, 2000, [&](float val){
                    _hue = val ;
                    cout << "tween hue:" << _hue <<  endl;
                });
                
                break;
            }
                
            case '2':
            {
                Utils::tween(0, 255, 2000, [&](float val){
                    _hue = val ;
                    cout << "tween hue:" << _hue <<  endl;
                }, [&](){
                    _hue = 100;
                    cout << "end tween" << endl;
                });
                
                break;
            }
                
            case '3':
            {
                Utils::later(1000, true, [&](){
                    _hue += 30;
                    cout << "later:" << _hue <<  endl;
                });
                
                break;
            }
        }
    }
};


int main( )
{
	ofSetupOpenGL(500,500,OF_WINDOW);
	ofRunApp(new ofApp());
}