Simple Motion blur by (Keijiro Takahashi) rewritten in c++

main.cpp

/*

Rewritten Code by Keijiro Takahashi 

source:
https://github.com/keijiro/sketches2016/blob/master/Moblur/Moblur.pde

*/

#include "ofMain.h"

#define N 13
class ofApp : public ofBaseApp{
        public:
                float gaussian[N];

                float position(float t)
                {
                          return (1.0 - cos(PI * 2 * t)) * 0.5;
                }

                void setup()
                {
                          float sum = 0.0;
                          for (int i = 0; i < N; i++)
                          {
                              float d = (i + 0.5) * 2 / N - 1;
                              gaussian[i] = exp(-1.5 * d * d);
                              sum += gaussian[i];
                          }
                          for (int i = 0; i < N; i++)
                              gaussian[i] /= sum;
                }

                void update()
                {
                        ofSetWindowTitle(ofToString(ofGetFrameRate()));
                }

                void draw()
                {
                        float totalFrames = 13;
                        float t = (float)ofGetFrameNum() / totalFrames;
                        float delta = 1.0 / totalFrames;
                        if (ofGetFrameNum() > totalFrames * 2)
                            t = round((ofGetFrameNum() - totalFrames * 2) / 5) / totalFrames;

                        ofBackground(255);
                        drawBall(position(t), 100, 100, ofColor(0,0,0,255));

                        for (int i = 0; i < N; i++)
                        {
                           float dt = ((i + 0.5) / N - 0.5) * delta;
                           float w1 = 1.0 / N;
                           float w2 = (i + 0.5) * 2.0 / N;
                           if (w2 > 1) w2 = 2 - w2;
                           w2 *= 2.0 / N;
                           float w3 = gaussian[i];

                           drawBall(position(t + dt), 200, 100, ofColor(255,0,0,ofMap(w1,0.,1.,0,255)));
                           drawBall(position(t + dt), 300, 100, ofColor(0,255,0,ofMap(w2,0.,1.,0,255)));
                           drawBall(position(t + dt), 400, 100, ofColor(0,0,255,ofMap(w3,0.,1.,0,255)));
                        }
                }
        
                void drawBall(float x, float y, float w, ofColor color)
                {
                          x = ofLerp(0.1, 0.95, x) * ofGetWidth();
                          ofSetColor(color);
                          ofDrawEllipse(x, y, w, w);
                }
};

int main(){
        ofSetupOpenGL(1024,768, OF_WINDOW);
        ofRunApp( new ofApp());
}