Question

I am trying to implement Bezier Curves for an assignment. I am trying to move a ball (using bezier curves) by giving my function an array of key frames. The function should give me all the frames in between the key frames … or control points … but although I’m using the formula found on wikipedia… it is not really working :s

her’s my code:

  private void interpolate(){
      float x,y,b, t = 0;
      frames = new Frame[keyFrames.length];
      for(int i =0;i<keyFrames.length;++i){   
         t+=0.001;
         b = Bint(i,keyFrames.length,t);   
         x = b*keyFrames[i].x;
         y = b*keyFrames[i].y;
         frames[i] = new Frame(x,y);     
      }
  }

private float Bint(int i, int n, float t){
  float Cni = fact(n)/(fact(i) * fact(n-i));
  return Cni * pow(1-t,n-i) * pow(t,i);
}

Also I’ve noticed that the frames[] array should be much bigger but I can’t find any other text which is more programmer friendly

Thanks in advance.

Answer 1

Finally got What I needed! Here’s what I did:

private void interpolate() {    
  float t = 0;
  float x,y,b;
  for(int f =0;f<frames.length;f++) {      
    x=0;
    y=0;
    for(int i = 0; i<keyFrames.length; i++) {       
      b = Bint(i,keyFrames.length-1,map(t,0,time,0,1));   
      x += b*keyFrames[i].x;
      y += b*keyFrames[i].y;
    }    
  frames[f] = new Frame(x,y); 
  t+=partialTime;     
}

}

private void createInterpolationData() {
     time = keyFrames[keyFrames.length-1].time -
     keyFrames[0].time;
     noOfFrames = 60*time;
     partialTime = time/noOfFrames;
     frames = new Frame[ceil(noOfFrames)];  
}