float fps = 60;
float targetDelta=1/fps; //this is the target time between each update//
float offset=0; //offset tracks how far away this gets from the target//
public void update(float delta){
	indexer++; //I assume the frame is timed correctly//
	offset+=(delta-targetDelta); //store the difference//
	while(offset<-targetDelta){ //and compensate//
		offset+=targetDelta;
		indexer--;
	}
	while(offset>targetDelta){
		offset-=targetDelta;
		indexer++;
	}
}