public float getCurrent(int now) {
		  switch (mType)
		  {
		  case 0:
			   return mStartValue;

		  case 1:
			   if (now <= mStartTime)
					return mStartValue;
			   else if (now >= mEndTime)
					return mEndValue;
			   else return
						 (mEndValue * (now - mStartTime) +
						  mStartValue * (mEndTime - now)) /
						 (mEndTime - mStartTime);
					
		  case 2:
			   if (now <= mStartTime)
					return mStartValue;
			   else return mStartValue +
						 mEndValue *
						 (now - mStartTime) / mEndTime;
		  default:
			   return 0;
		  }
	 }