// description of your code here
Usage:

Initialization:
SmoothMove* sm = new SmoothMove(start,end,0.1,SmoothMove::DescQuadraticMethod);

Every frame:
Vector3 currentPosition = sm->IterateFrame(evt.timeSinceLastFrame);

If you want to change the target at midflight:
Vector3 newTarget(0.5,2.0,0.1); // the new target position
sm->SetNewTarget(newTarget,0.4); // give it 0.4 seconds to go there

   1  
   2  #include "smoothMove.h"
   3  
   4  SmoothMove::SmoothMove(const Vector3 &start, const Vector3 &end, const float time,float (*smoothMethod)(float)): 
   5  	mStart(start), mEnd(end), mTotalTime(time),mCurrentMethod(smoothMethod)
   6  {
   7  	mCurrentTime = 0;
   8  	mCurrent = mStart;
   9  }
  10  	
  11  Vector3 SmoothMove::IterateFrame(const float time)
  12  {
  13  	mCurrentTime+=time;
  14  	if(mCurrentTime>mTotalTime)
  15  		mCurrentTime=mTotalTime;
  16  	return CalculateCurrentPos();
  17  }
  18  
  19  Vector3 SmoothMove::CalculateCurrentPos()
  20  {
  21  	mCurrent.x = CalculatePos(mStart.x,mEnd.x,mCurrentTime,mTotalTime);
  22  	mCurrent.y = CalculatePos(mStart.y,mEnd.y,mCurrentTime,mTotalTime);
  23  	mCurrent.z = CalculatePos(mStart.z,mEnd.z,mCurrentTime,mTotalTime);
  24  	
  25  	return mCurrent;
  26  }
  27  
  28  void SmoothMove::SetNewTarget(const Vector3 &end, const float time)
  29  {
  30  	mStart = mCurrent;
  31  	mEnd = end;
  32  	mCurrentTime = 0;
  33  	mTotalTime = time;
  34  }
  35  
  36  bool SmoothMove::isEqual(float x, float y)
  37  {
  38  	return abs(x-y)<0.000000001;
  39  }
  40  
  41  float SmoothMove::CalculatePos(float start, float end,float currentTime, float totalTime)
  42  {
  43  	// we transform the currentTime value into a (0,1) range value that 
  44  	// indicates the ammount of the travel we've done so far
  45  	float x = 1-(totalTime-currentTime)/totalTime;
  46  	
  47  	// we make sure the method gives valid results at least for the beggining and end
  48  	assert(isEqual((*mCurrentMethod)(0),0));
  49  	assert(isEqual((*mCurrentMethod)(1),1));
  50  
  51  	// We interpolate the value
  52  	float current = (*mCurrentMethod)(x);
  53  	
  54  	// we go back from (0,1) range to (start, end) range
  55  	current=current*(end-start)+start;
  56  
  57  	return current;
  58  }

// description of your code here
It uses Ogre, but only for the Vector3 class.

   1  
   2  #ifndef SMOOTHMOVE_H
   3  #define SMOOTHMOVE_H
   4  #include <Ogre/Ogre.h>
   5  #include <cmath>
   6  
   7  using namespace Ogre;
   8  
   9  // Class to interpolate the points in a path defined by 2 points (start and end)
  10  // There are several methods to do the interpolation (linear, spherical, halfsinus, etc)
  11  // You can add methods just by definig another method in this class. The only requirements
  12  // are that they take a float parameter, return a float, and that for x=0 they return 0, and
  13  // for x=1 they return 1 
  14  
  15  class SmoothMove
  16  {
  17  	private:
  18  		Vector3 mStart;
  19  		Vector3 mEnd;
  20  		float mTotalTime;
  21  		
  22  		float mCurrentTime;
  23  		Vector3 mCurrent;
  24  		float (*mCurrentMethod)(float);
  25  		float CalculatePos(float start, float end,float currentTime, float totalTime);
  26  		static bool isEqual(float x, float y);
  27  
  28  	public:
  29  		SmoothMove(const Vector3 &start, const Vector3 &end,const float time,float (*smoothMethod)(float));
  30  		Vector3 IterateFrame(const float time);
  31  		Vector3 CalculateCurrentPos();
  32  		void SetNewTarget(const Vector3 &end,const float time);
  33  
  34  		static float LinearMethod(float x) { return x; }
  35  		static float AscQuadraticMethod(float x){ return x*x; }	
  36  		static float DescQuadraticMethod(float x){ return 1-(x-1)*(x-1); }
  37  		static float HalfSinusMethod(float x){ return sin(x*M_PI/2); }
  38  		static float SphericalMethod(float x){ return sqrt(1-(x-1)*(x-1)); }
  39  		static float SmoothSinus(float x){ return sin(M_PI*(x-0.5))*3/2; }
  40  };
  41  
  42  #endif