// Physics.cpp: implementation of the CPysics class.
//
//////////////////////////////////////////////////////////////////////

#include "Physics.h"

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CPhysics::CPhysics()
{

}

CPhysics::~CPhysics()
{

}

//---------------------------------------------------------------------
DWORD CPhysics::S2DGetDistance(CMyPos posBegin, CMyPos posEnd)
{
	return (DWORD)sqrt(
					(posBegin.x - posEnd.x) * 
					(posBegin.x - posEnd.x) +
					(posBegin.y - posEnd.y) *
					(posBegin.y - posEnd.y) 
				);
}
//---------------------------------------------------------------------
BOOL CPhysics::S2DBMGetPos(int nV, float fA, float fT, CMyPos posBegin, CMyPos posEnd, CMyPos& posCurrent)
{
	double dwDistance = sqrt(
		(posBegin.x - posEnd.x) * 
		(posBegin.x - posEnd.x) +
		(posBegin.y - posEnd.y) *
		(posBegin.y - posEnd.y) 
				);
	if(dwDistance == 0)
	{
		posCurrent = posEnd;
		return true;
	}

	double nCompleteDistance = (int)(nV * fT + fA * fT * fT / 2);
	if(nCompleteDistance >= dwDistance)
	{
		posCurrent = posEnd;
		return true;
	}

	// Get Currentpos
	double dX = posBegin.x + (posEnd.x - posBegin.x) * nCompleteDistance / dwDistance;
	double dY = posBegin.y + (posEnd.y - posBegin.y) * nCompleteDistance / dwDistance;

	posCurrent.x = ::Double2Int(dX);
	posCurrent.y = ::Double2Int(dY);
	return false;
}
//---------------------------------------------------------------------
void CPhysics::S3Get3DDir(CMy3DPos posBegin, CMy3DPos posEnd, CMy3DDir& dir3D)
{
// 計算平行角度
	double fPei=3.14159;
	// 計算夾角先
	int nOffsetX = posEnd.x-posBegin.x;
	if(nOffsetX == 0)
		nOffsetX = 1;
	double fTan = (posEnd.y-posBegin.y)*1.0/nOffsetX;
	if(fTan < 0)
		fTan = -fTan;

	double fHorizontal = atan(fTan);	

	// 判斷在哪個象限，取附加數(shù)值
	int nX = posEnd.x - posBegin.x;
	int nY = posEnd.y - posBegin.y;
	if((nX > 0) && (nY < 0))
	{
		// 第一象限
		dir3D.fHorizontal = (float)(fHorizontal + fPei/2);
	}
	else if((nX < 0) && (nY >= 0))
	{
		// 第二象限
		dir3D.fHorizontal = (float)(fHorizontal - fPei/2);
	}
	else if((nX < 0) && (nY < 0))
	{
		// 第三象限
		dir3D.fHorizontal = (float)(-fPei/2 - fHorizontal);
	}
	else
	{
		// 第四象限
		dir3D.fHorizontal = (float)(fPei/2 - fHorizontal);
	}

// 計算垂直角度
	// 計算夾角先          
	fTan = abs(posEnd.z-posBegin.z)/sqrt((posEnd.y-posBegin.y)*(posEnd.y-posBegin.y) + (posEnd.x-posBegin.x)*(posEnd.x-posBegin.x));
	double fVertical = atan(fTan);

	// 判斷在哪個象限，取附加數(shù)值
	int nZ = posEnd.z-posBegin.z;
	if(nZ >=0 )
		dir3D.fVertical = (float)fVertical;
	else
		dir3D.fVertical = (float)(-fVertical);
}
//---------------------------------------------------------------------
BOOL CPhysics::IsPointInRect(CMyPos posPoint, CMyRect rect)
{
	if((posPoint.x >= rect.l) &&
	   (posPoint.x <= rect.r) &&
	   (posPoint.y >= rect.b) &&
	   (posPoint.y <= rect.t))
	   return true;
	return false;
}
//---------------------------------------------------------------------
void CPhysics::S2DR45VP(CMyPos posTarget, CMyPos& posPoint)
{
	CMyPos posRule={0, 32};

	// 真實長度在 32 和 16 之間
	// 先求真實長度RealDistance
	// 為求真實長度必須求和X軸夾角,用偽橢圓近似
	float fTag = 0.0;
	if(posTarget.x == 0)
		fTag = 0.0;
	else if(posTarget.y == 0)
		fTag = 2.0;
	else 
		fTag = (float)(1.0*posTarget.x/posTarget.y);

	if(fTag < 0)
		fTag = -fTag;
	if(fTag > 2.0)
		fTag = 2.0;
	float fDistance = (float)sqrt(posTarget.x*posTarget.x + posTarget.y*posTarget.y);
	// 靠近0為16， 靠近2.0為32
	float fRealDistance = (float)(16 + 16*fTag*1.0/2);
	CMyPos posRealTarget;

	// 求終點
	if((posTarget.x == 0)&&(posTarget.y != 0))
	{
		posRealTarget.x = 0;
		posRealTarget.y = (int)((posTarget.y/abs(posTarget.y))*fRealDistance);
	}
	else if((posTarget.y == 0)&&(posTarget.x != 0))
	{
		posRealTarget.y = 0;
		posRealTarget.x = (int)((posTarget.x/abs(posTarget.x))*fRealDistance);
	}
	else if((posTarget.y == 0)&&(posTarget.x == 0))
	{
		posRealTarget.x = 0;
		posRealTarget.y = 0;
	}
	else
	{
		posRealTarget.x = (int)(1.0*posTarget.x*fRealDistance/fDistance);
		posRealTarget.y = (int)(1.0*posTarget.y*fRealDistance/fDistance);
	}
	// 求映射點
	float fScale = (float)(posPoint.x*1.0/32);
	if(fScale < 0)
		fScale = -fScale;
	posPoint.x = (int)(posRealTarget.x * fScale);
	posPoint.y = (int)(posRealTarget.y * fScale);
}
//---------------------------------------------------------------------
BOOL CPhysics::S2DCMGetPos(int nV, float fA, float fT, float fRadii, CMyPos posBegin, CMyPos posEnd, CMyPos& posCurrent, BOOL bSide)
{
	// Calculate the shortest distance from begin position to end position
	double dDistance = sqrt( (posBegin.x - posEnd.x) * (posBegin.x - posEnd.x) + (posBegin.y - posEnd.y) * (posBegin.y - posEnd.y) );
	if ( dDistance == 0 )
	{
		posCurrent = posEnd;
		return true;
	}
	
	// Calculate the complete distance(The V&A are beeline, only the move track is curve)
	double dCompleteDistance = (int)( nV * fT + fA * fT * fT / 2 );
	if ( dCompleteDistance >= dDistance )
	{
		posCurrent = posEnd;
		return true;
	}
	
	// Calculate the curve offset from the shortest path
	double dLongRadii	= (int)( dDistance / 2 );
	double dShortRadii	= (int)( fRadii * dLongRadii );
	double dwCurveDistance = sqrt( dShortRadii * dShortRadii - ( dShortRadii * dShortRadii * ( dLongRadii - dCompleteDistance  ) * ( dLongRadii - dCompleteDistance ) ) / ( dLongRadii * dLongRadii ) );
	
	// The X axis and Y axis offset on the shortest path
	double dX = ( posEnd.x - posBegin.x ) * dCompleteDistance / dDistance;
	double dY = ( posEnd.y - posBegin.y ) * dCompleteDistance / dDistance;
	
	// Calculate the angle
	double dAngle = atan( dY / dX );
	
	if ( bSide )
	{
		dX -= sin(dAngle) * dwCurveDistance;
		dY += cos(dAngle) * dwCurveDistance;
	}
	else
	{
		dX += sin(dAngle) * dwCurveDistance;
		dY -= cos(dAngle) * dwCurveDistance;
	}
	
	dX += posBegin.x;
	dY += posBegin.y;
	
	posCurrent.x = ::Double2Int(dX);
	posCurrent.y = ::Double2Int(dY);
	return false;
}
//---------------------------------------------------------------------