mathutils.h

来自「Symbian s60 游戏编程示例」· C头文件 代码 · 共 117 行

#ifndef __MATH_UTILS_H
#define __MATH_UTILS_H

#include <e32math.h>

// __USE_TLS should be enabled if project is built as an APP (DLL)
// It should be disabled for an EXE
// #define __USE_TLS


//
// Static class of utils
//

/*
 * Pregenerated sin and cos tables
 */

#include "sincostables.h"

/*
 MathUtils - For when Math is just not fast enoug
*/
class MathUtils
	{
public:

	// Fast Square root 
	static TInt32 SquareRoot(TInt32 aNum);

	// Distance between two integer points
	static TInt Distance(const TPoint& aA, const TPoint& aB);
	inline static TReal Sin(TReal aNumber);
	inline static TReal Cos(TReal aNumber); 

	// Fast Cos for whole angles between 0 and 360
	static inline TReal Cos(TInt aAngle); 

	// Fast Sin for whole angles between 0 and 360
	static inline TReal Sin(TInt aAngle); 
	// Fast Cos for whole angles between 0 and 360 

	static void ConstructL();
	static inline TInt Round(TReal aNumber);
	inline static TInt Random(TInt aA, TInt aB);

	// return x bounded between a and b
	template<class T>
	inline T Bound(T x, T a, T b);
	
	static void Reset();	
	static TBool Intersect(TPoint l1p1, TPoint l1p2, TPoint l2p1, TPoint l2p2);
	};


inline TReal MathUtils::Sin(TReal aNumber)
	{
	TReal result;
	Math::Sin(result, aNumber);
	return result;
	}
inline TReal MathUtils::Cos(TReal aNumber) 
	{
	TReal result;
	Math::Cos(result, aNumber);
	return result;
	}	

/*
	Fast Cos for whole angles between 0 and 360
*/	
inline TReal MathUtils::Cos(TInt aAngle)  
	{
	return KCosLookup[aAngle%360];
	}

/*
	Fast Sin for whole angles between 0 and 360
*/
inline TReal MathUtils::Sin(TInt aAngle) 
	{
	return KSinLookup[aAngle%360];
	}

/*
	Faster replacement for Math::Round
*/ 
inline TInt MathUtils::Round(TReal aNumber)
	{
	TInt whole = (TInt)aNumber;
	TReal frac = aNumber-whole;
	if(frac>=0.5)
		return whole+1;
	else
		return whole;
	}

// Random number between a and b
TInt MathUtils::Random(TInt aA, TInt aB)
	{
	if(aA == aB)
		return aA;
	
	return Math::Random()%(aB - aA) + aA;
	}

// return x bounded between a and b
template<class T>
T MathUtils::Bound(T x, T a, T b)
	{
	if(x<a) x=0;
	if(x>b) x=b;
	return x;
	}

#endif