MathUtil.h

[詳解]

#ifndef __MATHUTIL_H__
#define __MATHUTIL_H__

#define _USE_MATH_DEFINES
#include <math.h>
#include "Vector3D.h"

// 演算関係.
class MathUtil
{

public:

    // 補間.
    template<class T>
    static T Lerp(T Start, T End, float Rate);

    // DegreeをRadianに変換.
    static float DegToRad(float Deg)
    {
        if (fabsf(Deg) < FLT_EPSILON) { return 0.0f; }
        return (float)(Deg * M_PI / 180.0f);
    }

    // RadianをDegreeに変換.
    static float RadToDeg(float Rad)
    {
        if (fabsf(Rad) < FLT_EPSILON) { return 0.0f; }
        return (float)(Rad * 180.0f / M_PI);
    }

    // ベクトルを回転.
    static Vector3D RotateVector(const Vector3D &Vec, float Deg)
    {
        Vector3D Result;
        float Rad = DegToRad(Deg);
        Result.X = ((Vec.X * cosf(Rad)) - (Vec.Y * sinf(Rad)));
        Result.Y = ((Vec.X * sinf(Rad)) + (Vec.Y * cosf(Rad)));
        Result.Z = Vec.Z;
        return Result;
    }

    // 内積.
    static float Dot(const Vector3D &A, const Vector3D &B)
    {
        return ((A.X * B.X) + (A.Y * B.Y) + (A.Z * B.Z));
    }

    // 外積.
    static Vector3D Cross(const Vector3D &A, const Vector3D &B)
    {
        Vector3D Vec;
        Vec.X = (A.Y * B.Z) - (A.Z * B.Y);
        Vec.Y = (A.Z * B.X) - (A.X * B.Z);
        Vec.Z = (A.X * B.Y) - (A.Y * B.X);
        return Vec;
    }

};

#endif      // #ifndef __MATHUTIL_H__