我正在尝试向我的班级添加旋转函数,以绕X,Y,Z轴旋转,但是输出与我期望的不完全相同
我确保我的公式正确,它们似乎正确,但我不知道。我从中得到他们:Rotating a Vector in 3D Space
#include <iostream>
using namespace std;
#include <math.h>
// Vector class, to handle all the vector operations for us
// Thanks to : https://stackoverflow.com/questions/14607640/rotating-a-vector-in-3d-space
class cVector
{
public:
float x;
float y;
float z;
// Constructor
cVector();
cVector(float x1, float y1, float z1);
// returns the vector's magnitude
float Magnitude();
// Normalize ( change length to 1, while keeping the same direction)
void Normalize();
// Rotate around the Axis
void RotateX(float angle);
void RotateY(float angle);
void RotateZ(float angle);
// TODO : Add operators for Addition & Substraction
// Addition
cVector operator+(cVector const& v1) const
{
return cVector(x + v1.x,
y + v1.y,
z + v1.z);
}
void operator+=(cVector const& v1)
{
x += v1.x;
y += v1.y;
z += v1.z;
}
// Substraction
cVector operator-(cVector const& v1) const
{
return cVector(x - v1.x,
y - v1.y,
z - v1.z);
}
void operator-=(cVector const& v1)
{
x -= v1.x;
y -= v1.y;
z -= v1.z;
}
// Multiplication
void operator*=(const float scalar)
{
x *= scalar;
y *= scalar;
z *= scalar;
}
cVector operator*(const float scalar) const
{
return cVector(x * scalar,
y * scalar,
z * scalar);
}
// Division
void operator/=(const float scalar)
{
x /= scalar;
y /= scalar;
z /= scalar;
}
cVector operator/(const float scalar) const
{
return cVector(x / scalar,
y / scalar,
z / scalar);
}
};
// Constructor
cVector::cVector()
{
}
cVector::cVector(float x1, float y1, float z1)
{
x = x1;
y = y1;
z = z1;
}
// returns the vector's magnitude
float cVector::Magnitude()
{
return sqrt((x * x) + (y * y) + (z * z));
}
// Normalize ( change length to 1, while keeping the same direction)
void cVector::Normalize()
{
float flMagnitude = Magnitude();
// We devide the coordinates by the magnitude
x /= flMagnitude;
y /= flMagnitude;
z /= flMagnitude;
}
// Rotate around the Axis
void cVector::RotateX(float angle)
{
y = y * cos(angle) - z * sin(angle);
z = y * sin(angle) + z * cos(angle);
}
void cVector::RotateY(float angle)
{
x = (x * cos(angle)) + (z * sin(angle));
z = (-x * sin(angle)) + (z * cos(angle));
}
void cVector::RotateZ(float angle)
{
x = x * cos(angle) - y * sin(angle);
y = x * sin(angle) + y * cos(angle);
}
void PrintVector(cVector vec)
{
cout << "X : " << vec.x << " Y : " << vec.y << " Z : " << vec.z << endl;
}
// TODO : Add operators for Addition & Substraction
int main()
{
cout << "Hello world!" << endl;
cVector vec(10, 0, 0);
vec.RotateZ(1.57f);
PrintVector(vec);
cin.get();
return 0;
}
我希望该方法保持向量的大小不变,并返回(0,10,0),因为我旋转pi / 2,但这不是我得到的。显然,如果我按pi旋转,我会得到很好的结果,但是除此之外,它不起作用。
答案 0 :(得分:1)
首先在RotateZ中进行旋转,例如,应将x保存在一些临时位置,因为如果您对其进行修改,然后尝试将其用于y,则显然会导致错误,即应执行以下操作>
void cVector::RotateZ(float angle)
{
float temp = x;
x = x * cos(angle) - y * sin(angle);
y = temp * sin(angle) + y * cos(angle);
}
第二个给定的pi值太舍入,因此值为false
您可以为pi值做类似的事情
const float Pi = 3.1415926535;