[英]Multiply vec3 with mat4 using glm
此刻,我将vec3
转换为vec4
,将其与矩阵相乘,然后将其转换回vec3
码:
glm::vec3 transformed = glm::vec3(matrix * glm::vec4(point, 0.0))
它有效,但我认为这不是计算它的好方法。 是否可以在vec3
上应用mat4
,而不将其转换为vec4
并返回?
mat4是一个4乘4的矩阵,所以你需要一个4维向量来乘以它。
第四维对于3D数学非常有用,可以区分3D空间点(1)和3D矢量(0)
在这里,我错过了许多操作员,但我希望你能得到这个想法。
class point3
{
public:
vec4 p;
public:
point3();
point3(const point3& rhs);
point3(const point3& rhs);
point3(float x, float y, float z);
point3& operator=(const point3&rhs);
vector3 operator-(const point3&rhs);
point3 operator+(const vector3&rhs);
point3& operator+=(const vector3&rhs);
};
point3::point3():p.x(0), p.y(0), p.z(0), p.w(1)
{
}
point3::point3(const point3& rhs):p(rhs.p)
{
}
point3::point3(const point3& rhs):p(rhs.p)
{
}
point3::point3(float x, float y, float z):p.x(x), p.y(y), p.z(z), p.w(1)
{
}
point3& point3::operator=(const point3&rhs)
{
return (p=rhs.p);
}
vector3 point3::operator-(const point3&rhs)
{
vector3 result;
result.p=(p-rhs.p);
return result;
}
point3 point3::operator+(const vector3&rhs)
{
point3 result;
result.p=(p+rhs.p);
return result;
}
point3& point3::operator+=(const vector3&rhs)
{
p=(p+rhs.p);
return p;
}
class vector3
{
public:
vec4 p;
public:
vector3();
vector3(const vector3& rhs);
vector3(const vector3& rhs);
vector3(float x, float y, float z);
vector3& operator=(const vector3&rhs);
vector3 operator-(const vector3&rhs);
point3 operator-(const point3&rhs);
point3 operator+(const point3&rhs);
vector3 operator+(const vector3&rhs);
vector3& operator+=(const vector3&rhs);
};
vector3::vector3():p.x(0), p.y(0), p.z(0), p.w(0)
{
}
vector3::vector3(const vector3& rhs):p(rhs.p)
{
}
vector3::vector3(const vector3& rhs):p(rhs.p)
{
}
vector3::vector3(float x, float y, float z):p.x(x), p.y(y), p.z(z), p.w(0)
{
}
vector3& vector3::operator=(const vector3&rhs)
{
p=rhs.p;
return p;
}
vector3 vector3::operator-(const vector3&rhs)
{
vector3 result;
result.p=(p-rhs.p);
return result;
}
point3 vector3::operator-(const point3&rhs)
{
point3 result;
result.p=(p-rhs.p);
return result;
}
point3 vector3::operator+(const point3&rhs)
{
point3 result;
result.p=(p+rhs.p);
return result;
}
vector3 vector3::operator+(const vector3&rhs)
{
vector3 result;
result.p=(p+rhs.p);
return result;
}
vector3& vector3::operator+=(const vector3&rhs)
{
p=(p+rhs.p);
return p;
}
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