2D向量点乘自身代表什么意思？

tracegame

1. 
   
2. // two objects collided at time t. stop them at that time
   
3. void CBody::ProcessCollision(CBody& xBody, const Vector& N, float t)
   
4. {
   
5.         Vector D = m_xDisplacement - xBody.m_xDisplacement;
   
6. 
   
7.         float n  = D * N;
   
8.        
   
9.         Vector Dn = N * n;
   
10.         Vector Dt = D - Dn;
    
11. 
    
12. //上面这三句是在干什么？n求的是什么？Dn和Dt求的又是什么？
    
13.        
    
14.         if (n > 0.0f) Dn = Vector(0, 0);
    
15. 
    
16.         float dt  = Dt * Dt;//这里什么意思？*是点乘重载，Vector是2D向量
    
17.         float CoF = s_fFriction;
    
18.        
    
19.         if (dt < s_fGlue*s_fGlue) CoF = 1.01f;
    
20. 
    
21.         D = -(1.0f + s_fRestitution) * Dn - (CoF) * Dt;
    
22. 
    
23.         float m0 =       GetInvMass();
    
24.         float m1 = xBody.GetInvMass();
    
25.         float m  = m0 + m1;
    
26.         float r0 = m0 / m;
    
27.         float r1 = m1 / m;
    
28.        
    
29.         m_xDisplacement += D * r0;
    
30.         xBody.m_xDisplacement -= D * r1;
    
31. }
    

复制代码

tracegame

这排版真是太恐怖了.........还是直接贴吧

// two objects collided at time t. stop them at that time
void CBody:rocessCollision(CBody& xBody, const Vector& N, float t)
{
        Vector D = m_xDisplacement - xBody.m_xDisplacement;

        float n  = D * N;
       
        Vector Dn = N * n;
        Vector Dt = D - Dn;
       
        if (n > 0.0f) Dn = Vector(0, 0);

        float dt  = Dt * Dt;
        float CoF = s_fFriction;
       
        if (dt < s_fGlue*s_fGlue) CoF = 1.01f;

        D = -(1.0f + s_fRestitution) * Dn - (CoF) * Dt;

        float m0 =       GetInvMass();
        float m1 = xBody.GetInvMass();
        float m  = m0 + m1;
        float r0 = m0 / m;
        float r1 = m1 / m;
       
                  m_xDisplacement += D * r0;
        xBody.m_xDisplacement -= D * r1;
}

Chang_back

点乘可以求出第三维的向量！

SITT

楼上说的是叉乘

Devil

意义就是求出  X*X + Y*Y 等于多少