/**
* Finds the intersection point of a ray with the panel.
* The ray is defined by a point and a direction vector.
*@param A the ray's origin
*@param U the ray's direction
*@param I the intersection point
*@param dist the distance of A to the panel in the direction of the panel's normal
*/
bool Panel::Intersect(CVector const &A, CVector const &U, CVector &I, double &dist)
{
static CVector ILA, ILB, ITA, ITB;
static CVector T, V, W, P;
static bool b1, b2, b3, b4;
static double r,s;
ILA.Copy(s_pNode[m_iLA]);
ITA.Copy(s_pNode[m_iTA]);
ILB.Copy(s_pNode[m_iLB]);
ITB.Copy(s_pNode[m_iTB]);
r = (CollPt.x-A.x)*Normal.x + (CollPt.y-A.y)*Normal.y + (CollPt.z-A.z)*Normal.z ;
s = U.x*Normal.x + U.y*Normal.y + U.z*Normal.z;
dist = 10000.0;
if(qAbs(s)>0.0)
{
dist = r/s;
//inline operations to save time
P.x = A.x + U.x * dist;
P.y = A.y + U.y * dist;
P.z = A.z + U.z * dist;
// P is inside the panel if on left side of each panel side
W.x = P.x - ITA.x;
W.y = P.y - ITA.y;
W.z = P.z - ITA.z;
V.x = ITB.x - ITA.x;
V.y = ITB.y - ITA.y;
V.z = ITB.z - ITA.z;
T.x = V.y * W.z - V.z * W.y;
T.y = -V.x * W.z + V.z * W.x;
T.z = V.x * W.y - V.y * W.x;
if(T.x*T.x+T.y*T.y+T.z*T.z <1.0e-10 || T.x*Normal.x+T.y*Normal.y+T.z*Normal.z>=0.0) b1 = true; else b1 = false;
W.x = P.x - ITB.x;
W.y = P.y - ITB.y;
W.z = P.z - ITB.z;
V.x = ILB.x - ITB.x;
V.y = ILB.y - ITB.y;
V.z = ILB.z - ITB.z;
T.x = V.y * W.z - V.z * W.y;
T.y = -V.x * W.z + V.z * W.x;
T.z = V.x * W.y - V.y * W.x;
if(T.x*T.x+T.y*T.y+T.z*T.z <1.0e-10 || T.x*Normal.x+T.y*Normal.y+T.z*Normal.z>=0.0) b2 = true; else b2 = false;
W.x = P.x - ILB.x;
W.y = P.y - ILB.y;
W.z = P.z - ILB.z;
V.x = ILA.x - ILB.x;
V.y = ILA.y - ILB.y;
V.z = ILA.z - ILB.z;
T.x = V.y * W.z - V.z * W.y;
T.y = -V.x * W.z + V.z * W.x;
T.z = V.x * W.y - V.y * W.x;
if(T.x*T.x+T.y*T.y+T.z*T.z <1.0e-10 || T.x*Normal.x+T.y*Normal.y+T.z*Normal.z>=0.0) b3 = true; else b3 = false;
W.x = P.x - ILA.x;
W.y = P.y - ILA.y;
W.z = P.z - ILA.z;
V.x = ITA.x - ILA.x;
V.y = ITA.y - ILA.y;
V.z = ITA.z - ILA.z;
T.x = V.y * W.z - V.z * W.y;
T.y = -V.x * W.z + V.z * W.x;
T.z = V.x * W.y - V.y * W.x;
if(T.x*T.x+T.y*T.y+T.z*T.z <1.0e-10 || T.x*Normal.x+T.y*Normal.y+T.z*Normal.z>=0.0) b4 = true; else b4 = false;
if(b1 && b2 && b3 && b4)
{
I.Set(P.x, P.y, P.z);
return true;
}
}
return false;
}
