void FDice::create(const XYZ& p0, const XYZ& p1, const XYZ& p2)
{
p_obj[0] = P[0] = p0;
p_obj[1] = P[1] = p1;
p_obj[2] = P[2] = p2;
V[0] = p1 - p0;
edge_length[0] = V[0].length();
V[1] = p2 - p1;
edge_length[1] = V[1].length();
V[2] = p0 - p2;
edge_length[2] = V[2].length();
area = 0.5*sqrt(edge_length[0]*edge_length[0]*edge_length[2]*edge_length[2] - (V[0].dot(V[2]))*(V[0].dot(V[2])));
V[0].normalize();
V[1].normalize();
V[2].normalize();
int a , b;
if(edge_length[0] > edge_length[1] && edge_length[0] > edge_length[2])
{
a = 0;
b = 1;
}
else if(edge_length[1] > edge_length[2] && edge_length[1] > edge_length[0])
{
a = 1;
b = 2;
}
else
{
a = 2;
b = 0;
}
XYZ side = V[a];
XYZ front = side^V[b]; front.normalize();
XYZ up = front^side;
m_space.setOrientations(side, up, front);
m_space.setTranslation(P[a]);
m_space.inverse();
m_space.transform(p_obj[0]);
m_space.transform(p_obj[1]);
m_space.transform(p_obj[2]);
f120 = barycentric_coord(p_obj[1].x, p_obj[1].y, p_obj[2].x, p_obj[2].y, p_obj[0].x, p_obj[0].y);
f201 = barycentric_coord(p_obj[2].x, p_obj[2].y, p_obj[0].x, p_obj[0].y, p_obj[1].x, p_obj[1].y);
f012 = barycentric_coord(p_obj[0].x, p_obj[0].y, p_obj[1].x, p_obj[1].y, p_obj[2].x, p_obj[2].y);
}
// rotar p con eje de rotacion r
XYZ rotate(XYZ p, XYZ r, double theta){
XYZ q(0,0,0);
double costheta,sintheta;
r.normalize();
costheta = cos(theta);
sintheta = sin(theta);
q.x += (costheta + (1 - costheta) * r.x * r.x) * p.x;
q.x += ((1 - costheta) * r.x * r.y - r.z * sintheta) * p.y;
q.x += ((1 - costheta) * r.x * r.z + r.y * sintheta) * p.z;
q.y += ((1 - costheta) * r.x * r.y + r.z * sintheta) * p.x;
q.y += (costheta + (1 - costheta) * r.y * r.y) * p.y;
q.y += ((1 - costheta) * r.y * r.z - r.x * sintheta) * p.z;
q.z += ((1 - costheta) * r.x * r.z - r.y * sintheta) * p.x;
q.z += ((1 - costheta) * r.y * r.z + r.x * sintheta) * p.y;
q.z += (costheta + (1 - costheta) * r.z * r.z) * p.z;
return q;
}