分形之螺线

 1 void        CFractalHelix::FractalHelix(const Vector3& vStart, const Vector3& vEnd, Vector3* pVertices)
 2 {
 3     Vector3 vDir = vEnd - vStart;
 4     float len = D3DXVec3Length(&vDir);
 5     float radius = len*m_params[0];
 6 
 7     float xz = sqrtf(vDir.x*vDir.x + vDir.z*vDir.z);
 8     float angleY = atan2f(xz, vDir.y);
 9     float angleXZ = atan2f(vDir.x, vDir.z);
10 
11     float e = sin(angleY);
12     float f = cos(angleY);
13 
14     float g = sin(angleXZ);
15     float h = cos(angleXZ);
16 
17     for (int i = 0; i < CIRCLE_POINTS_COUNT; i++)
18     {
19         pVertices[i] = vStart + vDir*(i*1.0f/CIRCLE_POINTS_COUNT);
20 
21         float x0 = m_vSinCos[i].y;
22         float y0 = - m_vSinCos[i].x*e;
23         float z0 = + m_vSinCos[i].x*f;
24 
25         float x1 = x0*h + z0*g;
26         float y1 = y0;
27         float z1 = -x0*g + z0*h;
28         
29         pVertices[i].x += x1*radius;
30         pVertices[i].y += y1*radius;
31         pVertices[i].z += z1*radius;
32     }
33 }