分形之螺线

把一条直线扭成螺旋上升，再把得到的螺旋直线当做一条直线扭成螺旋上升如此无限循环.从而生成一种分形螺线.

核心代码:

void        CFractalHelix::FractalHelix(const Vector3& vStart, const Vector3& vEnd, Vector3* pVertices)
{
    Vector3 vDir = vEnd - vStart;
    float len = D3DXVec3Length(&vDir);
    float radius = len*m_params[0];

    float xz = sqrtf(vDir.x*vDir.x + vDir.z*vDir.z);
    float angleY = atan2f(xz, vDir.y);
    float angleXZ = atan2f(vDir.x, vDir.z);

    float e = sin(angleY);
    float f = cos(angleY);

    float g = sin(angleXZ);
    float h = cos(angleXZ);

    for (int i = 0; i < CIRCLE_POINTS_COUNT; i++)
    {
        pVertices[i] = vStart + vDir*(i*1.0f/CIRCLE_POINTS_COUNT);

        float x0 = m_vSinCos[i].y;
        float y0 = - m_vSinCos[i].x*e;
        float z0 = + m_vSinCos[i].x*f;

        float x1 = x0*h + z0*g;
        float y1 = y0;
        float z1 = -x0*g + z0*h;
        
        pVertices[i].x += x1*radius;
        pVertices[i].y += y1*radius;
        pVertices[i].z += z1*radius;
    }
}

代码写得有点让人头晕,其实就是将一根线段掰弯,生成若干表示曲线的线段,然后不停迭代.不过代码还有点瑕疵,有的线段接缝过度不太顺畅.

软件截图：