spherical coordinate 和cartesian坐标的转换， 个人认为在控制camera的时候最为有用，比如CS中的操作方式， 鼠标负责方向的改变，其恰恰就是球形坐标的改变。而camera的位置改变就是cartesian的改变，所以这两者的转换就必不可少了。
以下是基本的数学公式，非常简单。
Thus, we can convert from spherical to Cartesian coordinates by
We convert from Cartesian to spherical coordinates by
我的代码，比较烂不要见笑, 没什么注释，比较简单大家应该可以看懂:
//_horizon, _vertical是球形坐标的改变大小
void AO_Camera::moveRatate( float _horizon, float _vertical )
{
float r, s, thi, theta, x, y, z;
x = m_forwardVector.x;
y = m_forwardVector.y;
z = m_forwardVector.z;
r = D3DXVec3Length( &m_forwardVector);
s = D3DXVec3Length( &D3DXVECTOR3( x, 0.0f, z) );
thi = acos( y / r );
//限制theta的改变范围
if ( x <= 0 )
{
theta = PI - (float)asinf( z / s );
}
else
{
theta = (float)asinf( z / s );
}
thi = thi + _vertical;
if ( thi <= PRECISION )
{
thi = PRECISION;
}
else if( thi >= PI - PRECISION )
{
thi = PI - PRECISION;
}
theta = theta - _horizon;
m_forwardVector.x = r * sin( thi ) * cos( theta );
m_forwardVector.z = r * sin( thi ) * sin( theta );
m_forwardVector.y = r * cos( thi );
m_LookAt = m_EyePos + m_forwardVector;
}
作者> chiyuwang
