Original Post
I've run into some trouble with my Quaternion based camera movement. At the moment I am getting yaw and pitch values from the mouse, and then converting them to quaternions and then to a matrix. The problem is occurring when the yaw gets close to 180 degrees, any change in the pitch causes strange warping instead of rotation I suspect It has something to do with either my quaternion concat code or my quaternion to matrix code. Unfortunately my knowledge of this math is quite limited so I was wondering if anyone sees anything overtly wrong with this code, or has any other ideas about what might be wrong.
Quaternion rot = Quaternion(Vector3f(1.0f, 0.0f, 0.0f), pitch) * Quaternion(Vector3f(0.0f, 1.0f, 0.0f), yaw);
Matrix.h
class Matrix4x4 {
float m_[16];
...
void setRotation( const Quaternion& quat ) {
float xx = 2 * quat.x * quat.x;
float xy = 2 * quat.x * quat.y;
float xz = 2 * quat.x * quat.z;
float xw = 2 * quat.x * quat.w;
float yy = 2 * quat.y * quat.y;
float yz = 2 * quat.y * quat.z;
float yw = 2 * quat.y * quat.w;
float zz = 2 * quat.z * quat.z;
float zw = 2 * quat.z * quat.w;
m_[0] = 1 - (yy + zz); m_[4] = (xy + zw); m_[ 8] = (xz - yw);
m_[1] = (xy - zw); m_[5] = 1 - (xx + zz); m_[ 9] = (xy + xw);
m_[2] = (xz + yw); m_[6] = (yz - xw); m_[10] = 1 - (xx + yy);
}
}
class Quaternion {
float w, x, y, z;
...
inline Quaternion operator*(const Quaternion& q) const {
Quaternion ret(
(w*q.w) - (x*q.x) - (y*q.y) - (z*q.z),
(w*q.x) + (x*q.w) + (y*q.z) - (z*q.y),
(w*q.y) + (y*q.w) + (z*q.x) - (x*q.z),
(w*q.z) + (z*q.w) + (x*q.y) - (y*q.x)
);
return ret;
}
}
