# Generic Quaternion Camera Class

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Guys, I'm pulling out my hair cuase this should be easy, but I can't figure out why in the world my camera class is not working, here's the code for the rotation:
void Camera::Rotate(float angle,float x,float y,float z)
{
Quaternionf temp, quat_view, result;

temp.x = x * sin(angle/2);
temp.y = y * sin(angle/2);
temp.z = z * sin(angle/2);
temp.w = cos(angle/2);

quat_view.x = m_LookAt.X();
quat_view.y = m_LookAt.Y();
quat_view.z = m_LookAt.Z();
quat_view.w = 0;

Quaternionf preConj = temp * quat_view;
temp.Conjugate();

result = preConj * temp;

m_LookAt.X( result.x );
m_LookAt.Y( result.y );
m_LookAt.Z( result.z );
}


Here's how my game initializes the camera:
	m_Camera.Position(50.0f,600.0f,-300.0f);
m_Camera.LookAt(50.0f,0.0f,0.0f);
m_Camera.Up(0.0f,1.0f,0.0f);
m_Camera.Far(3000.0f);
m_Camera.Near(1.0f);
m_Camera.Aspect(3.14f/4.0f);
m_Camera.FOV(800.0f/600.0f);


And lastly, I'm just trying to get the rotation working, so during update I'm calling this;
m_Camera.Rotate(0.1f,0.0f,1.0f,0.0f);


It just jiggles the camera, but no real movement??? Any ideas??? Thanks in advance Jeff.

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Are you sure the quaternion multiplication and conjugation functions are implemented correctly, and that the Quaternionf.Conjugate() method alters the quaternion in place instead of returning a value?

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Is m_lookAt the target point for the camera (as the code suggests), or is it a view direction? If it's the former, then rotating it as you're doing is almost certainly not going to give you the results you're looking for.

Also, my usual mini-rant: The use of quaternions here is not only pointless, but actually serves to obfuscate what would otherwise be a fairly straightforward operation (in fact, eliminating the quaternions would be a good first step toward figuring out what the real problem is). Furthermore, the whole 'rotate the look-at point/vector' approach to camera control is equally pointless and obfuscated (IMO, at least). Whatever camera control scheme you're after (FPS, 6DOF, orbital, etc.), there is almost certainly a better way to go about it.

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