Hello everyone. Basically, right now I am writing a camera, but I will need the code later to rotate all of my objects. So, my problem is that I wish to rotate my objects arbitrarily, without any constraints (such as if I drag the mouse up, I wish to have my camera rotate more and more until I can make a 360). Right now, it doesn't seem to work. Ok, what I am doing now is this: - Rotation around the Y axis (left and right) I rotate a quaternion qA around the (0,1,0) axis, by given degree, and store it. - Rotation around the X axis (up and down) (quaternion qB) I calculate the view vector (camView - camPos), normalize that, then I take a cross product of the view vector with my up vector, and use that as my axis to rotate around the X axis. That works, but when I look all the way down my view flips to go to the reverse, instead of continuing to rotate (I hope you know what i mean). Yes and I want to keep rotation so that if I keep dragging my mouse down eventually the world would be upside down. - Rotation around the Z axis (tilting) (quaternion qC) I didn't even get that to work :( Stupid stupid stupid. At the end, I multiply qA * qB (i ignore qC because it just doesn't work as i want) and then i do something that looks like this

CVector3 CQuaternion::Rotate (const CVector3& v) const
{
	CQuaternion vec2 = (*this) * CQuaternion(0, v.x, v.y, v.z) * CQuaternion (r, -x, -y, -z);

	return CVector3 (vec2.x, vec2.y, vec2.z);
}

(I forgot where I ripped that from. Code's not mine). the passed parameter is actually the viewVector calculated earlier. So, I get the result from that function taking the view vector, I set the camView to camPos + result, and voila! It works like a normal camera, but not what I want. If anyone could please give me a heads up on what I should do to make my unconstrained camera, I'd be highly grateful. Btw, I really don't want to use Matricies, or anything else (like OpenGL axis rotations). Thanks. - Tima

Hmm. I see, I already have an implementation of Euler to Quat, and it works the same way. Still not going the way I want it to though.

Could you please elaborate on the concept of a "local" vector? would that be the vector perpendicular to my current view vector? I think I see where you are going with this... at least it is sort of making sense in my head.

What about rotation around the Z axis? Any ideas how I would go about doing that?

Thanks guys, you're being very helpful.

- Tima

hmm, I see.

I have a couple of questions though.

First, would the initial value of camera.up be 0,1,0 (considering I use Y axis as up)?

Second, what is the difference between the target and camera.direction? Sorry, this should be obvious but I just don't see it, and then as addition how should target be updated in relation to the general camera set up?

I think thats all for now.
Thanks!


Regards,
- Tima

EDIT: nevermind, it all works fine!

Thank you very much for all of your help, it was a pleasure having to recieve help from you guys.

Here's the working code:

		//==========================		// Get all the prerequisites		//==========================		vector3 direction = new vector3(view.x - position.x,										view.y - position.y,										view.z - position.z);		direction.Normalize();		right = direction.CrossProduct(up).GetNormalized();		up = right.CrossProduct(direction);		//=====================		// Do all the rotations		//=====================		rotation.SetRotation(-x, right);		rotation = rotation.Mul(new quaternion(y, up));		direction = rotation.Rotate(direction);		view.x = position.x + direction.x;		view.y = position.y + direction.y;		view.z = position.z + direction.z;

Thank you very very much :)
- Tima