[Bf-committers] possible quaternion bug

[Heikki Orsila]

I am not very familiar with quaternions, but blenlib/intern/arithb.c :
void QuatToSpher() looks odd comparing to VecRotToQuat().

QuatToSpher() has:
	qx = quat[0];
	qy = quat[1];
	qz = quat[2];
	qw = quat[3];
	cos_theta = qw;

VecRotToQuat() has:
	quat[1]= vec[0];
	quat[2]= vec[1];
	quat[3]= vec[2];
	...
	quat[0]= (float)cos( phi/2.0 );

Does blender use contradictory internal formats with quaternions?

The function QuatToSpher() has a comment that it might not work 100%.
Could the problem be fixed by just doing:

	qx = quat[1];
	qy = quat[2];
	qz = quat[3];
	qw = quat[0];

Haven't tested this. Just a suspicion.

Heikki Orsila			There has yet to be any innovation, new
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