I am having trouble converting eulers into quaternions for use in .b3d files. I am using the code from Mark Sibly's MS3D .b3d exporter, but it does not produce correct results:
Procedure EulerAsQuat(pitch.f,yaw.f,roll.f)
sp.f=Sine(pitch/2.0)
cp.f=Cosine(pitch/2.0)
sy.f=Sine(yaw/2.0)
cy.f=Cosine(yaw/2.0)
sr.f=Sine(roll/2.0)
cr.f=Cosine(roll/2.0)
vectorw.f=cr*cp*cy+sr*sp*sy
vectorx.f=sr*cp*cy-cr*sp*sy
vectory.f=cr*sp*cy+sr*cp*sy
vectorz.f=-(cr*cp*sy-sr*sp*cy)
EndProcedure
From what I can figure out,bearing in mind it is late ^^ try
vectorw.f =cy*cp*cr - sy*sp*sr
vectorx.f =cy*cp*sr + sy*sp*cr
vectory.f =sy*cp*cr + cy*sp*sr
vectorz.f =cy*sp*cr - sy*cp*sr
That did not work.
I am checking the euler I put into the function, and the euler Blitz3D calculates is NOT the same.
My exporter says 0.0,90.0,-90.0 --> Blitz3D says 0.0,-90.0,90.0
When I rotate the object in Blitz3D to 0.0,90.0,-90.0, the same angles my editor says, it has the exact same orientation. So the problem is definitely the translation of the euler to the quaternion and back.
Halo, if it's any help an entitys current Quat is at:
w#= peekmemfloat(ent+48)
x#= peekmemfloat(ent+52)
y#= peekmemfloat(ent+56)
z#= peekmemfloat(ent+60)
I've not got a working function for euler>quat as when certain values exceed +/- 90 degrees, the quat is completely negative.
Thanks for that.
I wrote a program that shows that the EulerAsQuat function in the MS3D exporter does not convert a Euler to the same Quaternion Blitz3D does:
I uploaded the source code and required userlib:
http://www.leadwerks.com/post/quatprob.zip I got it working, using this code. This is THE RIGHT WAY to convert a euler into a Blitz3D quaternion!:
Procedure EulerAsQuat(pitch.f,yaw.f,roll.f)
sp.f=Sine(yaw/2)
cp.f=Cosine(yaw/2)
sy.f=Sine(roll/2)
cy.f=Cosine(roll/2)
sr.f=Sine(pitch/2)
cr.f=Cosine(pitch/2)
vectorw.f=(cr*cp*cy-sr*sp*sy)
vectorx.f=-(sr*cp*cy-cr*sp*sy)
vectory.f=(cr*sp*cy+sr*cp*sy)
vectorz.f=-(sr*sp*cy+cr*cp*sy)
EndProcedure
Great work!
After half an hour I could see that a Blitz quaternions are unique and different to the way the rest of the planet does them lol! -.-
[edit] think its a typo in the blitz3d sourcecode? or does Mark just love to be different ;)
Still, now that you can convert a euler to a Blitz3D quaternion, you can use it with the geometry code Mark posted.