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jPCT-AE - a 3d engine for Android => Support => Topic started by: guillaume on December 12, 2011, 01:27:59 am

Title: newbie question, how to rotate around a designated axis in jPct ?
Post by: guillaume on December 12, 2011, 01:27:59 am

said I want to rotate a rectangle around a axis which is parallel to XAxis, how can I do this in jPCT,
can someone show me some code ? I am new to opengl and jPCT programming. thanks.

Title: Re: newbie question, how to rotate around a designated axis in jPct ?
Post by: EgonOlsen on December 12, 2011, 07:43:22 am

Like so: http://www.jpct.net/jpct-ae/doc/com/threed/jpct/Object3D.html#rotateAxis(com.threed.jpct.SimpleVector, float) (http://www.jpct.net/jpct-ae/doc/com/threed/jpct/Object3D.html#rotateAxis(com.threed.jpct.SimpleVector, float))

Title: Re: newbie question, how to rotate around a designated axis in jPct ?
Post by: guillaume on December 12, 2011, 11:15:25 am

http://www.jpct.net/jpct-ae/doc/com/threed/jpct/Object3D.html#rotateAxis(com.threed.jpct.SimpleVector, float)
if I use this api,  how should I represent a axis  (for example  x=4)  in vector form ? thanks.

Title: Re: newbie question, how to rotate around a designated axis in jPct ?
Post by: EgonOlsen on December 12, 2011, 12:34:21 pm

x=4 is no axis. I'm not sure what you are after...maybe setRotationPivot() is more what you want?

Title: Re: newbie question, how to rotate around a designated axis in jPct ?
Post by: guillaume on December 12, 2011, 12:37:45 pm

Quote from: EgonOlsen on December 12, 2011, 12:34:21 pm

x=4 is no axis. I'm not sure what you are after...maybe setRotationPivot() is more what you want?

oh, I mean a line parallel to Y axis and pass through  point (4,0,0). how can I rotate around this ?

Title: Re: newbie question, how to rotate around a designated axis in jPct ?
Post by: EgonOlsen on December 12, 2011, 12:42:50 pm

By offsetting the rotation pivot. Try object.setRotationPivot(4,0,0) and do a rotateY() afterwards.