Rotation

ryan · 23rd July 2002, 01:53

I was wondering if anyone could post a movement code for rotation.

UnConeD · 23rd July 2002, 10:57

Mmmm this needs to become a FAQ. Basic rotation goes like this:

x' = x*cos(a) - y*sin(a);
y' = x*sin(a) + y*cos(a);

where a is the angle in radians.

This rotates the point (x,y) around the origin to become (x',y'). To rotate around a different point, first translate the point so that the rotation center is the origin, and then translate back again.

For 3D, you can rotate around the 3 axes by using (x,y), (x,z) or (y,z) as the coordinates in the formula above.

23rd July 2002, 01:53	#1
ryan not fucked, not quite. (Forum King) Join Date: Feb 2002 Location: Tn Posts: 8,755	Rotation I was wondering if anyone could post a movement code for rotation.

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23rd July 2002, 10:57	#2
UnConeD Whacked Moderator Join Date: Jun 2001 Posts: 2,104	Mmmm this needs to become a FAQ. Basic rotation goes like this: x' = xcos(a) - ysin(a); y' = xsin(a) + ycos(a); where a is the angle in radians. This rotates the point (x,y) around the origin to become (x',y'). To rotate around a different point, first translate the point so that the rotation center is the origin, and then translate back again. For 3D, you can rotate around the 3 axes by using (x,y), (x,z) or (y,z) as the coordinates in the formula above.