Ah, rotation problem
June 30, 2000 09:42 PM
Since nobody ever answers these, I''ll try again. I have two points. I want to know the rotation around the y & z axes which would be applied to a line from point 1 to pass through point two. My code is as follows:
rotation[Z] = atanf( ( p2[Y] - p1[Y] )/( p2[X] - p1[X] ) );
rotation[Y] = atanf( ( p2[Z] - p1[Z] )/( p2[X] - p1[X] ) );
Is that right?
122
July 01, 2000 12:30 AM
Subtracting the source position from the target position will give you a directed vector pointing from the source to the target (which may need to be normalized).
I.e., in pseudocode terms, you would do this:
Edited by - revolver on July 1, 2000 1:31:12 AM
I.e., in pseudocode terms, you would do this:
vector3 soure, target, dir;dir = target - source; //basic vector subtractiondir.normalize(); Edited by - revolver on July 1, 2000 1:31:12 AM
Creativity is a bloody nuisance and an evil curse that will see to it that you die from stress and alcohol abuse at a very early age, that you piss off all your friends, break appointments, show up late, and have this strange bohemian urge (you know that decadent laid-back pimp-style way of life). The truly creative people I know all live lousy lives, never have time to see you, don't take care of themselves properly, have weird tastes in women and behave badly. They don't wash and they eat disgusting stuff, they are mentally unstable and are absolutely brilliant. (k10k)
July 01, 2000 10:20 AM
I know all about vectors, I am essentially finding the vector in my code already, what I want to do is rotate an object so it matches the vector. I want to rotate the object around the y & x axes, so is my code right or does someone know what the correct way of doing this is?
Morgan
Edited by - Morgan on July 1, 2000 11:21:28 AM
Morgan
Edited by - Morgan on July 1, 2000 11:21:28 AM
122
July 02, 2000 02:27 PM
Hi Morgan
ok i think your code isn''t totaly false but try this:
#define pi 3.141592654
rotation[Z] = ( atanf( ( p2[Y] - p1[Y] )/( p2[X] - p1[X] ) ) ) / 2 / pi * 360 ;
rotation[Y] = ( atanf( ( p2[Z] - p1[Z] )/( p2[X] - p1[X] ) ) ) / 2 / pi * 360 ;
i think it works so
cose these sin cos and tan functions uses rad where 360 degree are 2 * pi. That was my problem but now it works. Don''t now if i''m right but i make it the other way:
(sin((rotation[y])*2*pi/360)); and this works 100% but i don''t now what it''s in your case. Think about it and try. Good luck
)
cu
Shadow
ok i think your code isn''t totaly false but try this:
#define pi 3.141592654
rotation[Z] = ( atanf( ( p2[Y] - p1[Y] )/( p2[X] - p1[X] ) ) ) / 2 / pi * 360 ;
rotation[Y] = ( atanf( ( p2[Z] - p1[Z] )/( p2[X] - p1[X] ) ) ) / 2 / pi * 360 ;
i think it works so
cose these sin cos and tan functions uses rad where 360 degree are 2 * pi. That was my problem but now it works. Don''t now if i''m right but i make it the other way:
(sin((rotation[y])*2*pi/360)); and this works 100% but i don''t now what it''s in your case. Think about it and try. Good luck
)cu
Shadow
July 02, 2000 07:45 PM
Oh, yeah, that''s actually already implemented in my code using a #define macro, but I forgot to include it. But, using arctan for both will provide the right results?
Morgan
Morgan
122
July 03, 2000 12:16 AM
hi
i thougt the a in atanf stands for cotangens, cose i dont know about this a but if it stands for radiant then you must write:
rotation[Z] = atanf( ( p2[X] - p1[X] )/( p2[Y] - p1[Y] ) ) ;
rotation[Y] = atanf( ( p2[X] - p1[X] )/( p2[Z] - p1[Z] ) ) ;
or not??
cu
Shadow
i thougt the a in atanf stands for cotangens, cose i dont know about this a
but if it stands for radiant then you must write:rotation[Z] = atanf( ( p2[X] - p1[X] )/( p2[Y] - p1[Y] ) ) ;
rotation[Y] = atanf( ( p2[X] - p1[X] )/( p2[Z] - p1[Z] ) ) ;
or not??
cu
Shadow
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