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DeadmanDines
Best Article Writer
Registered
27/04/2006
Points
4758
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28th September, 2006 at 18:27:56 -
I'm having some trouble getting an 'angle between two points' expression to work.
The expression I'm using right now is:
ATan((Y( "BOUNCE" )+0.0-Y( "Active" )+0.0)/(X( "BOUNCE" )+0.0-X( "Active" )+0.0))
This is being done in MMF2, demo version (hence why I can't just use an extension to do it for me).
For some reason, it works from 0 to 90 degrees, and then starts going into minus figures... and then back into positives again. And then back into negatives.
The result is that directly up left from the object is 45 degrees...
...But directly DOWN LEFT is also 45 degrees.
The help file says that ATAN uses degrees, just like Sin and Cos, but is there a problem with ATan? Am I just doing it wrong?
If ATan is retarded, can I use an alternative expression to get the angle?
191 / 9999 * 7 + 191 * 7
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Ski
TDC is my stress ball
Registered
13/03/2005
Points
10130
         
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28th September, 2006 at 18:47:44 -
Even I cant help you on that one 
n/a
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Joe.H
Evil Faker
Registered
19/08/2002
Points
3305
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28th September, 2006 at 20:32:52 -
No, it's right. It just means the angle falls in a different quadrant.
If you get the angle as as - number, just add 180 to the angle and you should get another value which will give the same answer. However, if may not neccesarily give you the angle you want. The positive value of the negative value will also return the same answer. There are several different answers you could get for the correct angle though, MMF just returns one of them. If it's < 0, just keep adding 180 until you get 0 <= angle <= 360, and try and make a system which chooses the correct one from a possible value. (usually it would be the first one it comes to that's 0 < a < 360)
Maybe. I'm tired atm so my maths brain isn't working ^^
My signature is never too big!!!
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DeadmanDines
Best Article Writer
Registered
27/04/2006
Points
4758
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29th September, 2006 at 08:11:59 -
...so how exactly do I find the angle between two points?
191 / 9999 * 7 + 191 * 7
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AndyUK
Mascot Maniac
Registered
01/08/2002
Points
14586
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29th September, 2006 at 08:22:49 -
I think podunkian made an extension that does that for you.
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..:.Phox.:..
Registered
18/02/2005
Points
646
   
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29th September, 2006 at 12:50:14 -
yep
Profile edited as it messed the layout of the site up.
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markno2
Registered
06/06/2006
Points
865
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29th September, 2006 at 13:50:30 -
.....You lost me at hello.
Discarded pizza boxes are an indispensable source of cheese.
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Werbad
Registered
18/09/2002
Points
235
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3rd October, 2006 at 06:58:04 -
If i remember correctly, ATan will only return a number that is -90 -> 90, so you'll need to do extra chacks to find the correct angle
n/a
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Alex Wells
Registered
23/06/2005
Points
28
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3rd October, 2006 at 13:50:19 -
Yeah... dude use the advanced direction calculator 
Battalion/Eden Online--
In internal testing
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Reno
Registered
11/01/2005
Points
906
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3rd October, 2006 at 16:16:44 -
wow I hesitated when clicking this link, but yet I seemed to have eventually clicked this link :|
I hate trig. 
Reborn Again
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axel
Crazy?
Registered
05/02/2005
Points
4766
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3rd October, 2006 at 16:56:48 -
I'm too stupid for trig, but I can still make 360 deg movement engines, yay!
n/a
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