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  [SOLVED] How to know the rotation ?  (Read 764 times)
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Offline alaslipknot
« Posted 2013-04-21 21:41:29 »

Hello,
when i use ActionScript in Flash i use this code to make an object move forward depending on it's rotation :

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public static function moveForward (o1:Object, s:Number)
      {
         o1.x = o1.x + Math.cos(o1.rotation / 180 * Math.PI) * s;
         o1.y = o1.y + Math.sin(o1.rotation / 180 * Math.PI) * s;
      }


how can i find the rotation of an object ?

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Offline davidc

Senior Member


Medals: 5
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« Reply #1 - Posted 2013-04-22 01:31:57 »

What information about the object do you currently have? Is it an instance of your own class? Do you know anything about its velocity?

It sounds like you will need to be storing some information within these objects, such as the direction they are currently moving.
Offline vbrain
« Reply #2 - Posted 2013-04-22 02:38:49 »

How can you find the rotation of an object?

Do you have a class for that type of object which holds its variables such as position and speed? Do you have any Java code? Do you know any Java?

I know some ActionScript, and I know why you would think that an image has a rotation you can get from it, but Java doesn't work that way.
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Offline SHC
« Reply #3 - Posted 2013-04-22 09:49:20 »

Shouldn't it be

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Math.sin(-1 * o1.rotation / 180 * Math.PI)


Isn't the y-axis inverted?

Offline Roquen
« Reply #4 - Posted 2013-04-22 11:32:37 »

Coordinate frame convention dictates.
Offline matheus23

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« Reply #5 - Posted 2013-04-27 18:25:34 »

how can i find the rotation of an object ?

Usually you give the rotation to the object. You say your Zombie now walks in this direction, your player heads towards the mouse, etc.

I don't really understand what you mean by finding the rotation?

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Offline Jimmt
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« Reply #6 - Posted 2013-04-29 17:08:06 »

Maybe rotation relative to x axis? atan2(dy, dx) * 180 / pi?
Offline alaslipknot
« Reply #7 - Posted 2013-04-29 19:51:46 »

sorry guys i didn't mark this topic [solved]
it seems that i wasn't understanding a lot of thing when i write this topic  Roll Eyes
anyway,
i made an easy tutorial about rotating and moving toward direction, you can see it (and correct it)  here

thank you

"It's not at all important to get it right the first time. It's vitally important to get it right the last time."
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