FLASH: Move an object in a circle without tweening

[John Croteau]

Hi all,


I just answered a question on how to use Trig functions (on the MM

newsgroup) and thought you might want to see the code for moving an

object in a circle using our Plug and play Trig function. You do NOT

need to be a programmer to use this.

You do need the latest version of the Trig Plug and Play though.

http://www.FlashBible.com/Members/ActionScript/PlugNPlay/Trig.htm


If you have seen our new demo in the Preloader Plug and Play you will

see the use of Sine and Cosine to move the arrows at an angle using

properties and not Tweens. Don't forget to click on the Sun.

http://www.FlashBible.com/Members/ActionScript/PlugNPlay/Preloader.htm


I have 2 Tutorials coming out soon showing both moving an object at an

angle and moving one in a circular motion. I have included an advance

copy of the script below for moving a movie clip symbol in a circle. 

The formula we use for a point on a circle are

x = Xcenter + (Radius * Sine(angle) )

y = Ycenter + (Radius * Cosine(angle) )

   * is used in Flash for multiplication


The script below will rotate a movie clip MC in a circle.

Xpos and Ypos are the x and y offsets.

Answer is the result (sine or cosine) returned from the Trig Call

functions.

Speed is the Angle difference checked (5 would start do 5, 10, 15, 20

etc.)

R is radius of circle path.


You need to set 4 variables before the action loop such as:

Set Variable: "Xpos" = 200

Set Variable: "Ypos" = 200

Set Variable: "R" = "100"

Set Variable: "Speed" = "5"


You need 2 frames for the action - the first below and one following it

that loops back to the first.


Set Variable: "Angle" = Angle + Speed

If (Angle > 360 )

      Set Variable: "Angle" = Angle - 360

End If

Call ("Trig:Sin")

Set Property ("/mc", X Position) = Xpos + (R * Answer)

Call ("Trig:Cos")

Set Property ("/mc", Y Position) = Ypos - (R * Answer)


-- 

Coming Soon    Flash 4 Web Animation F/X and Design

  http://www.amazon.com/exec/obidos/ASIN/1576105555/flashcentral

-----------                               -----------------------

John Croteau

croteauerols [dot] com (mailto:croteauerols [dot] com)

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