Comments on: Simple rotation problem http://www.lostinactionscript.com/blog/index.php/2008/10/20/simple-rotation-problem/ Lost In Actionscript Wed, 08 Sep 2010 12:01:59 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Shane McCartney http://www.lostinactionscript.com/blog/index.php/2008/10/20/simple-rotation-problem/comment-page-1/#comment-1104 Shane McCartney Mon, 20 Oct 2008 00:16:38 +0000 http://www.lostinactionscript.com/blog/?p=82#comment-1104 Sorry and thanks for spotting that Adam I shouldn't of been so lazy in assumption that the algorithm receives a normalized angle. I have updated the above to include a normalize algorithim also. Here is my equivalent <code>cA = (Math.abs(cA)>Math.PI*2) ? (cA<0) ? cA%Math.PI*2+ Math.PI*2 : cA%Math.PI*2 : cA;</code> Sorry and thanks for spotting that Adam I shouldn’t of been so lazy in assumption that the algorithm receives a normalized angle. I have updated the above to include a normalize algorithim also. Here is my equivalent
cA = (Math.abs(cA)>Math.PI*2) ? (cA<0) ? cA%Math.PI*2+ Math.PI*2 : cA%Math.PI*2 : cA;

]]> By: Adam http://www.lostinactionscript.com/blog/index.php/2008/10/20/simple-rotation-problem/comment-page-1/#comment-1102 Adam Sun, 19 Oct 2008 23:20:00 +0000 http://www.lostinactionscript.com/blog/?p=82#comment-1102 Hi Shane, Not sure if it's just a bug in your example, but if you get the blue arrow to follow the green arrow clockwise for two revolutions, you'll see the blue arrow spin back in the opposite direction. I had to tackle this same issue recently and came up with the following code. Not so efficient, but it works. <code> public static function normalizeRotation(rotation:Number):Number { rotation = rotation % 360; if (rotation 180) { diff -= 360; } else if (diff < -180){ diff += 360; } return relativeTo + diff; } </code> Hi Shane,

Not sure if it’s just a bug in your example, but if you get the blue arrow to follow the green arrow clockwise for two revolutions, you’ll see the blue arrow spin back in the opposite direction.

I had to tackle this same issue recently and came up with the following code.

Not so efficient, but it works.


public static function normalizeRotation(rotation:Number):Number {
rotation = rotation % 360;
if (rotation 180) {
diff -= 360;
} else if (diff < -180){
diff += 360;
}

return relativeTo + diff;
}

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