Problems with rotation and negative numbers

[ferrari24]

I am working on a game where the user navigates a MC around with the arrow keys and rotates towards the direction that the user is going. There is a problem with negative degrees for _rotation of the MC.

onClipEvent(enterFrame){
	if(_rotation<rot){
		_rotation+=15;
	}
	if(_rotation>rot){
		_rotation-=15;
	}
	trace(_rotation);
	if(Key.isDown(Key.LEFT)){
		_x-=5;
		rot=90;
	}
	if(Key.isDown(Key.RIGHT)){
		_x+=5;
		rot=-90;
	}
	if(Key.isDown(Key.UP)){
		_y-=5;
		rot=180;
	}
	if(Key.isDown(Key.DOWN)){
		_y+=5;
		rot=0;
	}
	if(Key.isDown(Key.DOWN)&&Key.isDown(Key.LEFT)){
		rot=45;
	}
	if(Key.isDown(Key.DOWN)&&Key.isDown(Key.RIGHT)){
		rot=-45;
	}
	if(Key.isDown(Key.UP)&&Key.isDown(Key.LEFT)){
		rot=135;
	}
	if(Key.isDown(Key.UP)&&Key.isDown(Key.RIGHT)){
		rot=-135;
	}
	if(_x<_width/2){
		_x=_width/2;
	}
	if(_x>640-_width/2){
		_x=640-_width/2;
	}
	if(_y<_height/2){
		_y=_height/2;
	}
	if(_y>480-_height/2){
		 _y=480-_height/2;
	}
}

When the user is pointed right and presses up the MC moves clockwise to up instead of counterclockwise, and visa-versa to go right from up.

[Josiah]

I think this is because flash's Y axis is inverted, meaning opposite than what we were taught in Math class. In math, when you go up, the Y axis increases, in flash when you go up, the Y value decreases.

You may be able to fix this by multiplying your final rotation by -1 ?? Just a thought.

Hope this helps....

[Josiah]

or just had another thought...instead of using the negative values, use the positive values...so instead of -90 you would use 270...that might do it

[ferrari24]

Well it reads the _rotation thing, which if >180° is negative, and multiplying that by -1 doesn't do anything. I guess I should try using a variable for the rotation and having a conversion to have it negative when it should be or something.