Who came up with the idea of an inverted Y axis?

(John Andersson) #1

What I wonder is why adding to an entity’s Y value makes it go downward, when it should go upward?

(Martí Angelats i Ribera) #2

This is a basic question about flash. Basically the coordenade system have origin (the point (0,0)) at the top left corner of the stage. So basically the vector representing the y is going down so increasing the y value makes the entity go downwards.

To make the enetity go upwards you simply have to decrease the value of y.

PD: Yes this coordinate system have the y inverted if you compare it to the most common system. But in math it’s known that there are an infinite amount of systems and for screens this is a common one.

(John Andersson) #3

It’s just interesting, because several times I’ve been extremely confused to what’s going on.

And don’t let me get started on hitboxes and their offsets!

(Mike Evmm) #4

hah.

(Darrin) #5

Seeing them makes all the difference. So in console mode you can hit F1 to show the boxes

FP.console.enable();

or use:

		override public function render():void
{
	super.render();			
	var o:Array = new Array();
	getAll(o);
	for each (var e:Entity in o)
	{
		Draw.hitbox(e, true, 0xFF0000, 1);
	}
}
(Willard Torres) #6

This is the standard for a lot of things screen related. I think it stems from how televisions used to draw the images: left to right, top to bottom. It starts at the upper left corner.