[FONT=Arial]Hello to everyone. I love Kirupa![/FONT]
[FONT=Arial]I am wrapping my brain around OOP in AS2 and I need some advice. I am making two posts on two different subjects.[/FONT]
[FONT=Arial]My question here is: when should I use local instance variables, and when should I attach new properties to the instance object? (Feel free to correct my terminology.)[/FONT]
[FONT=Arial]Let’s say I have a class for a scrolling background, which scrolls when I mouse over its edge. I want to put these values somewhere:[/FONT]
[FONT=Arial]1) How wide is the border in which a mouseOver makes it scroll? This is basically a semi-constant—I set it up once and keep it the same, unless the user changes it in an options menu to make the border wider or narrower. Call this “scrollBorderWidth”.[/FONT]
[FONT=Arial]2) How fast is the background scrolling now? I want to track this so I can smoothly change the scroll speed over several frames. This is often changed. Call this “scrollSpeed”.[/FONT]
[FONT=Arial]It seems I have two ways I can store and access these values and darned if I know which is better practice.[/FONT]
[FONT=Arial]***METHOD A: [/FONT]
[FONT=Arial]Make them local variables in the class, so the scrolling background instance has them as local vars. I set them up thusly:[/FONT]
[FONT=Arial]class ScrollingBkgnd {[/FONT]
[FONT=Arial]var scrollBorderWidth:Number = 50;[/FONT]
[FONT=Arial]var scrollSpeed:Number = 0;[/FONT]
[FONT=Arial]//constructor etc[/FONT]
[FONT=Arial]function foobar(Void) {[/FONT]
[FONT=Arial]if(_xmouse < scrollBorderWidth) doSomething;[/FONT]
[FONT=Arial]scrollSpeed++;[/FONT]
[FONT=Arial]}[/FONT]
[FONT=Arial]}[/FONT]
[FONT=Arial]***METHOD B:[/FONT]
[FONT=Arial]Make them properties of the instance (and the class dynamic), so the scrolling background instance object has them as new object properties. I set them up thusly:[/FONT]
[FONT=Arial]dynamic class ScrollingBkgnd {[/FONT]
[FONT=Arial]//constructor etc[/FONT]
[FONT=Arial]function init(Void) {[/FONT]
[FONT=Arial]this.scrollBorderWidth = 50;[/FONT]
[FONT=Arial]this.scrollSpeed = 0;[/FONT]
[FONT=Arial]}[/FONT]
[FONT=Arial]function foobar(Void) {[/FONT]
[FONT=Arial]if(_xmouse < this.scrollBorderWidth) doSomething;[/FONT]
[FONT=Arial]this.scrollSpeed++;[/FONT]
[FONT=Arial]}[/FONT]
[FONT=Arial]}[/FONT]
[FONT=Arial]***QUESTION:[/FONT]
[FONT=Arial]Which method should I use, A or B? My main priorities are, in order:[/FONT]
[FONT=Arial]1) Make code that can scale up to be part of a rather complex application.[/FONT]
[FONT=Arial]2) Make code which will be easily reusable in other projects.[/FONT]
[FONT=Arial]3) Make code which is comprehensible to other (real) coders (me being a fake one).[/FONT]
[FONT=Arial]???[/FONT]
[FONT=Arial]Thanks very much for any advice you can give to someone who wants to do good OOP but is lacking much formal training.[/FONT]
