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Gannroids

In the breaks I have at work I downloaded and installed Adobe’s CS4 software and decided that I would make a quick little prototype game just to learn about ActionScript 3.0 and CS4.  I did what I usually do which is to make an Asteroids clone.  This time the theme would be one of my co-workers; I wanted to blow up his head, what can I say? *grin*  The collision is a little funky due to my sloppiness/laziness but I’m satisfied for the amount of time I put into it; which I would say perhaps 12 hours over a week and a half.  Most of the time was spent learning ActionScript idiosyncrasies.  Here is the result:

For some reason the transparent pixels wouldn’t save when I uploaded to WordPress, so you get square heads.

Gannroids

CS4 has some interesting features.  One can enter media objects onto the stage and bind them to a keyword and ActionScript file.  Its seems cool at first and really easy, however it only seems useful if you have one or a few instances of a class.  For the most part I just bound the stage to my game.as file and let game.as handle everything.  I created classes for Asteroids and Bullets to learn how to do class work in ActionScript and I ran into a few problems but for the most part everything was seamless.  (As seamless as it can be writing anything in a new language).

To look at some specific problems I encountered, continue reading.

Here are the problems some encountered in no specific order:

1 – Getting graphics objects to be included in the .swf.  I never really came up with a solution, my image for asteroids is externally loaded.  I’m sure there is a way to embed graphics in the .swf and call it programatically, similar to how you can bind a symbol to a keyword I’m sure you can bind an image to a keyword to access in the code.

2 – Keeping track of things in the DisplayList.  I spent a large portion of my time here trying to figure out how to cast things into the type of objects I needed them to be and figure out the correct depths of the DisplayList.  In the end I ended up just going through every object in the display list and checking its object type if I needed to modify an object that I was using.  In other programming languages I wrote my own draw functions so I would just have a Vector containing all my objects that I had created and draw that Vector.  The DisplayList is a very similar implementation however it seemed I had less control.  I probably just don’t know the ins and outs of the DisplayList class and that will come with time I’m sure.

3 – Collision detection.  I had all sorts of problems with positioning.  The default x and y properties inherent in a DisplayObject were acting strangely so I ended up adding my own properties for x and y, which in turn caused problems with display and later with the collision calculation.  If I were to go back I would make sure to use the default x and y property better.

4 – Image centering.  One can set a registration point on a symbol in CS4 and it will set the axis of rotation (center preferably)  I could not figure out how to do this programaticlly with a property so I created a Sprite container and put an image loader object inside it and offset x and y by -imageWidth/2 (thanks Nathan)  This was another thing causing collision issues, I had multiple objects using different x/y’s and then images that were rotating were offset and I would forget what was using what.  It was close enough in the end and I was too tired to track down what was wrong with it.  Next version of anything I do I will pay more attention upfront to draw/x/y coordinates.

Overall the experience was good, I feel comfortable enough with ActionScript now and delved a little into CS4.

1 comment · Written by Tyler at 2:26 pm · coding, development, games, shmupp