ActionScript 3.0 Bitmaps, Clones and ColorTransforms

Less is More Ever since I started working with mobile devices with Flash and ActionScript 3.0, I’ve been looking for faster ways to move my objects through those little windows on iPhones, Androids and Blackberries. Lag time is huge and the action looks geriatric. I’ve seen some interesting things done with the bitmapped classes, and in previous posts we’ve discussed what may be helpful. However, since I haven’t used them extensively (or fully), I thought it’d be a good idea to walkthrough my thinking on the topic. For a while now I’ve been working on a a Samurai action game, and while I’ve been making progress, I keep looking for speed tweaks. In general my thoughts regarding bitmapped graphics and Bitmap classes can be summed up in Figure 1. If I create a single Bitmap object using the BitmapData objects (or convert graphic files into BitmapData elements) and then clone the object, I should be able to save processing time.

Figure 1: Cloned and Colored

Of course, I have to assume a good deal. First, I assume that processing a single instance of an object and cloning it is more efficient than creating multiple instances of the same object. I got the idea from how Flash originally used symbols over the Internet. You create one symbol and then re-used it. My idea is pretty much the same. Create once; clone many. Second, in order for an object to look like more than a single object, I want to change something about the cloned object. With my simple samurai fighter, I can change its color because it is a Bitmap object. So, first we’ll look at how to create a bitmapped object from scratch using both the Bitmap and BitmapData objects. Making Bitmapped Objects from Code I like drawing bitmapped objects or using digital photography. However, in order to best understand what’s going on, let’s start from scratch with BitmapData objects. Figure 2 shows the fundamentals of creating a bitmapped data object:

Figure 2: Implementing BitmapData Object

The ActionScript 3.0 BitmapData object contains a 32-bit integer made up of four 8-bit values (0-255). The first parameter expects a width, the second height—this is the Bitmap shape; a rectangular data matrix. The third parameter is the objects transparency, which has a default value of true (it is transparent). By setting the transparency argument to false, you make the object opaque. The 32-bit integer is the final parameter with the first two hexadecimal values being the alpha value with the final six values expressing an RGB color. The following class provides a basic example: [...]
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