ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Working with bitmaps
import flash.display.Bitmap;
import flash.display.BitmapData;
var myBitmapDataObject:BitmapData = new BitmapData(1000, 1000, false, 0x00FF0000);
var seed:Number = Math.floor(Math.random() * 100);
var channels:uint = BitmapDataChannel.GREEN | BitmapDataChannel.BLUE;
myBitmapDataObject.perlinNoise(100, 80, 6, seed, false, true, channels, false, null);
var myBitmap:Bitmap = new Bitmap(myBitmapDataObject);
myBitmap.x = -750;
myBitmap.y = -750;
addChild(myBitmap);
addEventListener(Event.ENTER_FRAME, scrollBitmap);
function scrollBitmap(event:Event):void
{
myBitmapDataObject.scroll(1, 1);
}
Taking advantage of mipmapping
Flash Player 9 and later, Adobe AIR 1.0 and later
MIP maps (also known as mipmaps), are bitmaps grouped together and associated with a texture to increase runtime
rendering quality and performance. Each bitmap image in the MIP map is a version of the main bitmap image, but at
a reduced level of detail from the main image.
For example, you can have a MIP map that includes at the highest quality a main image at 64 × 64 pixels. Lower quality
images in the MIP map would be 32 × 32, 16 × 16, 8 × 8, 4 × 4, 2 × 2, and 1 × 1 pixels.
Texture streaming is the ability to load the lowest quality bitmap first, and then to progressively display higher quality
bitmaps as the bitmaps are loaded. Because lower quality bitmaps are small, they load faster than the main image.
Therefore, application users can view image in an application before the main, high quality bitmap loads.
Flash Player 9.115.0 and later versions and AIR implement this technology (the process is called mipmapping), by
creating optimized versions of varying scale of each bitmap (starting at 50%).
Flash Player 11.3 and AIR 3.3 support texture streaming through the streamingLevels parameter of the
Context3D.createCubeTexture() and Context3D.createTexture() methods.
MIP maps are created for the following types of bitmaps:
a bitmap (JPEG, GIF, or PNG files) displayed using the ActionScript 3.0 Loader class
a bitmap in the library of a Flash Professional document
a BitmapData object
a bitmap displayed using the ActionScript 2.0 loadMovie() function
MIP maps are not applied to filtered objects or bitmap-cached movie clips. However, MIP maps are applied if you have
bitmap transformations within a filtered display object, even if the bitmap is within masked content.
Last updated 6/6/2012
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