ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Working in three dimensions (3D)
(0,0,0)
D
B
A
The positive directions of the x, y, and z axes in the ActionScript 3D coordinate system.
A. + Z axis B. Origin C. +X axis D. +Y axis
Note: Be aware that Flash Player and AIR always represent 3D in layers. This means that if object A is in front of object
B on the display list, Flash Player or AIR always renders A in front of B regardless of the z-axis values of the two objects.
To resolve this conflict between the display list order and the z-axis order, use the transform.getRelativeMatrix3D()
method to save and then re-order the layers of 3D display objects. For more information, see “Using Matrix3D objects for
reordering display” on page 362.
The following ActionScript classes support the new 3D-related features:
1 The flash.display.DisplayObject class contains the z property and new rotation and scaling properties for
manipulating display objects in 3D space. The DisplayObject.local3DToGlobal() method offers a simple way
to project 3D geometry onto a 2D plane.
2 The flash.geom.Vector3D class can be used as a data structure for managing 3D points. It also supports vector
mathematics.
3 The flash.geom.Matrix3D class supports complex transformations of 3D geometry, such as rotation, scaling, and
translation.
4 The flash.geom.PerspectiveProjection class controls the parameters for mapping 3D geometry onto a 2D view.
There are two different approaches to simulating 3D images in ActionScript:
C
1 Arranging and animating planar objects in 3D space. This approach involves animating display objects using the x,
y and z properties of display objects, or setting rotation and scaling properties using the DisplayObject class. More
complex motion can be achieved using the DisplayObject.transform.matrix3D object. The
DisplayObject.transform.perspectiveProjection object customizes how the display objects are drawn in 3D
perspective. Use this approach when you want to animate 3D objects that consist primarily of planes. Examples of
this approach include 3D image galleries or 2D animation objects arranged in 3D space.
2 Generating 2D triangles from 3D geometry, and rendering those triangles with textures. To use this approach you
must first define and manage data about 3D objects and then convert that data into 2D triangles for rendering.
Bitmap textures can be mapped to these triangles, and then the triangles are drawn to a graphics object using the
Graphics.drawTriangles() method. Examples of this approach include loading 3D model data from a file and
rendering the model on the screen, or generating and drawing 3D terrain as triangle meshes.
Last updated 6/6/2012
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