ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Working in three dimensions (3D)
You can instantiate your own PerspectiveProjection object with the intention of modifying the projectionCenter
and fieldOfView yourself. In this case, the default values of the newly created object are the following, based on a
default stage size of 500 by 500:
fieldOfView: 55
perspectiveCenter: 250,250
focalLength: 480.24554443359375
Example: Perspective projection
Flash Player 10 and later, Adobe AIR 1.5 and later
The following example demonstrates the use of perspective projection to create 3D space. It shows how you can modify
the vanishing point and change the perspective projection of the space through the projectionCenter property. This
modification forces the recalculation of the focalLength and fieldOfView with its concomitant distortion of the 3D
space.
This example:
1 Creates a sprite named center, as a circle with cross hairs
2 Assigns the coordinates of the center sprite to the projectionCenter property of the perspectiveProjection
property of the transform property of the root
3 Adds event listeners for mouse events that call handlers that modify the projectionCenter so that it follows the
location of the center object
4 Creates four accordion-style boxes that form the walls of the perspective space
When you test this example, ProjectionDragger.swf, drag the circle around to different locations. The vanishing point
follows the circle, landing wherever you drop it. Watch the boxes that enclose the space stretch and become distorted
when you move the projection center far from the center of the stage.
To get the application files for this sample, see www.adobe.com/go/learn_programmingAS3samples_flash. The
ProjectionDragger application files are in the Samples/ProjectionDragger folder.
Last updated 6/6/2012
357