Adobe Director Basics

ADOBE DIRECTOR BASICS
3D: Controlling action
Collision callbacks contact reports
Each time there is a collision between either Ball and the Room, or between the two Balls, the FilterCollision()
handler will be called. It will receive a linear list of ContactReport objects. The Physics member is initialized to use five
substeps, and there are two dynamic rigidBody objects. This means that up to ten ContactReports can be generated
per frame.
To visualize what a ContactReport looks like, launch the BallRoom.dir movie, then execute the following command in
the Message window to hijack the callback events:
member("Physics").registerCollisionCallback(#TestCallback)
Now, click on the 3D sprite. You can see the following output printed into the Message window:
-- [(Contact Report), (Contact Report), (Contact Report)]
-- (Contact Report)
-- "
objectA: rigidBody("room")
objectB: rigidBody("ball2")
contactPoints: [[vector( -3.8575, -28.6366, 129.8082 )]]
contactNormals: [vector( 0.0000, -1.0000, 0.0000 )]"
Then the movie will halt to prevent spamming your Message window with endless reports.
You can find the #TestCallback() handler in the Test Callback movie script.
Using a test handler to inspect the data sent to a collision callback
Notice that the objectA and objectB values are listed in the order in which the rigidBody objects were created.
RigidBody("room") was created before rigidBody("ball2"), so it appears first in the
physicsMember.getRigidBodies() list, and is given top billing in the ContactReport.
The contactPoints and contactNormals values are both lists. In the illustration above, they both contain only one
vector each. This is because the ball in question is just in contact with the base of rigidBody("room"). If the ball were
also in contact with a wall, it would be touching rigidBody("room") in two places, so both lists contain two vectors.
In the case shown above, the contactNormal value is vector(0.0, -1.0, 0.0). This vector points downwards. It
indicates that objectA touches objectB at a point where the normal to the surface of objectB is facing downwards.
Last updated 8/26/2011
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