Adobe Director Basics

ADOBE DIRECTOR BASICS
3D: Controlling action
property pPuck -- model("Puck")
property pAcceleration -- -0.001
property plPositions -- [: , ...]
property pThrowTime -- milliseconds when puck was released
property pThrowSpot -- world position where puck was released
property pSpeed -- speed of puck when it was released
property pDirection -- direction of travel of puck on release
property pTimeToStop -- milliseconds until puck stops moving
on mouseDown(me)
pPuck = member("3D").model("Puck")
pAcceleration = -0.001
plPositions = [:]
plPositions.sort() -- enables list.findPosNear()
(the actorList).append(me)
end mouseDown
on stepFrame(me)
-- ... other code to set the position of the puck
plPositions.addProp(the milliseconds, pPuck.worldPosition)
end stepFrame
When you release the mouse button, the mThrow() handler is called. This works out where the puck was about 200
milliseconds before it was released, and where it was on the frame immediately before it was released. Below is a
simplified version of the code.
vCount = plPositions.count()
vLast = the milliseconds - 200 -- approximate time
vIndex = plPositions.findPosNear(vLast)
pThrowTime = plPositions.getPropAt(vCount)
vLast = plPositions.getPropAt(vIndex) -- recorded time
vElapsed = pThrowTime - vLast
vThen = plPositions[vIndex]
pThrowSpot = plPositions.getLast()
The variable vThen now contains the puck's position about 200 milliseconds ago, pThrowSpot contains the position
where it was on the last frame, and vElapsed contains the time between these two positions. Subtracting one position
from the other gives the displacement between the two positions.
The mThrow() handler calculates the speed and direction of the movement in two separate property variables, and also
how long it will take the puck to come to a halt due to the effect of friction.
pDirection = pThrowSpot - vThen
pSpeed = pDirection.magnitude / vElapsed
pDirection.normalize() -- unit vector
pTimeToStop = -pSpeed / pAcceleration
Calculating the current position of the puck
After you release the puck, on every frame, the mSlide() handler calculates how much time has elapsed since the puck
was released. It uses that information to determine where the puck is at the current point in time. Here is a simplified
version of the handler. It incorporates the getDistance() handler from the Linear Motion script:
Last updated 8/26/2011
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