' This example builds a couple of Actions, one which has
' the sphere moving slowly on a three-sided path, the other
' which has the sphere moving quickly on a four-sided path.
' It then uses a bridge transition to perform a correct
' transition between these two looped motions (which have
' different periods). 
slowPeriod = 30         ' period of the slow looping Action
fastPeriod = 12         ' period of the fast looping Action
preFade = 60            ' approx time to cycle before starting transition
crossFade = 100         ' approx desired duration of transition
posParams = "/kine.local.posx,kine.local.posy,kine.local.posz"
' Create an object for our example.
set oObj = CreatePrim( "Sphere", "MeshSurface" )
' Make an Action with it moving slowly in a wide (three-sided) loop.
BuildLoop oObj, slowPeriod, 15, false
set oSlowSource = StoreAction( , oObj & posParams, 2, "Slow", True, _
                                0, slowPeriod - 1 )
' Make an Action with it moving quickly in a tight (four-sided) loop.
BuildLoop oObj, fastPeriod, 3, true
set oFastSource = StoreAction( , oObj & posParams, 2, "Fast", True, _
                                0, fastPeriod - 1 )
' Instantiate the Actions on the mixer -- cycled,
' overlapped and ready for the Bridge Transition.
set oSlowClip = AddClip( "Scene_Root", oSlowSource, , , 1 )
set oFastClip = AddClip( "Scene_Root", oFastSource, , , _
                                round( preFade / slowPeriod ) * slowPeriod + 1 )
overlapSlowCycles = round( ( crossFade + preFade - slowPeriod ) / slowPeriod )
SetValue oSlowClip & ".actionclip.timectrl.extrapaft_type", 2
SetValue oSlowClip & ".actionclip.timectrl.extrapaft_nbcycles", overlapSlowCycles
SetValue oFastClip & ".actionclip.timectrl.extrapaft_type", 2
SetValue oFastClip & ".actionclip.timectrl.extrapaft_nbcycles", _
                                round( overlapSlowCycles * slowPeriod / fastPeriod ) + 1
' Apply the Bridge Transition, which will match the
' frequency of the periodic motions.  Compare it to
' a regular transition, where the motions tend to
' cancel each other out if they are at different frequencies.
AddBridgeTransition oSlowClip, oFastClip
' Set a suitable timeline start/end for playback of this example.
SetValue "PlayControl.In", 1
SetValue "PlayControl.Out", GetValue( oFastClip & ".actionclip.timectrl.resout" )
'==================================================
' Helper method to create the looping paths (three- or four-sided).
'==================================================
sub BuildLoop( in_oObj, in_period, in_size, in_bFourSided )
        SetPositionKey in_oObj, 0,                              -0.5 * in_size, -0.5 * in_size, 0
        if in_bFourSided then
                SetPositionKey in_oObj, in_period / 4,  0.5 * in_size, -0.5 * in_size, 0
                SetPositionKey in_oObj, in_period / 2,  0.5 * in_size, 0.5 * in_size, 0
                SetPositionKey in_oObj, 3 * in_period / 4,      -0.5 * in_size, 0.5 * in_size, 0
        else
                SetPositionKey in_oObj, in_period / 3,  0.5 * in_size, -0.5 * in_size, 0
                SetPositionKey in_oObj, 2 * in_period / 3,      0, 0.5 * in_size, 0
        end if
        SetPositionKey in_oObj, in_period,                      -0.5 * in_size, -0.5 * in_size, 0
end sub
'==================================================
' Helper method to key an object somewhere at a given frame.
'==================================================
sub SetPositionKey( in_oObj, in_frame, in_posX, in_posY, in_posZ )
        Translate in_oObj, in_posX, in_posY, in_posZ, siAbsolute, siParent, siObj, siXYZ
        SaveKey in_oObj & posParams, in_frame
end sub