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triggerCallback

Syntax

    sprite(whichQTVRSprite).triggerCallback
    triggerCallback of sprite whichQTVRSprite

Description

QuickTime VR sprite property; contains the name of the handler that runs when the user clicks a hotspot in a QuickTime VR movie. The handler is sent two arguments: the `me` parameter and the ID of the hotspot that the user clicked.

The value that the handler returns determines how the movie processes the hotspot. If the handler returns `#continue`, the QuickTime VR sprite continues to process the hotspot normally. If the handler returns `#cancel`, the default behavior for the hotspot is canceled.

Set this property to 0 to clear the callback.

The QuickTime VR sprite receives the message first.

To avoid a decrease in performance, set the `triggerCallback` property only when necessary.

This property can be tested and set.

Example

This statement sets the callback handler for a QuickTime VR sprite to the handler named `MyHotSpotCallback` when the playback head first enters the sprite span. Every time that hotspot is triggered, the `MyHotSpotCallback` handler is executed. When the playback head leaves the sprite span, the callback is canceled.

    property pMySpriteNum, spriteNum

    on beginSprite me
    	pMySpriteNum = me.spriteNum
    	sprite(pMySpriteNum).triggerCallback = #MyHotSpotCallback
    end

    on MyHotSpotCallback me, hotSpotID
    	put "Hotspot" && hotSpotID && "was just triggered"
    end

    on endSprite me
    	sprite(pMySpriteNum).triggerCallback = 0
    end