Timelines & Triggers - Learn SpriteBuilder for iOS Game Development - page 151

On the Item Physics tab for the color node, check Enable physics , change the
type to Static , and as the Collision type enter trigger . This will allow you to
handle collisions with triggers separately. Categories and Masks can be left
empty—currently, there aren't any other dynamic objects that might activate triggers be-
sides the player.
On the Item Code Connections tab for the color node, enter Trigger as the Cus-
tom class name. This will create an instance of the (soon to be added) Trigger class
for every TriggerOnce.ccb added to the level.
Since this particular trigger should trigger only once, switch to the Item Properties
tab once more. At the bottom, click the Edit Custom Properties button and add a
custom property named triggerCount of type Int with value 1. This will make the trig-
ger activate only once before removing itself. If you omit adding this property or set it to
0, it will create a Trigger instance that triggers every time the player enters it. Values
greater than 1 will make the trigger activate the given number of times before removing it-
self from the level.
Tip Feel free to add another trigger CCB in the same way, name it Trigger-
Forever.ccb , and omit the triggerCount parameter or set its value to 0.
I'm sure you will find a use for a repeatedly activatable trigger area eventually.
Note that it's also possible to create triggers with polygon shapes as opposed to purely
rectangular shapes. However, a polygon shape will not be reflected visually in
SpriteBuilder because the color node fills a rectangular area. You would have to use a
sprite node with a corresponding trigger image if you wanted to visually display a poly-
gon trigger area in SpriteBuilder.
On the other hand, you can almost always model more complex trigger areas with mul-
tiple rectangular triggers. Trigger collision areas also rarely need to be very precise either.
So it's best to avoid using polygon-shaped triggers altogether and instead combine mul-
tiple rectangular trigger areas.
Adding Triggers to the Level
Before you add any triggers to Level1.ccb , you should first drag another plain Node
from the Node Library View onto the CCPhysicsNode in the Level1.ccb