Physics Joints - Learn SpriteBuilder for iOS Game Development - page 300

This thought experiment helped to isolate the collision participants whose categories and
masks need to be edited: player, trigger, border, and obstacle. You'll later add the spring to
the mixture as well.
Coincidentally, you'll be naming the corresponding collision categories as follows:
player , trigger , border, and obstacle . The required collision categories and
masks are outlined in Table 9-1 .
Table 9-1 . Collision categories and masks needed to prevent chains
and ropes from colliding with triggers and borders while preserving
existing collision behavior
Editing Collision Categories and Masks
Let's start the editing process with the player. Open Player.ccb , and select the root node
( CCSprite ). On the Item Physics tab, enter player in the Categories field, and enter the fol-
lowing in the Masks field: trigger, border, obstacle .
In order to create multiple independent category and mask labels, you have to separate
them with a comma. If you separate the tags with any other character—space, for in-
stance—you'll get a single combined label. You don't want a single “trigger border
obstacle” label like you see on the left side of Figure 9-15 ; you want three separate labels
like on the right side of Figure 9-15 .
Figure 9-15 . Labels you type into the Categories and Masks fields must be comma-separated to create indi-
vidual labels (like those shown on the right side)
The player is now set up to collide with triggers, borders, and obstacles.