version 1 by John Clemens
- Example: * Exclusion - Excluding one room in a region.
- Example: ** Ostrich - Updating backdrop conditions manually.
This is a simple extension to allow rules for determining whether a backdrop is present in a particular room. Such a backdrop should be declared as a "conditional backdrop". By default, these will not be present in any room. This can be changed by adding backdrop condition rules for the objects. Such a rule should conclude with the phrases "it is present" or "it is absent" to make a decision. For testing conditions, "new location" should be used instead of location:
The sky is a conditional backdrop.
A backdrop condition for the sky: if the new location is the yard, it is present.
Note: Backdrops are only automatically updated at certain times (such as when moving from one room to another). If a backdrop condition can change under other circumstances, this must be updated manually by using the "move floating objects rule".