A while ago I was looking at callbacks for the first time and wrote this little demo to test some things. Anyway I figure it might be useful to others so here is the code.
'A short demo to show how to setup certain callbacks in Blitzmax
' and how to associate an instance of a type with an entity which can hold additional info
' use wasd,lshift and space to move camera
' keys r,g,b to send message to entity (to change colour)
'count1 updates for every entity update
'count2 updates when entity is in defined range of camera and name of entity matches simple.name
Framework leadwerks.engine