by DocRabbit » Wed Aug 01, 2007 2:18 am
In just about any first person shooter, when you walk up to a door and it opens without you touching it, you entered trigger area that is tied to the door that tells it to open. This would be the same as an invisible sensor area.
You don't see it during gameplay, but moving across it, into it, and even out of it can be used to drop an apple on your head, open a trap door, or anything else that could be tied to an event.
Common uses I use them for would be surrounding each side of the viewport with them, then triggering the viewport to move in a "Zelda like fashion". If you have played the old Legend of Zelda, when you move into a new area, you stop moving and the screen moves into the new area, leaving you at the far side(left side if you moved out the right side, top if from bottom,etc)
Look at the snake/caveman tutorial, it has good examples.
Filled regions are perfect for capturing click events on plain text actors, just remember to disable click events on the text actor, then you draw the region around the text and gives you a good rectangle to capture click events. If you have ever had difficulty clicking on menus with text, good chance regions weren't used.