I’ve been using asGamer’s excellent set of game design tutorials to put together a basic ‘ship and enemies’ shoot 'em style game - my first proper venture into using AS3 and external class files - and I’ve hit a problem with executing hit test results.
To explain…
The game uses Engine (the document class), Ship and Enemy classes. Enemies (new instances of the Enemy class) are added to the stage in the Engine class, where they are also stored in an array, enemyList. The Ship fires a Laser, and the Laser class is where we test for a hit on Enemies. Now, in asGamer’s original version he uses the hitTestObject to test for hits, and if a hit is registered, this line
Engine.enemyList*.takeHit();
calls a funtion in the Enemy class to remove the relevany clip. However, as the hitTestObject includes the bounding box of a clip in its hit test, I decided to use Corey O’Neil’s Collision Detection Kit for greater accuracy. The CDK CollisionList class returns an array, the each element of which is a clip with which the target object has collided.
The problem this presents is that rather than using
Engine.enemyList*.takeHit();
to deal with a collision, I now use
collisions[j].object1.takeHit();
where ‘collisions[n].object1’ are the movie clips hit. When I test the game it throws an error
ReferenceError: Error #1069: Property takeHit not found on com.asgamer.basics1.Laser and there is no default value.
at com.asgamer.basics1::Laser/loop()
- although the movie does not break, and continues to remove destroyed enemies as if there was no problem.
Could anyone explain exactly what the problem is with calling the takeHit function via the collisions array rather than the Engine.enemyList array? And perhaps suggest a way to prevent it?
I should point out that the ‘laser’ is in fact a blast that can take out any number of enemies intersecting with the blast radius, which is why I’m using CollisionList to detect hits.
Thanks in advance to anyone able to help
