Newbie question: Detecting object proximity.

[radbrad]

Hello, I have finally decided to make my first game. A tower defense games. Bad guys move along a pre determined path. You place your towers (guns, rockets, etc) along the path so when the bad guys pass by the towers shoot at the bad guys.

My question: How can I determing when a bad guy is passing close to a tower, to make it start shooting?

Any help would be greatly appreciated.
Radbrad

[RickyRombo]

You can use the Advanced Direction Object or the Clickteam Movement Controller to test if the distance between two objects is "in range"

[radbrad]

Thanks RickyRombo, now how do I use them? Can you point me to the any kind of documentation?

CHeers,
Radbrad

[uprize]

Download advanced direction object and check out the example files that come with it.

[Anders]

You could also make some circle shaped active objects and make the invisible. That is what many people on theese forums call a 'detector' since you can use it to test for collisions even though it is invisible.

+ Every 00:00:40
+ 'Enemy' is overlapping 'detector'
+ Fixed value of 'Tower' is equal to towerId('detector')
--> Tower: Shoot at enemy

You have to store the fixed value of the tower that the detector belongs to into some alterable value. In the above example I call it 'towerId' but you can call it whatever you want.

[radbrad]

Hey Andros First of all thank you for the solution.

Sounds good but and there is aways a but, If I have to create an invisable object at the same X and Y coordinance as the tower to use as detector sounds like alot more work.

I tried to create a large active object then erease it and make a small square in the center for testing, leaving a large mask around the square. The tower ignores the mask. Is ther a way for the object not to ignore the large invisable mask around the active object?

[uprize]

A circle invisible object works but is not really a very good option. This is unneccesary as it increases memory usage and adds to your object limit and will cause lag with lots of objects. Use triginometry instead. Advanced direction calculator is easy.
All you have to do is spread value 0 in all towers and fastloop through them. Then calculate if an enemy is within a certain distance from it.

[radbrad]

Is there any demo's you can point me to or some documentation I can read to understand how to put the trig in to the expression calculator. Maybe just a basic understanding of advanced direction calculator.

Thanks again, you guys are great.

Oh, I have a single level of the game almost totaly functional. Still polishing though for folks with lesser P.C.'s out there etc. This first go round is to teach myself MMF2. More of a prof of concept and to build my own demo library of little programs so I can remember how I got things to work. With the help of the great folks here at the Forums.
Thank you again for your time and effort.

Brad

[Atom]

I made a range check/compare widget a while back -

http://www.clickteam.com/epicenter/ubbthreads.php?ubb=showflat&Number=112668#Post1126 68

Not sure if the widget will help but maybe. There is also a few examples in the files area which are for this sort of thing -

http://www.clickteam.com/epicenter/ubbthreads.php?ubb=showflat&Number=153140

http://www.clickteam.com/epicenter/ubbthreads.php?ubb=showflat&Number=146329

Hope this helps

[radbrad]

I want to thank everyone who posted here for me. I really do appreicait you taking the time to help.

Brad