How to make 2D AI - GameCreators Forum

Author

Message

vitinho444

13

Years of Service

User Offline

Joined: 12th Oct 2010

Location:

Posted: 12th Jul 2011 21:36

Link

Hey guys, i was wondering how can i add to my 2D Game some AI to the CPU Controlled enemies.

When i say AI i mean like random walk, attack and stuff...

PS: I know the DarkAI but it just says 3D AI and the Demo doesnt Work.

Learning C++
VB6 Advanced: 4/5
VB.NET Advanced: 4/5

Back to top

Profile PM Email Website

WLGfx

16

Years of Service

User Offline

Joined: 1st Nov 2007

Location: NW United Kingdom

Posted: 12th Jul 2011 23:46

Link

I've used pseudo AI states for characters ie:

+ Code Snippet

switch (character.state)
case state_move_forward:
  ...move character forward
  ...decrement the count
  ...if count reaches 0 then change AI state
case state_turn_around:
  ...turn character around a little bit
  ...decrement the counter
  ...if counter reaches 0 then change AI state
case state_do_nothing:

and so on... You can have a state following another controlling state so that if the player finishes moving forward then it will stop and do nothing for a bit before deciding to do something else.

The only limit to what you can do with AI states is your imagination.

Warning! May contain Nuts!

Back to top

Profile PM Email Website

vitinho444

13

Years of Service

User Offline

Joined: 12th Oct 2010

Location:

Posted: 13th Jul 2011 01:28

Link

ahh
so character.state = random number then it just does something for a certain time and then random again ?

hum i never see things like that xD

Nice nice, thanks a lot, but.. i never learn select case on C++ can u say the full thing or its just

switch (name)
case Me:
dbText (85723847364,39572349, "Vitinho444");

case You:
dbText (85723847364,39572349, "WLGfx");

case Wrapper:
dbText (85723847364,39572349, "DarkGDK");

?

Learning C++
VB6 Advanced: 4/5
VB.NET Advanced: 4/5

Back to top

Profile PM Email Website

WLGfx

16

Years of Service

User Offline

Joined: 1st Nov 2007

Location: NW United Kingdom

Posted: 13th Jul 2011 04:26 Edited at: 13th Jul 2011 04:27

Link

http://en.wikipedia.org/wiki/Switch_statement

It's a very useful part of C/C++ and saves writing a hell of a lot of IF statements.

Warning! May contain Nuts!

Back to top

Profile PM Email Website

Red Eye

15

Years of Service

User Offline

Joined: 15th Oct 2008

Location:

Posted: 13th Jul 2011 10:04

Link

Quote: "It's a very useful part of C/C++ and saves writing a hell of a lot of IF statements."

The main reason why you SHOULD use it, is because it is way better optimized and thus faster.

Back to top

Profile PM Email

TechLord

21

Years of Service

User Offline

Joined: 19th Dec 2002

Location: TheGameDevStore.com

Posted: 13th Jul 2011 12:52 Edited at: 13th Jul 2011 13:00

Link

Quote: "When i say AI i mean like random walk, attack and stuff... "

Hi vitinho444,

Looks like you have a solid grip on the Finite State Machine (FSMs) portion of your AI but need a Pathfinder or Waypoint System to navigate your FSM Bots. You can either code A* Pathfinding or implement a 3rd party lib like MicroPather. You could create navigation paths manually by placing waypoints in the level.

I wouldn't encourage using random values to trigger actions. You can create a pretty effective event triggering system using basic collision detection algos to activate state changes in your Bots. Raycasting and bounds collision are often used to give Bots a sense of Vision or Hearing. You can also place Triggers collision shapes in the level to trigger Bots when the player collides with them.

DarkTokens: Coin-Op (MicroTransaction) API for DBPro/DGDK

Back to top

Profile PM Email Website

vitinho444

13

Years of Service

User Offline

Joined: 12th Oct 2010

Location:

Posted: 13th Jul 2011 13:12

Link

@WLGfx and Red Eye
Big thanks to you guys