7 AI steering behaviors

Community Forums/Showcase/7 AI steering behaviors

Drak (Posted 2012) [#1]

I coded this about 2 years ago for my own learning purposes. Just thought I would share it with everyone. Here's the *short* worklog on it: In this simulation I will attempt success of 7 specific steering commands ;------------------------------------------------------------------------ 1.seek 2.flee 3.arrive 4.wander 5.cohesion 6.alignment 7.seperation ;------------------------------------------------------------------------ These will all be functions that will return the required vector (degree) and velocity to the movement and acceleration functions. 1. SEEK Seek will calculate the needed velocity and vector needed to arrive at the target destination. 2. FLEE Opposite of seek, flee will calculate the vector and velocity needed to move away from the target 3. ARRIVE Arrive will smoothly decelerate to the required target. 4. WANDER Move randomly with no specific target. 5. COHESION Move to the center of mass of neighbors 6. ALIGNMENT Maintain heading with neighbors 7. SEPERATION Maintain a certain distance from neighbors. Here is the code: It requires no media. Note that the keys 1-5 change the state of the bots. For alignment (key5) to work correctly it must be used AFTER cohesion with seperation. (key4) ;Originally coded 10/2010 by Drak ;Drak's STEERING BEHAVIOR RELEASED 11/30/2012 ;---------------------------------------------------------------------------------------- AppTitle "Botz Steering Examples v.0a ","Close the program?" Graphics3D 800,600,16,2 SetBuffer BackBuffer() SeedRnd MilliSecs() MoveMouse 400,300 Global trebuchet_small = LoadFont ("trebuchet MS",16) ;and this is for the messagebox SetFont trebuchet_small ;set the font to the loaded copperplate ;------------------------------------------------- ;CONSTANTS ;------------------------------------------------- Const max_bots = 40 ;maximum # of bots in simulation ;------------------------------------------------- ;GLOBALS ;------------------------------------------------- Global new_message = 0 ;Do NOT change, this is for the message box function Global startup = 0 ;leave at 0 Global action = 1 ;this refers to an action selection for each demonstration action ;------------------------------------------------- ;STARTUP ;------------------------------------------------- ;LIGHTS AND CAMERA Global light = CreateLight() RotateEntity light, 90,0,0 Global camerapivot = CreatePivot Global camera = CreateCamera(camerapivot) RotateEntity camera, 90,0,0 PositionEntity camera, 0,100,0 ;BOT MESH Global bot_mesh = CreateSphere() Global bot_nose = CreateSphere(8,bot_mesh) ScaleEntity bot_nose,.3,.3,.3 MoveEntity bot_nose,0,0,1 EntityColor bot_nose, 100,0,0 EntityColor bot_mesh, 175,0,0 HideEntity bot_mesh Global center = CreateSphere() ;------------------------------------------------- ;TYPES ;------------------------------------------------- Type bot Field mesh ;holds the actual model of the bot Field target ;holds the bot's target entity # Field mass# Field velocity# Field max_velocity# Field acceleration# Field max_acc# Field turn# Field max_turn# Field status Field steer_ball Field steer_pivot Field steer_setup Field steer_angle# End Type ;------------------------------------------------- ;COLLISIONS ;------------------------------------------------- ;------------------------------------------------- ;MESSAGE BOX, Create a 7 line message box ;------------------------------------------------- Dim mb_box$(7) ;create a 7 dimention array ;whatever is typed in here will be displayed at program launch mb_box$(0) = "" ;give them all nothing by using "" mb_box$(1) = "" ; mb_box$(2) = "" ; mb_box$(3) = "" ; mb_box$(4) = "" ; mb_box$(5) = "" ; mb_box$(6) = "Steering Demonstration. Keys 1-5 change bot status. Starting in mode #2, which is Flee." ;This is the starting message that appears in the message box Global old1$=0 ;DO NOT alter any of these lines Global old2$=0 ;DO NOT alter any of these lines Global old3$=0 ;DO NOT alter any of these lines Global old4$=0 ;DO NOT alter any of these lines Global old5$=0 ;DO NOT alter any of these lines Global old6$=0 ;DO NOT alter any of these lines Global old7$=0 ;DO NOT alter any of these lines ;------------------------------------------------- ;MAINLOOP! ;------------------------------------------------- While Not KeyHit(1) startup() get_input() update_bots() UpdateWorld RenderWorld mb_scroll() Flip False Wend ;----------------------------------------------------------------------------------------------------- ;MESSAGE BOX ;----------------------------------------------------------------------------------------------------- Function mb_scroll() SetFont trebuchet_small If new_message = 1 ;if we have a new message in que mb_box(5) = old6$ ;box 5 will now equal what box 6 was before mb_box(4) = old5$ ;and so on... mb_box(3) = old4$ mb_box(2) = old3$ mb_box(1) = old2$ mb_box(0) = old1$ ;till the end new_message = 0 ;reset the new message flag End If Text 10, 525, mb_box(0) ;1 Text 10, 535, mb_box(1) ;2 Text 10, 545, mb_box(2) ;3 Text 10, 555, mb_box(3) ;4 Text 10, 565, mb_box(4) ;5 Text 10, 575, mb_box(5) ;6 Text 10, 585, mb_box(6) ;7th and new line old1$ = mb_box(1) ;store these strings in another variable for the next loop old2$ = mb_box(2) old3$ = mb_box(3) old4$ = mb_box(4) old5$ = mb_box(5) old6$ = mb_box(6) End Function ;----------------------------------------------------------------------------------------------------- ;STARTUP ;----------------------------------------------------------------------------------------------------- Function startup() If startup = 0 ;if flagged as 0 For num = 1 To max_bots ;do this the (max_bots) times b.bot = New bot ;create a new bot b\mesh = CopyEntity(bot_mesh) ;copy the predefined mesh for the body EntityColor b\mesh, Rand(175),Rand(175),Rand(175) ;pick a lovely color b\mass = .5 ;set it's mass b\velocity = Rnd(.01,.015) ;give it a random velocity b\max_velocity = Rnd(.8,1.2) ;and set it's max velocity b\acceleration = 0 ;acceleration is at 0 b\max_acc = Rnd(.008,.013) ;max acceleration is set here b\turn = 0 ;turn is 0 b\max_turn = Rnd(.08,.12) ;max turn angle b\status = 2 ;set the status as #2 b\steer_setup = 0 ; PositionEntity b\mesh,Rand(-50,50),0,Rand(-50,50) ;set the position randomly Next startup = 1 ;then flip the startup flag to 1 so we don't repeat this code End If End Function ;----------------------------------------------------------------------------------------------------- ;UPDATE BOTS ;----------------------------------------------------------------------------------------------------- ;We will only act upon the selected status and steering selection. No other ;factors will affect the bots in this simulation. Function update_bots() For b.bot = Each bot Select b\status ;CASE 1 IS SEEK STEERING Case 1 ;we'll use the central object for the target ;so, first get the delta yaw to turn the bot to the center object Local deltay# = DeltaYaw(b\mesh,center) ;store this in a floating point variable Local dist# = EntityDistance(b\mesh,center) ;get the distance also, and store it If deltay > .1 ;if the angle is > 0 b\turn = b\turn + .001 If b\turn > b\max_turn Then b\turn = b\max_turn ElseIf deltay < -.1 ;if the angle is < 0 b\turn = b\turn - .001 If b\turn < -b\max_turn Then b\turn = -b\max_turn End If ;turn the entity the desired direction TurnEntity b\mesh, 0,b\turn,0 If dist >= 10 b\acceleration = b\acceleration + .00001 If b\acceleration > b\max_acc Then b\acceleration = b\max_acc b\velocity = b\acceleration ;BY ADDING THE NEXT ELSE IFs, WE CAN DECELERATE (3=ARRIVE) SLOWLY Else If dist < 10 And dist > 2 b\acceleration = b\acceleration - .00001 If b\acceleration < .001 Then b\acceleration = .001 b\velocity = b\acceleration Else If dist <= 2 b\acceleration = b\acceleration - .00001 If b\acceleration <= 0 Then b\acceleration = 0 b\velocity = b\acceleration End If MoveEntity b\mesh, 0,0,b\velocity ;CASE 2 IS FLEEING Case 2 ;this is essentially the same as seek, only backwards Local deltay2# = DeltaYaw(b\mesh,center) ;store this in a floating point variable Local dist2# = EntityDistance(b\mesh,center) ;get the distance also, and store it If deltay2 < 0 ;if the angle is > 0 b\turn = b\turn + .001 If b\turn > b\max_turn Then b\turn = b\max_turn ElseIf deltay2 > 0 ;if the angle is < 0 b\turn = b\turn - .001 If b\turn < -b\max_turn Then b\turn = -b\max_turn End If ;turn the entity the desired direction TurnEntity b\mesh, 0,b\turn,0 If dist2 < 50 b\acceleration = b\acceleration + .00001 If b\acceleration > b\max_acc Then b\acceleration = b\max_acc b\velocity = b\acceleration ;BY ADDING THE NEXT ELSE IFs, WE CAN DECELERATE (3=ARRIVE) SLOWLY Else If dist2 > 50 b\acceleration = b\acceleration - .00001 If b\acceleration < .001 Then b\acceleration = .001 b\velocity = b\acceleration End If MoveEntity b\mesh, 0,0,b\velocity ;CASE 3 IS WANDERING Case 3 ;This can be easily overcomplicated, so lets keep it simple b\steer_angle = b\steer_angle + Rnd(-.01,.01) ;simply adjust the steering angle slightly If b\steer_angle > .1 Then b\steer_angle = .1 ;and keep it within a reasonalble amount If b\steer_angle < -.1 Then b\steer_angle = -.1 ;same... TurnEntity b\mesh,0,b\steer_angle,0 ;then turn it... MoveEntity b\mesh,0,0,b\max_acc ;and move it! Easy! ;CASE 4 IS COHESION Case 4 Local closest# = 1000 ;start at 1000 ;Here we get the Nearest bot For n.bot = Each bot If b\mesh <> n\mesh Local dist_n# = EntityDistance(b\mesh, n\mesh) ;get distance to each bot If dist_n < closest ;if the distance is smaller than the previous smallest closest = dist_n b\target = n\mesh End If End If Next ;And move it towards that nearest bot ;HERE IS THE #7 SEPERATION VALUE, (3 UNITS) If closest > 3 Local d3# = DeltaYaw(b\mesh,b\target) ;store this in a floating point variable If d3 > .1 ;if the angle is > 0 b\turn = b\turn + .001 If b\turn > b\max_turn Then b\turn = b\max_turn ElseIf d3 < -.1 ;if the angle is < 0 b\turn = b\turn - .001 If b\turn < -b\max_turn Then b\turn = -b\max_turn End If ;turn the entity the desired direction TurnEntity b\mesh, 0,b\turn,0 If closest >= 7 b\acceleration = b\acceleration + .00001 If b\acceleration > b\max_acc Then b\acceleration = b\max_acc Else If closest < 7 b\acceleration = b\acceleration - .00001 If b\acceleration < 0 Then b\acceleration = 0 End If b\velocity = b\acceleration MoveEntity b\mesh,0,0,b\velocity End If ;HERE IS #6 ALIGNMENT WITH NEIGHBORS ;(this only works correctly AFTER using case 4, cohesion) Case 5 If b\target <> 0 Local vector# = EntityYaw(b\target,1) Local my_vector# = EntityYaw(b\mesh,1) If my_vector > vector ;if more b\turn = b\turn - .001 If b\turn > b\max_turn Then b\turn = b\max_turn ElseIf my_vector < vector ;if less b\turn = b\turn + .001 If b\turn < -b\max_turn Then b\turn = -b\max_turn End If ;turn the entity the desired direction TurnEntity b\mesh, 0,b\turn,0 End If End Select Next End Function ;----------------------------------------------------------------------------------------------------- ;GET INPUTS ;----------------------------------------------------------------------------------------------------- Function get_input() If KeyHit(2) new_message = 1 mb_box(6) = "Steering set to SEEK. Bots will SEEk to the center sphere." For b.bot = Each bot b\status = 1 Next End If If KeyHit(3) new_message = 1 mb_box(6) = "Steering set to FLEE. Bots will FLEE from the center sphere." For b.bot = Each bot b\status = 2 Next End If If KeyHit(4) new_message = 1 mb_box(6) = "Steering set to WANDER. Bots will wander aimlessly." For b.bot = Each bot b\status = 3 Next End If If KeyHit(5) ;4 new_message = 1 mb_box(6) = "Steering set to COHESION WITH SEPERATION. Bots will move to the center of mass with it's neighbors." For b.bot = Each bot b\status = 4 Next End If If KeyHit(6) ;5 new_message = 1 mb_box(6) = "Steering set to ALIGNMENT WITH NEIGHBORS. Bots will attempt to align themsleves with their neighbors." For b.bot = Each bot b\status = 5 Next End If End Function Last edited 2012 Last edited 2012

zoqfotpik (Posted 2012) [#2]

This is very interesting. Thanks a lot, it will come in extremely handy.

Why0Why (Posted 2012) [#3]

Very Cool! Thanks for posting. I have considered and Autoduel remake for years and that would be a great addition.