Monkey-X - Example - Boids Flocking - code example

' Converted to Monkey-X - from Blitzmax ( coded originally by Flanker)
'

Import mojo

Class obstacle
    Field x:Float,y:Float
    Field radius:Int
    Method New(x:Int,y:Int)
        Self.x = x
        Self.y = y
        Self.radius = 20    
    End Method
    Method draw()
        SetColor 255,255,0
        DrawCircle(x,y,radius)
    End Method    
End Class

Class boid
    Field friendlist:List<boid> = New List<boid>
    Field x:Float,y:Float,angle:Float
    Field vx:Float,vy:Float
    Field alignspeed:Float = 8
    Field speed:Float = 3
    Field smoothturn:Float = 25
    Field radius:Float = 10
    Field cohesionfactor:Float = 100
    Field friendradius:Float = 75
    Field frienddistance:Float = 30
    Field friendsqradius:Float
    Field friendsqrdistance:Float
    Field obstaclemargin:Float = 2
    Method New()
        friendsqradius = friendradius*friendradius
        friendsqrdistance = frienddistance*frienddistance
    End Method
    Method create(count:Int)
        For Local i:=0 Until count
            Local newboid:boid = New boid()
            newboid.x = Rnd(640)
            newboid.y = Rnd(480)
            newboid.angle = Rnd(360)
            boidlist.AddLast(newboid)
        Next
    End Method
    Method update()
        getfriends()
        If friendlist.Count > 0
            vx = 0
            vy = 0
            cohesion()
            obstacle()
            distance()
            align()
        Else
            obstacle()
        End If        
        ' Clamp the movement speed
         If vx < -2 Then vx = -2 
         If vy < -2 Then vy = -2
         If vx > 2 Then vx = 2
         If vy > 2 Then vy = 2
        move()
    End Method
    Method obstacle()
        For Local i:=Eachin myobstacle
            Local diffx:Float = x - i.x
            Local diffy:Float = y - i.y
            Local sqrdistance:Float=diffx*diffx+diffy*diffy
            If diffx*diffx+diffy*diffy < i.radius*i.radius*i.radius/obstaclemargin
                vx -= (i.x - x) / Sqrt(sqrdistance) 
                vy -= (i.y - y) / Sqrt(sqrdistance)
            End If
        Next
    End Method
    Method cohesion()
        Local centerx:Float
        Local centery:Float
        For Local i:= Eachin friendlist
            centerx += i.x
            centery += i.y
        Next
        centerx /= friendlist.Count
        centery /= friendlist.Count
        vx += (centerx-x) / cohesionfactor
        vy += (centery-y) / cohesionfactor
    End Method
    Method distance()
        For Local i:=Eachin friendlist
            Local diffx:Float=x-i.x
            Local diffy:Float=y-i.y
            Local sqrdistance:Float=diffx*diffx+diffy*diffy
            If diffx*diffx+diffy*diffy < friendsqrdistance
                vx -= (i.x - x) / Sqrt(sqrdistance)
                vy -= (i.y - y) / Sqrt(sqrdistance)
            End If
        Next
    End Method
    Method align()
        Local sumvx:Float
        Local sumvy:Float
        For Local i:=Eachin friendlist
            sumvx += i.vx
            sumvy += i.vy
        Next
        sumvx /= friendlist.Count
        sumvy /= friendlist.Count
        vx += (sumvx - vx) / alignspeed
        vy += (sumvy - vy) / alignspeed
    End Method
    Method move()
         x += vx
        y += vy
        angle = smoothrotate(x,y,angle,x+vx,y+vy,smoothturn)
        x += Cos(angle) * speed
        y += Sin(angle) * speed
        If x<0 Then x = 640
        If y<0 Then y = 480
        If x>640 Then x = 0
        If y>480 Then y = 0
    End Method
    Method getfriends()
        friendlist.Clear()
        For Local i:=Eachin boidlist
            Local diffx:Float=x-i.x
            Local diffy:Float=y-i.y            
            If diffx*diffx+diffy*diffy < friendsqradius
                If i <> Self Then 
                    friendlist.AddLast(i)
                End If
            End If
        Next
    End Method
    Method updateall()
        For Local i:=Eachin boidlist
            i.update
        Next
    End Method
    Method drawall()
        For Local i:=Eachin boidlist
            i.draw
        Next
    End Method
    Method draw()
        SetColor 255,255,255
        DrawCircle(x,y,10)
    End Method
    Function smoothrotate:Float(sourceX:Float,sourceY:Float,sourceAngle:Float,destX:Float,destY:Float,smooth:Float)
        ' Thanks to BlackSp1der on BB forums for this piece of code ! <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
        Local targetAngle:Float = ATan2(sourceY-destY,sourceX-destX)
        Local tempAngle:Float = targetAngle - Sgn(targetAngle-sourceAngle) * 360
        If Abs(targetAngle-sourceAngle) > Abs(tempAngle-sourceAngle) Then targetAngle = tempAngle
        If sourceAngle <> targetAngle Then sourceAngle = sourceAngle - Sgn(targetAngle-sourceAngle) * (180-Abs(targetAngle-sourceAngle)) / (1+smooth)
        If sourceAngle >= 360 Then sourceAngle -= 360 Else If sourceAngle < 0 Then sourceAngle += 360
        Return sourceAngle
    End Function    
End Class

Global myobstacle:List<obstacle>
Global boidlist:List<boid> = New List<boid>

Class MyGame Extends App
    Field myboid:boid
    Method OnCreate()
        SetUpdateRate(60)
        myobstacle = New List<obstacle>
        For Local i:Int = 0 Until 10
            myobstacle.AddLast(New obstacle(Rnd(640),Rnd(480)))
        Next
        myboid = New boid()
        myboid.create(20)
    End Method
    Method OnUpdate()
        myboid.updateall()     
        If MouseDown(MOUSE_LEFT) Then myobstacle.AddLast(New obstacle(MouseX,MouseY))
        If KeyHit(KEY_SPACE) Then 
            For Local i:Int = 0 Until 10
                myobstacle.AddLast(New obstacle(Rnd(640),Rnd(480)))
            Next
        End If
    End Method
    Method OnRender()
        Cls 0,0,0 
        SetColor 255,255,255
        myboid.drawall()
        For Local i:=Eachin myobstacle
            i.draw
        Next
        SetColor 255,255,255
        DrawText "Hold LMB to draw obstacles.",0,0
        DrawText "Press space for random obstacles.",0,20
    End Method
End Class

Function Main()
    New MyGame()
End Function