Cape simulation

Monkey Forums/Monkey Code/Cape simulation

SLotman

(Posted 2014) [#1]

Just had this crazy idea tonight, to do a basic 2D cape simulation... found nothing on Google, so this is what I came up with: the game is a bunch of segments, as as the root segment moves, all child segments are updated accordingly.

It kinda of work... but I think I'm missing something, the movement isn't fluid enough. Take a look at what I coded, and if someone can suggest something (besides using a physics engine :P) I'm all ears :)

Import mojo

#If TARGET="glfw"
	#GLFW_USE_MINGW=True
	#GLFW_WINDOW_TITLE="Cape Simulation Test"
	#GLFW_WINDOW_WIDTH=1024
	#GLFW_WINDOW_HEIGHT=768
	#GLFW_WINDOW_FULLSCREEN=False
	#MUSIC_FILES="*.wav|*.ogg"
#End

Global gravity:Float = 0.7

Class CapePoint
	Field x:Float, y:Float

   Method New()
   End Method

   Method New(x:Float, y:Float)
      Self.x = x
      Self.y = y
   End Method
End Class

Class CapeNode
   Field p1:CapePoint
   Field p2:CapePoint
   Field child:CapeNode
   Field length:Float
   Field transmission:Float ' how much energy passes from one node to another
   
   Method New(x:Float, y:Float, length:Float)
   	Self.p1 = New CapePoint(x,y)
   	Self.p2 = New CapePoint(x,y+length)
   	Self.length = length
   	Self.child = Null
   End Method
   
   Method draw()
   	For Local c:Int=0 To 19
      	DrawLine p1.x+c, p1.y, p2.x+c, p2.y   
   	Next

   	If (child) Then child.draw()	
   End Method
   
   Method move(x:Float, y:Float)
   	' here the magic happens
   	p1.x +=x
   	p1.y +=y   	
   End Method
   
   Method update(parent:CapeNode=Null)
   	If parent Then   	
   		p1.x = parent.p2.x
   		p1.y = parent.p2.y   		   		
   	End If

		p2.y +=gravity*2.5
   	If (p1.x - p2.x) > length Then 
   	   p2.x = p1.x - length 
   	Else
   		p2.x += (p1.x - p2.x)*transmission
   	End If	   	

   	If Abs(p2.y - p1.y) > length Then 
   	   If p1.y > p2.y Then p2.y = p1.y - length Else p2.y = p1.y + length   	  
   	Else
   	   If p2.y < p1.y+length Then p2.y+=gravity + 2*(0.5 + transmission)
   	End If	   	

   	If (child) Then child.update(Self)
   End Method
End Class

Class Cape
   Field root:CapeNode

   Method setPos(x:Float, y:Float)
   	root.p1.x = x
   	root.p1.y = y
   End Method
   
   Method move(x:Float, y:Float)
   	root.move(x,y)
   End Method
   
   Method draw()
   	root.draw()
   End Method
   
   Method update()
   	root.update()
   End Method
End Class

Class Player
	Field x:Float, y:Float
	Field speedX:Float, speedY:Float
	
	Field cape:Cape
	
	Method New(x:Float, y:Float)
		Self.x = x
		Self.y = y
		
		Self.cape = New Cape()
		Self.cape.root = New CapeNode(x-35,y-10, 10)
		Self.cape.root.transmission = 0.5
		
		Self.cape.root.child = New CapeNode(x-35,y,15)
		Self.cape.root.child.transmission = 0.4
		
		Self.cape.root.child.child = New CapeNode(x-35,y+15,20)
		Self.cape.root.child.child.transmission = 0.3

		Self.cape.root.child.child.child = New CapeNode(x-35,y+35,20)
		Self.cape.root.child.child.child.transmission = 0.25
	End Method
	
	Method update()
		x += speedX
		y += speedY
		cape.move(speedX, speedY)

		speedX*=0.90
		If Abs(speedX)<0.05 Then speedX=0

		speedY*=0.90
		If Abs(speedY)<0.05 Then speedY=0
		
		cape.update()
	End Method
	
	Method draw()
		'DrawCircle x, y, 30
		SetColor 0,0,255
		DrawRect x-25,y-15,15,80
		DrawRect x-10,y+55,10,10
		
		SetColor 208,148,0
		DrawRect x-25, y-35,25,20
		
		SetColor 255,0,0
		cape.draw()
		SetColor 255,255,255
	End Method
End Class

Class Game Extends App
	Field player:Player
	
	Method OnCreate()
		SetUpdateRate(60)
		player = New Player(100,300)
		player.speedX = 0
	End Method
	
	Method OnRender()
		Cls
		player.draw()		
		DrawText "Cape simulation test",10,10
	End Method
	
	Method OnUpdate()
		player.update()
		
		If KeyDown(KEY_RIGHT) And player.speedX<4 Then player.speedX+=1.0
		If KeyDown(KEY_LEFT) And player.speedX>-4 Then player.speedX-=1.0

		If KeyDown(KEY_UP) And player.speedY<4 Then player.speedY-=1.0
		If KeyDown(KEY_DOWN) And player.speedY>-4 Then player.speedY+=1.0
		
		If KeyHit(KEY_ESCAPE) Then Error ""
	End Method
End Class

Function Main()
	New Game()
End Function

therevills

(Posted 2014) [#2]

The effect isn't bad, it might look cool on a 32x32 sprite :) I think the cape settles too fast.

Also, apart from the music files pre-processor you don't need to wrap the #GFLW pre-processors in the #If statement, the other targets will just ignore them.

SLotman

(Posted 2014) [#3]

Oh, those pre-processors I just copied from another project, feel free to ignore them :)

Why0Why

(Posted 2014) [#4]

That is really nice! Thanks for sharing.