Snowing Effect in Monkey X

Since Christmas is coming soon, I decided to share my snowing effect code I wrote last year. The original code was written in BlitzMax. This year I have already made new Christmas intro in Monkey X. You may want to take look at the snowing effect of the Christmas video of the last year.

Import mojo2

Function Main()
	New MyApp
End

Class snowFlake
	Field x:Float, y:Float
	Field dx:Float
	Field r:Int
	Field yspeed:Float
	Field flakeAngle:Float
End Class

Class MyApp Extends App

	Field gfxBG:Image
	Field canvas:Canvas
	
	Global flakeList := New List<snowFlake>
	
	Method OnCreate()

		SetDeviceWindow(640,480,0)		
		canvas = New Canvas
		
		gfxBG = Image.Load("bg.jpg",.0,.0)
			
		For Local i = 0 To 149
			Local flake:snowFlake = New snowFlake
			flake.x = Rnd(50,640-50)
			flake.r = Rnd(2,8)
			flake.y = -flake.r * 2
			flake.yspeed = Rnd(0.7,3)
			flake.flakeAngle = Rnd(0,359)
			flakeList.AddLast(flake)
		Next
		
		SetUpdateRate(30)
		
	End
	
	Method OnUpdate()
		
	End
	
	Method OnRender()
		
		canvas.PushMatrix()
		canvas.Scale(DeviceWidth() / 640.0, DeviceHeight() / 480.0)
		canvas.SetAlpha 1
		canvas.SetBlendMode(BlendMode.Opaque)
		canvas.DrawImage(gfxBG,0,0)
		
		For Local flake:snowFlake = Eachin flakeList
		
			flake.x = flake.x + flake.dx
			flake.y = flake.y + flake.yspeed
			
			canvas.DrawCircle flake.x, flake.y, flake.r
			flake.dx = Cos(flake.flakeAngle) * 4 * Rnd(0.2,1)

			If flake.y >= 480 + flake.r * 2 Then
				flake.r = Rnd(2,8)
				flake.y = -flake.r * 2
			Endif

			flake.flakeAngle = flake.flakeAngle + 1
		
		Next
		
		canvas.PopMatrix()
		canvas.Flush()

		
	End
	
End Class

Examine the code and you’ll get the idea quickly. Implementation in other programming languages should be quit straight forward. Just use background picture of your own.

Feel free to use the code.

Screenshot of the program:

I will soon publish my new Merry Christmas 2017 and Happy New Year 2018 video. And… It’s also written in Monkey X.