Monkey-X - Matrix/SetAlpha/Rotate/Translate Effect - code example

Here a short example of how to make effects with Monkey. In this example rectangles are shot up from the center of the screen, they rotate and then they fall down. The SetAlpha is used so they are transparent.

Code below :

Import mojo

Const screenwidth:Int=640
Const screenheight:Int=480

Class effect
    Field x:Float
    Field y:Float
    Field incx:Float
    Field incy:Float
    Field w:Int
    Field h:Int
    Field col:Int
    Field angle:Int=Rnd(-180,180)
    Field angleturn:Int
    Field delete:Bool = False
    Method New(_x:Float,_y:Float,_w:Int,_h:Int)
        x = _x
        y = _y
        w = _w
        h = _h
        col = Rnd(50,150)
        incx = Rnd(-2,2)
        incy = Rnd(-10,-5)
        angleturn = Rnd(-5,5)
    End Method
    Method update()
        angle+=angleturn
        If angle>180 Then angle=-180
        If angle<-180 Then angle=180
        x+=incx
        y+=incy
        incy+=.1
        If y>screenheight Then delete = True
        For Local i:=Eachin e
            If i.delete = True Then e.Remove i
        Next
    End Method
    Method draw()
        PushMatrix()
        Translate x,y
        Rotate(-angle)
        Translate -x,-y
        SetColor 10+col,0,0
        SetAlpha 0.5 'part transparent setting
        DrawRect x,y,w,h
        PopMatrix()
        SetAlpha 1 'restore transparent setting to none transparent
    End Method
End Class

Global e:List<effect> = New List<effect>

Class MyGame Extends App

    Method OnCreate()
        SetUpdateRate(60)
    End Method
    Method OnUpdate()        
        If Rnd(10) < 2 Then e.AddLast(New effect(320,240,Rnd(5,25),Rnd(5,25)))
        For Local i:=Eachin e
            i.update
        Next
    End Method
    Method OnRender()
        Cls 0,0,0 
        For Local i:=Eachin e
            i.draw
        Next
        SetColor 255,255,255
    End Method
End Class


Function Main()
    New MyGame()
End Function