Strict
Global scnx = 640
Global scny = 480
Graphics scnx,scny
SetBlend ALPHABLEND
SeedRnd MilliSecs()
Type StarField
Global Stars:TList = CreateList()
Field x,y,a#
Method New()
ListAddLast Stars,Self
End Method
Method _draw(gx#,gy#,gscale# = 1.0)
Local tx = x+(gx*a)
Local ty = y+(gy*a)
If tx < 0 Then tx = scnx+(tx Mod scnx)
If tx > scnx Then tx = (tx Mod scnx)
If ty < 0 Then ty = scny+(ty Mod scny)
If ty > scny Then ty = (ty Mod scny)
SetAlpha a
If gscale*a < 1.0 Then
Plot x+(gx*a),y+(gy*a)
Else
DrawOval x+(gx*a),y+(gy*a),gscale*a,gscale*a
EndIf
SetAlpha 1
End Method
Function draw(gx#,gy#,gscale# =1.0)
For Local tmpStar:Starfield = EachIn Stars
tmpStar._draw gx,gy,gscale
Next
End Function
Function Fill(num_of_stars% = 100)
For Local i = 0 To num_of_stars
Local tmpStar:Starfield = New starfield
tmpStar.x = Rand(0,scnx)
tmpStar.y = Rand(0,scny)
tmpstar.a = Rnd(0.1,0.9)
Next
End Function
End Type
'--------------------------------------------------
' Example Program, arrow keys to scroll around
Local sX# = 0
Local sY# = 0
Starfield.Fill
While (Not KeyHit(key_Escape)) And (Not AppTerminate())
Cls
Starfield.draw sX, sY, 3 ' closer stars are 3 pixels wide, further stars get smaller.
'Starfield.draw sX. sY ' every star is a single pixel
If KeyDown(Key_Left) Then sX :+ 2.5
If KeyDown(Key_Right) Then sX :- 2.5
If KeyDown(Key_Up) Then sY :+ 2.5
If KeyDown(Key_Down) Then sY :- 2.5
DrawText Int(sX) +" , "+Int(sY) , 0,0
Flip
Wend |
