Parallax scrolling

Один из способов сделать скроллинг в игре.

Платформа: Windows , Linux
Автор: angros47, fxm

Parallax scrolling.png

Dim Shared As Integer p(255, 2)

Sub Scroll()
   Dim As Ubyte Ptr target = Screenptr
   Screenlock
   For i As Integer = 0 To 800*600-2
      *(target + i) = *(target + i + 1)
   Next i
   Screenunlock
End Sub

Sub cycle (lowest As Integer, highest As Integer)
   For i As Integer = highest To lowest +1 Step -1
      swap p(i, 0), p(i-1, 0)
      swap p(i, 1), p(i-1, 1)
      swap p(i, 2), p(i-1, 2)
      Palette i, p(i, 0), p(i, 1), p(i, 2)
   Next i
   Palette lowest, p(lowest, 0), p(lowest, 1), p(lowest, 2)
End Sub


Screenres 800,600, 8


'Prepare a tile
Dim image As Any Ptr = Imagecreate( 64, 64, 0,8)
Line image,(1,1)-(63,63),6,bf
Line image,(1,1)-(63,3),15,bf
Line image,(1,1)-(3,63),15,bf

Line image,(60,3)-(63,63),4,bf
Line image,(3,60)-(63,63),4,bf

'prepare palette
For i As Integer = 129 To 144
   p(i, 0) = 128
   p(i, 1) = 64
   p(i, 2) = 64
   Palette i, p(i, 0), p(i, 1), p(i, 2)
Next i
p(130, 0) = 64
p(130, 1) = 0
p(130, 2) = 0
Palette 130, p(130, 0), p(130, 1), p(130, 2)


'main cycle

Dim As Integer i, y

Do
   i+=1
   'background
   Line (799,0)-(799,600),129+(i Mod 16),,254
   Line (799,0)-(799,600),129+((i+8) Mod 16),,254*256
   Line (799,0)-(799,600),128,,257

   
   'tile
   If (i Mod 64)=0 Then y=rnd(1)*8
   Put (799,y*64),image, (i Mod 64,0)-step(2,64),Pset

   Scroll

   If i Mod 2 Then cycle 130,144

   Sleep 5
Loop Until Multikey(1)

FreeBasic

Parallax scrolling