Advice
The glitch coused by the screen copy+single buffer, Use double buffer.
You do not have to screen copy all the frames... use HW scroll on the same screen, I think It will be faster
IX=0
IY=0
TILEMAPX=0
TILEMAPY=0
STX=0
STY=0
SCRLLSP=2
Screen Open 1,800,192,16,Lowres
Screen Display 1,128,74,320,192
Autoback 0
Double Buffer
Tile Size 16,16
TX=0 : TY=0 : BX=800 : BY=192
Map View TX,TY To BX,BY
Load "Assets/icons.abk"
Get Icon Palette
Reserve as Data 6,50*12+4
BLoad "Assets/garbage.map"
Map Do TILEMAPX,TILEMAPY
Screen Swap
Map Do TILEMAPX,TILEMAPY
Screen Swap
Do
Screen Offset 1,IX,IX
Screen Swap
Wait Vbl
if Jright(1)=-1 : Add IX,SCRLLSP : End If
if Jleft(1)=-1 and IX>0 : ADD IX,-SCRLLSP : End If
Loop