INK BROWN
 CLS
 COLOR BORDER LIGHT BLUE
 
 CONST POSITIVE maxWalls = 3
 CONST POSITIVE windowHeight = 3
 CONST POSITIVE maxPlayers = 2
 
 basement = LOAD TILES("examples/scrolling_basement.png") TRANSPARENT 
 
 DIM wall AS TILES(maxWalls)
 wall(0) = LOAD TILES("examples/scrolling_wall0.png") TRANSPARENT
 wall(1) = LOAD TILES("examples/scrolling_wall1.png") TRANSPARENT
 wall(2) = LOAD TILES("examples/scrolling_wall2.png") TRANSPARENT
 
 DIM window AS TILES(windowHeight)
 window(0) = LOAD TILES("examples/scrolling_window0.png") TRANSPARENT
 window(1) = LOAD TILES("examples/scrolling_window1.png") TRANSPARENT
 window(2) = LOAD TILES("examples/scrolling_window2.png") TRANSPARENT
 
 DIM player AS SPRITE(maxPlayers)
 player(0) = CSPRITE(LOAD IMAGE("examples/scrolling_player0.png"))
 player(1) = CSPRITE(LOAD IMAGE("examples/scrolling_player1.png"))
 
 arrow = SPRITE(LOAD IMAGE("examples/scrolling_arrow.png"))
 
 rowIndex = 0
 windowIndex = 0
 playerIndex = 0
 playerX = ( SCREEN WIDTH - SPRITE WIDTH ) \ #2
 arrowX = 0
 arrowY = 0
 
 GLOBAL wall
 GLOBAL window
 GLOBAL rowIndex
 GLOBAL windowIndex
 GLOBAL playerIndex
 GLOBAL playerX
 GLOBAL arrowX
 GLOBAL arrowY
 
 SCREEN ROWS 24
 
 SCROLL LEFT
 SCROLL LEFT
 SCROLL LEFT
 SCROLL LEFT
 
 DRAW TILES basement ROW 0, 0 TO SCREEN TILES WIDTH - 1
 
 DOUBLE BUFFER ON
 
 BEGIN GAMELOOP
 
     PROCEDURE refreshRow
 
         x = (BYTE) 0
 
         IF rowIndex > 0 THEN
             DRAW TILES wall(rowIndex) ROW 0, 0 TO rowIndex - 1
         ENDIF
 
         DRAW TILES wall(rowIndex) ROW 0, rowIndex TO SCREEN TILES WIDTH - 1
 
         IF windowIndex > 4 THEN
             w = TILES WIDTH(window(windowIndex-5))
             x = 4
             DRAW TILES window(windowIndex-5) ROW 0, x TO x + w - 1
             ADD x, w ** #2
             DRAW TILES window(windowIndex-5) ROW 0, x TO x + w - 1
             ADD x, w ** #2
             DRAW TILES window(windowIndex-5) ROW 0, x TO x + w - 1
         ENDIF
 
         SPRITE player(playerIndex) AT playerX, SCREEN HEIGHT - SPRITE HEIGHT - TILES HEIGHT(basement) ENABLE
         SPRITE player(1-playerIndex) DISABLE
         
         ADD rowIndex, 1, 0 TO 2
         ADD windowIndex, 1, 0 TO 7
         ADD playerIndex, 1, 0 TO 1
 
     END PROC
 
     ON SCROLL DOWN ROW CALL refreshRow
 
     SCROLL DOWN
 
     SELECT CASE JOY(0)
         CASE JOY LEFT
             IF playerX > 0 THEN
                 DEC playerX
             ENDIF
         CASE JOY RIGHT
             IF playerX < (SCREEN WIDTH - SPRITE WIDTH)  THEN
                 INC playerX
             ENDIF
     ENDSELECT
 
     IF RND(100) > 50 THEN
         IF arrowY = 0 THEN
             arrowX = RND(SCREEN WIDTH - SPRITE WIDTH - 1)
             arrowY = 1
         ENDIF
     ENDIF
 
     IF arrowY > 0 THEN
         ADD arrowY, 3, 0 TO SCREEN HEIGHT + SPRITE HEIGHT
         SPRITE arrow AT arrowX, arrowY ENABLE
     ELSE
         SPRITE arrow DISABLE
     ENDIF
 
 END GAMELOOP
 

• scrolling_example_04.bas

The instructions here refer to compiling the example from the command line. For Microsoft Windows users we suggest using UGBASIC-IDE, which allows you to compile the example with just one click.

In order to compile and run the example, you need to have the Altirra emulator, and in particular that the altirra executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.atari scrolling_example_04.bas -o example.xex
 altirra example.xex
 
 # Windows 
 ugbc.atari.exe scrolling_example_04.bas -o example.xex
 altirra example.xex

In order to compile and run the example, you need to have the Altirra emulator, and in particular that the altirra executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.atarixl scrolling_example_04.bas -o example.xex
 altirra example.xex
 
 # Windows 
 ugbc.atarixl.exe scrolling_example_04.bas -o example.xex
 altirra example.xex

In order to compile and run the example, you need to have the VICE emulator, and in particular that the x64sc executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.c64 scrolling_example_04.bas -o example.prg
 x64sc example.prg
 
 # Windows 
 ugbc.c64.exe scrolling_example_04.bas -o example.prg
 x64sc example.prg

In order to run the example, you need to have the YAPE emulator. In particular that the yape executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.plus4 scrolling_example_04.bas -o example.prg
 yape example.prg
 
 # Windows 
 ugbc.plus4.exe scrolling_example_04.bas -o example.prg
 yape example.prg

In order to run the example, you need to have the VICE emulator. In particular that the xplus4 executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.plus4 scrolling_example_04.bas -o example.prg
 xplus4 example.prg
 
 # Windows 
 ugbc.plus4.exe scrolling_example_04.bas -o example.prg
 xplus4 example.prg

In order to compile and run the example, you need to have the XROAR emulator, and in particular that the xroar executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.d32 scrolling_example_04.bas -o example.bin
 xroar -rompath (your rom path) example.bin
 
 # Windows 
 ugbc.d32.exe scrolling_example_04.bas -o example.bin
 xroar.exe -rompath (your rom path) example.bin

In order to compile and run the example, you need to have the XROAR emulator, and in particular that the xroar executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.d64 scrolling_example_04.bas -o example.bin
 xroar -rompath (your rom path) example.bin
 
 # Windows 
 ugbc.d64.exe scrolling_example_04.bas -o example.bin
 xroar.exe -rompath (your rom path) example.bin

In order to compile and run the example, you need to have the DCMOTO emulator, and in particular that the dcmoto executable is accessible.

Then, type this command on the command line and on the emulator:

 # Linux 
 ugbc.pc128op scrolling_example_04.bas -o example.k7
 dcmoto
 (choose BASIC 128)
 CLEAR,&H2FFF: LOADM"CASS:",R: EXEC
 
 # Windows 
 ugbc.pc128op.exe scrolling_example_04.bas -o example.k7
 dcmoto
 (choose example.k7)
 (choose BASIC 128)
 CLEAR,&H2FFF: LOADM"CASS:",R: EXEC

In order to compile and run the example, you need to have the DCMOTO emulator, and in particular that the dcmoto executable is accessible.

Then, type this command on the command line and on the emulator:

 # Linux 
 ugbc.pc128op scrolling_example_04.bas -o example.k7
 dcmoto
 (choose BASIC 128)
 CLEAR,&H2FFF: LOADM"CASS:",R: EXEC
 
 # Windows 
 ugbc.pc128op.exe scrolling_example_04.bas -o example.k7
 dcmoto
 (choose example.k7)
 (choose BASIC 128)
 CLEAR,&H2FFF: LOADM"CASS:",R: EXEC

In order to compile and run the example, you need to have the VICE emulator, and in particular that the xvic executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.vic20 scrolling_example_04.bas -o example.prg
 xvic --memory 24k example.prg
 
 # Windows 
 ugbc.vic20.exe scrolling_example_04.bas -o example.prg
 xvic --memory 24k example.prg

In order to compile and run the example, you need to have the Speccy emulator, and in particular that the speccy executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.zx scrolling_example_04.bas -o example.tap
 Speccy example.tap
 
 # Windows 
 ugbc.zx.exe scrolling_example_04.bas -o example.tap
 Speccy example.tap

In order to compile and run the example, you need to have the openMsx or the BlueMSX emulator, and in particular that its executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.msx1 scrolling_example_04.bas -o example.rom
 openmsx -cart example.rom
 
 # Windows 
 ugbc.msx1.exe scrolling_example_04.bas -o example.rom
 openmsx -cart example.rom

 # Linux 
 ugbc.msx1 scrolling_example_04.bas -o example.rom
 bluemsx example.rom
 
 # Windows 
 ugbc.msx1.exe scrolling_example_04.bas -o example.rom
 bluemsx example.rom

In order to compile and run the example, you need to have the openMsx or the BlueMSX emulator, and in particular that its executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.coleco scrolling_example_04.bas -o example.rom
 openmsx -machine \"COL - ColecoVision\" -cart example.rom
 
 # Windows 
 ugbc.coleco.exe scrolling_example_04.bas -o example.rom
 bluemsx -machine \"COL - ColecoVision\" example.rom

 # Linux 
 ugbc.coleco scrolling_example_04.bas -o example.rom
 bluemsx /machine \"COL - ColecoVision\" /rom1 example.rom
 
 # Windows 
 ugbc.coleco.exe scrolling_example_04.bas -o example.rom
 bluemsx  /machine \"COL - ColecoVision\" /rom1 example.rom

In order to compile and run the example, you need to have the BlueMSX emulator, and in particular that its executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.sc3000 scrolling_example_04.bas -o example.rom
 bluemsx /machine \"SEGA - SC-3000\" /rom1 example.rom
 
 # Windows 
 ugbc.sc3000.exe scrolling_example_04.bas -o example.rom
 bluemsx  /machine \"SEGA - SC-3000\" /rom1 example.rom

In order to compile and run the example, you need to have the BlueMSX emulator, and in particular that its executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.sg1000 scrolling_example_04.bas -o example.rom
 bluemsx /machine \"SEGA - SG-1000\" /rom1 example.rom
 
 # Windows 
 ugbc.sg1000.exe scrolling_example_04.bas -o example.rom
 bluemsx  /machine \"SEGA - SG-1000\" /rom1 example.rom

If you have found a problem trying to run this example, if you think there is a bug or, more simply, you would like it to be improved, open an issue for this example on GitHub. Thank you!