This is a short game by Endi Baráth, originally published on the BASIC Programming Language group. It was converted to ugBASIC by Marco Spedaletti, to work on most 8-bit computers. It needs at least the 1.6.2-beta to compile. A reference to the original source has been added as comment.

 
 ' It is necessary to apply some techniques to reduce the memory actually 
 ' used, so that the game can run even on rather limited platforms, 
 ' such as ColecoVision.
 
 ' First, let's proceed to reduce the space occupied by dynamic strings. 
 ' In ugBASIC this space, despite being dynamic, is statically allocated 
 ' and occupies a certain memory space. With those pragmas we tell ugBASIC 
 ' that we will never use more than 8 strings by a total of 32 bytes. 
 ' Static strings, such as those in quotes, don't count.
 
 DEFINE STRING SPACE 32
 DEFINE STRING COUNT 8
 
 ' This procedure reads the fire button if a joystick is available.
 
 PROCEDURE control ON JOYSTICK AVAILABLE
 	IF JFIRE(0) THEN
 		RETURN TRUE		
 	ELSE
 		RETURN FALSE
 	ENDIF
 END PROC
 
 ' This procedure reads the space bar if a joystick is not available.
 
 PROCEDURE control ON JOYSTICK NOT AVAILABLE
 	IF KEY STATE(KEY SPACE) THEN
 		RETURN TRUE		
 	ELSE
 		RETURN FALSE
 	ENDIF
 END PROC
 
 ' ------------------------------------------------------------------
 ' 100 GRAPHICS HIRES 4:SET BORDER 0:SET KEY CLICK OFF:SET STATUS OFF
 ' ------------------------------------------------------------------
 
 ' We enable the "bitmap" graphics mode. This is the mode in which 
 ' each individual pixel can be addressed individually, via primitive 
 ' commands, such as those related to drawing a single pixel.
 
 BITMAP ENABLE
 
 ' With this instruction we clear the screen, using (if possible) the color 
 ' black. Remembering that ugBASIC is an isomorphic language, it is possible 
 ' that the color indication is ignored, or a similar one is chosen.
 
 CLS BLACK
 
 ' We set the border color to black, at least for those targets for 
 ' which this instruction makes sense. Since ugBASIC is an isomorphic 
 ' language, it does not provide an abstraction of the concept of 
 ' "border". Therefore, if the border exists, it will be colored, 
 ' otherwise this statement corresponds to a "no operation".
 
 COLOR BORDER BLACK
 
 ' Let's define the (pixel) coordinates of the play field:
 '
 '    (x1,y1) +---------+
 '            |         |
 '            |         |
 '            +---------+ (x2,y2)
 
 POSITIVE CONST x1 = SCREEN WIDTH / 10 
 POSITIVE CONST x2 = x1 + (8 * ( SCREEN WIDTH / 10 ))
 POSITIVE CONST y1 = SCREEN HEIGHT / 10 
 POSITIVE CONST y2 = y1 + (7 * ( SCREEN HEIGHT / 10 ))
 
 ' Let's define the (characters) coordinates of the play field:
 '
 '  (,r1) --> INSTRUCTIONS
 '            +---------+
 '            |         |
 '            |         |
 '            +---------+
 '    (,r2) --> COMMAND
 
 POSITIVE CONST r1 = 0
 POSITIVE CONST r2 = ROWS-2
 
 ' Instructions string. The lenght of this string depends on
 ' the width of the text screen.
 
 CONST instructions = IF(COLUMNS < 40, "press to turn", "GAME: press to turn direction")
 CONST final = IF(COLUMNS < 40, "SCORE: ", "YOUR SCORE: ")
 
 ' Let's memorize the status of fire and the previous state itself.
 ' This allow to track the fact that the fire has been released.
 
 joy = FALSE: joyp = FALSE
 
 ' ----------------------------------------------------------
 ' 110 SET INK 2:PLOT 500,200;800,200;800,500;500,500;500,200
 ' ----------------------------------------------------------
 
 ' Let's draw the yellow box as playfield.
 
 BOX x1,y1 TO x2,y2,YELLOW
 
 ' ------------------------------------------------------------
 ' 120 PRINT #101,AT 2,2:"GAME: press a key to turn direction."
 ' ------------------------------------------------------------
 
 ' Let's print the intructions at the center of the line.
 
 LOCATE ,r1
 CENTER instructions;
 
 ' -------------------------------------------------
 ' 130 SET INK 3:LET I=0:LET X=550:LET Y=220:LET S=0
 ' -------------------------------------------------
 
 i = 0
 x = x1+x1
 y = y1+y1
 s = 0
 
 '            +---------+
 '            | * (x,y) |
 '            |         |
 '            +---------+
 
 ' Forever loop until finish.
 
 DO
 
 ' ---------------------------
 ' 140 LET I$=INKEY$:LET S=S+1
 ' ---------------------------
 
 	' Slow down the program a bit, to make it playable.
 	
 	WAIT 25 MS
 
 	' Let's record if the button has been pressed AND released.
 
 	IF joy THEN
 		IF control[] = 0 THEN
 			joyp = TRUE
 			joy = FALSE
 		ENDIF
 	ELSE
 		joy = control[]
 	ENDIF
 	
 	' Increment the score!
 	
 	INC s
 
 	' -------------
 	' 150 PLOT X,Y,
 	' 160 LOOK A
 	' -------------
 	
 	' Take the color of destination pixel.
 	
 	a = POINT(x,y)
 
 	' Draw a pixel on it.
 	
 	PLOT x,y,WHITE
 
 	' ---------------------------------------
 	' 170 PLOT X,Y
 	' 180 IF I$ ≠ "" THEN LET I= (I+1) BAND 3
 	' ---------------------------------------
 	
 	' Each time the fire / space bar is pressed, the
 	' direction will be changed, in a clockwise manner.
 	' The (i+1) increment the direction, while the AND
 	' 3 will limit the value from 0 to 3.
 	'
 	'             3
 	'             ^
 	'         2 <-+-> 0
 	'             v
 	'             1
 	
 	IF joyp THEN i = (i+1) AND 3
 
 	' Reset the button.
 	
 	joyp = FALSE
 
 	' -----------------------------------
 	' 190 IF I=0 THEN LET X=X+4:LET Y=Y+0
 	' -----------------------------------
 	
 	' Move the point to the right.
 	
 	IF i=0 THEN INC x
 
 	' -----------------------------------
 	' 200 IF I=1 THEN LET X=X+0:LET Y=Y+4
 	' -----------------------------------
 
 	' Move the point down.
 	
 	IF i=1 THEN INC y
 
 	' -----------------------------------
 	' 210 IF I=2 THEN LET X=X-4:LET Y=Y+0
 	' -----------------------------------
 
 	' Move the point to the left.
 
 	IF i=2 THEN DEC x
 
 	' -----------------------------------
 	' 220 IF I=3 THEN LET X=X+0:LET Y=Y-4
 	' -----------------------------------
 
 	' Move the point to the right.
 	
 	IF i=3 THEN DEC y
 
 	' ------------------------
 	' 230 IF A=0 THEN GOTO 140
 	' ------------------------
 
 	' If the underlying pixel is black, we can move
 	' to the next position along the selected direction.
 	' Oherwise, we can exit.
 	
 	EXIT IF a<>BLACK
 
 LOOP
 
 ' ---------------------------------------
 ' 240 PRINT #101,AT 19,12:"YOUR SCORE:";S
 ' ---------------------------------------
 
 ' Print the score and ends.
 
 LOCATE , r2
 CENTER final+STR$(s);
 
 

• game.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 game.bas -o example.xex
 altirra example.xex
 
 # Windows 
 ugbc.atari.exe game.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 game.bas -o example.xex
 altirra example.xex
 
 # Windows 
 ugbc.atarixl.exe game.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 game.bas -o example.prg
 x64sc example.prg
 
 # Windows 
 ugbc.c64.exe game.bas -o example.prg
 x64sc example.prg

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.c64reu game.bas -o example.prg
 x64sc -reu example.prg
 
 # Windows 
 ugbc.c64reu.exe game.bas -o example.prg
 x64sc -reu 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 game.bas -o example.prg
 yape example.prg
 
 # Windows 
 ugbc.plus4.exe game.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 game.bas -o example.prg
 xplus4 example.prg
 
 # Windows 
 ugbc.plus4.exe game.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 game.bas -o example.bin
 xroar -rompath (your rom path) example.bin
 
 # Windows 
 ugbc.d32.exe game.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 game.bas -o example.bin
 xroar -rompath (your rom path) example.bin
 
 # Windows 
 ugbc.d64.exe game.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 game.bas -o example.k7
 dcmoto
 (choose BASIC 128)
 CLEAR,&H2FFF: LOADM"CASS:",R: EXEC
 
 # Windows 
 ugbc.pc128op.exe game.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 game.bas -o example.k7
 dcmoto
 (choose BASIC 128)
 CLEAR,&H2FFF: LOADM"CASS:",R: EXEC
 
 # Windows 
 ugbc.pc128op.exe game.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 game.bas -o example.prg
 xvic --memory 24k example.prg
 
 # Windows 
 ugbc.vic20.exe game.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 game.bas -o example.tap
 Speccy example.tap
 
 # Windows 
 ugbc.zx.exe game.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 game.bas -o example.rom
 openmsx -cart example.rom
 
 # Windows 
 ugbc.msx1.exe game.bas -o example.rom
 openmsx -cart example.rom

 # Linux 
 ugbc.msx1 game.bas -o example.rom
 bluemsx example.rom
 
 # Windows 
 ugbc.msx1.exe game.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 game.bas -o example.rom
 openmsx -machine \"COL - ColecoVision\" -cart example.rom
 
 # Windows 
 ugbc.coleco.exe game.bas -o example.rom
 bluemsx -machine \"COL - ColecoVision\" example.rom

 # Linux 
 ugbc.coleco game.bas -o example.rom
 bluemsx /machine \"COL - ColecoVision\" /rom1 example.rom
 
 # Windows 
 ugbc.coleco.exe game.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 game.bas -o example.rom
 bluemsx /machine \"SEGA - SC-3000\" /rom1 example.rom
 
 # Windows 
 ugbc.sc3000.exe game.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 game.bas -o example.rom
 bluemsx /machine \"SEGA - SG-1000\" /rom1 example.rom
 
 # Windows 
 ugbc.sg1000.exe game.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!