{{htmlmetatags>metatag-robots=()
metatag-title=(OTHER CONTRIBUTIONS STAFIELD | ugBASIC User Manual)
metatag-keywords=(ugBASIC,Commodore 64,Commodore PLUS/4,ZX Spectrum)
metatag-description=(An isomorphic language for retrocomputers)
metatag-media-og:image=(:ugbasic:logo-ugbasic-fb.png)
metatag-og:title=(OTHER CONTRIBUTIONS STAFIELD | ugBASIC User Manual) 
metatag-og:description=(An isomorphic language for retrocomputers)
}}

====== ugBASIC User Manual ======

===== OTHER CONTRIBUTIONS STAFIELD =====

==== PURPOSE ====
 This example shows a simple starfield by S.Devulder for ugBasic. Modified by M.Spedaletti.  

==== SOURCE CODE ====
   
   
   CONST numr  =  1000 : REM num of random position in pool 
   CONST nums  =    20 : REM number of stars in starfield
   CONST speed =     8 : REM speed of stars (smaller = faster)
   CONST clock =    50 : REM Number of TI per second
   CONST bg    = BLACK : REM background color
   CONST fg    = WHITE : REM forteground color
   
   DIM xrnd AS POSITION (numr+1)
   DIM yrnd AS POSITION (numr+1)
   
   DIM xtab AS POSITION (nums+1)
   DIM ytab AS POSITION (nums+1)
   
   BITMAP ENABLE (320,200,2)
   CLS bg
   COLOR BORDER bg 
   
   FOR i=0 TO numr
   	xrnd(i) = RND(SCREEN WIDTH)
   	yrnd(i) = RND(SCREEN HEIGHT)
   NEXT
   irnd = 0
   
   FOR i=0 TO nums
   	' REPEAT : c = RND(SCREEN COLORS) : UNTIL c<>bg
   	xtab(i) = RND(SCREEN WIDTH)
   	ytab(i) = RND(SCREEN HEIGHT) 
   	
   	PLOT xtab(i),ytab(i),fg
   NEXT
   
   VAR x0 AS SIGNED WORD = (SCREEN WIDTH / 2)
   VAR y0 AS SIGNED WORD = (SCREEN HEIGHT / 2)
   
   VAR x AS SIGNED WORD = 0
   VAR y AS SIGNED WORD = 0
   VAR z AS SIGNED WORD = 0
   VAR t AS SIGNED WORD = 0
   VAR dx AS SIGNED WORD = 0
   VAR dy AS SIGNED WORD = 0
   
   TI=0: frames = 0
   DO
   	INC frames
   	PLOT x0,y0,WHITE
   	IF TI>=clock THEN 
   		LOCATE 0,0 : PRINT frames;"    ";
   		frames = 0 
   		TI = 0
   	ENDIF
   	FOR i=0 TO nums
   		z = xtab(i)
   		x = z + (z - x0)/speed
   
   		t = ytab(i)	
   		y = t + (t - y0)/speed
   		
   		IF (((x OR y)<0) OR (y>=SCREEN HEIGHT)) OR (x>=SCREEN WIDTH) THEN
   			REPEAT
   				x = xrnd(irnd)
   				y = yrnd(irnd)
   				ADD irnd,1,0 TO numr
   			UNTIL ((x-x0)/speed) AND ((y-y0)/speed)
   		ENDIF
   		
   		xtab(i) = x
   		ytab(i) = y
   		
   		PLOT z,t,bg
   		PLOT x,y,fg
   		'PLOT x,y,bg
   	NEXT
       WAIT VBL
   	joy = JOY(0) : dx = 0 : dy = 0
   	IF joy HAS BIT LEFT  THEN : DEC dx : ENDIF
   	IF joy HAS BIT RIGHT THEN : INC dx : ENDIF
   	IF joy HAS BIT UP    THEN : DEC dy : ENDIF
   	IF joy HAS BIT DOWN  THEN : INC dy : ENDIF
   	IF (dx OR dy)<>0 THEN
   		IF joy HAS BIT FIRE THEN : MUL dx,4 : MUL dy,4 : ENDIF
   		PLOT x0,y0,bg
   		ADD x0,dx,0 TO SCREEN WIDTH
   		ADD y0,dy,0 TO SCREEN HEIGHT
   	ENDIF
   LOOP
   


==== SOURCE FILE ====
  * ''[[https://github.com/spotlessmind1975/ugbasic/tree/main/examples/contrib_starfield.bas|contrib_starfield.bas]]''
==== HOW TO COMPILE AND RUN ====
The instructions here refer to compiling the example from the command line. For Microsoft Windows users we suggest using **[[https://spotlessmind1975.itch.io/ugbasic-ide|UGBASIC-IDE]]**, which allows you to compile the example with just one click.=== ATARI 400/800 family ===
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 contrib_starfield.bas -o example.xex
   altirra example.xex
   
   # Windows 
   ugbc.atari.exe contrib_starfield.bas -o example.xex
   altirra example.xex
=== ATARI 600XL/800XL/1200XL/XG(SE) family ===
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 contrib_starfield.bas -o example.xex
   altirra example.xex
   
   # Windows 
   ugbc.atarixl.exe contrib_starfield.bas -o example.xex
   altirra example.xex
=== Commodore 64 ===
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 contrib_starfield.bas -o example.prg
   x64sc example.prg
   
   # Windows 
   ugbc.c64.exe contrib_starfield.bas -o example.prg
   x64sc example.prg
=== Commodore 64+REU ===
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 contrib_starfield.bas -o example.prg
   x64sc -reu example.prg
   
   # Windows 
   ugbc.c64reu.exe contrib_starfield.bas -o example.prg
   x64sc -reu example.prg
=== Commodore PLUS/4 ===
== Using YAPE ==
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 contrib_starfield.bas -o example.prg
   yape example.prg
   
   # Windows 
   ugbc.plus4.exe contrib_starfield.bas -o example.prg
   yape example.prg
== Using VICE ==
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 contrib_starfield.bas -o example.prg
   xplus4 example.prg
   
   # Windows 
   ugbc.plus4.exe contrib_starfield.bas -o example.prg
   xplus4 example.prg
=== Dragon 32 ===
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 contrib_starfield.bas -o example.bin
   xroar -rompath (your rom path) example.bin
   
   # Windows 
   ugbc.d32.exe contrib_starfield.bas -o example.bin
   xroar.exe -rompath (your rom path) example.bin
=== Dragon 64 ===
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 contrib_starfield.bas -o example.bin
   xroar -rompath (your rom path) example.bin
   
   # Windows 
   ugbc.d64.exe contrib_starfield.bas -o example.bin
   xroar.exe -rompath (your rom path) example.bin
=== PC128 Olivetti Prodest ===
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 contrib_starfield.bas -o example.k7
   dcmoto
   (choose BASIC 128)
   CLEAR,&H2FFF: LOADM"CASS:",R: EXEC
   
   # Windows 
   ugbc.pc128op.exe contrib_starfield.bas -o example.k7
   dcmoto
   (choose example.k7)
   (choose BASIC 128)
   CLEAR,&H2FFF: LOADM"CASS:",R: EXEC
=== Thomson MO5 ===
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 contrib_starfield.bas -o example.k7
   dcmoto
   (choose BASIC 128)
   CLEAR,&H2FFF: LOADM"CASS:",R: EXEC
   
   # Windows 
   ugbc.pc128op.exe contrib_starfield.bas -o example.k7
   dcmoto
   (choose example.k7)
   (choose BASIC 128)
   CLEAR,&H2FFF: LOADM"CASS:",R: EXEC
=== Commodore VIC-20 ===
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 contrib_starfield.bas -o example.prg
   xvic --memory 24k example.prg
   
   # Windows 
   ugbc.vic20.exe contrib_starfield.bas -o example.prg
   xvic --memory 24k example.prg
=== ZX Spectrum ===
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 contrib_starfield.bas -o example.tap
   Speccy example.tap
   
   # Windows 
   ugbc.zx.exe contrib_starfield.bas -o example.tap
   Speccy example.tap
=== MSX ===
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:

== openMSX ==
   # Linux 
   ugbc.msx1 contrib_starfield.bas -o example.rom
   openmsx -cart example.rom
   
   # Windows 
   ugbc.msx1.exe contrib_starfield.bas -o example.rom
   openmsx -cart example.rom
== blueMSX ==
   # Linux 
   ugbc.msx1 contrib_starfield.bas -o example.rom
   bluemsx example.rom
   
   # Windows 
   ugbc.msx1.exe contrib_starfield.bas -o example.rom
   bluemsx example.rom
=== ColecoVision ===
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:

== openMSX ==
   # Linux 
   ugbc.coleco contrib_starfield.bas -o example.rom
   openmsx -machine \"COL - ColecoVision\" -cart example.rom
   
   # Windows 
   ugbc.coleco.exe contrib_starfield.bas -o example.rom
   bluemsx -machine \"COL - ColecoVision\" example.rom
== blueMSX ==
   # Linux 
   ugbc.coleco contrib_starfield.bas -o example.rom
   bluemsx /machine \"COL - ColecoVision\" /rom1 example.rom
   
   # Windows 
   ugbc.coleco.exe contrib_starfield.bas -o example.rom
   bluemsx  /machine \"COL - ColecoVision\" /rom1 example.rom
=== SEGA SC-3000 ===
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 contrib_starfield.bas -o example.rom
   bluemsx /machine \"SEGA - SC-3000\" /rom1 example.rom
   
   # Windows 
   ugbc.sc3000.exe contrib_starfield.bas -o example.rom
   bluemsx  /machine \"SEGA - SC-3000\" /rom1 example.rom
=== SEGA SG-1000 ===
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 contrib_starfield.bas -o example.rom
   bluemsx /machine \"SEGA - SG-1000\" /rom1 example.rom
   
   # Windows 
   ugbc.sg1000.exe contrib_starfield.bas -o example.rom
   bluemsx  /machine \"SEGA - SG-1000\" /rom1 example.rom
==== ANY PROBLEM? ====
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, [[https://github.com/spotlessmind1975/ugbasic/issues/new?title=IMPROVE OTHER CONTRIBUTIONS STAFIELD|open an issue]] for this example on GitHub. Thank you!===== POWERED BY =====

[[:ugbasic:user:examples|{{ :ugbasic:user:logo-ugbasic.png?nolink&600 |}}]]