'===========================================================================
' Subject: STAR FIELD 3D                     Date: 01-07-98 (19:26)       
' Author:  Nick Kochakian                    Code: QB, QBasic, PDS        
' Origin:  NickK@worldnet.att.net          Packet: GRAPHICS.ABC
'===========================================================================
DECLARE SUB draw.stars ()
'Star Field 3D
'
'verison 1.0
'
'This is my first GOOD and FAST 3D star field. (Compared to SField.bas)
'Please adjust the settings before running the program.
'
'This program currently has 3 layers of stars. But that's going to change
'to 3 to 10 layers by Star Field 3D ver. 2.0
'
'(If you didn't change the settings yet they are currently set for:
'a P60... Look at the chart below...)
'
'High res mode looks impressive with 500 stars. :)
'
'Have fun!

DEFINT A-Z
RANDOMIZE TIMER

'Computer speed chart: (values recommended for best performance)
'286, 386 -> stars = 50 to 150, res low
'486      -> stars = 100 to 200
'Pentium  -> stars = 100 to 500

res$ = "low"
'res$ values:
'low
'high

video$ = "vga"
'video$ values:
'vga


IF res$ = "low" AND video$ = "vga" THEN scr.mode = 13: GOTO ok.ok:
IF res$ = "high" AND video$ = "vga" THEN scr.mode = 12: GOTO ok.ok:

PRINT "That's not a valid configuration!": END

ok.ok:
SCREEN scr.mode

DIM SHARED stars
stars = 500
DIM SHARED x(stars)
DIM SHARED y(stars)
DIM SHARED z(stars)
DIM SHARED c(stars)

'z ===>  1   -   2   -   3
'        far  --------- near

FOR i = 1 TO stars

IF scr.mode = 13 THEN
x(i) = INT(RND * 320) + 1
y(i) = INT(RND * 200) + 1
z(i) = INT(RND * 3) + 1
END IF

IF scr.mode = 13 THEN
IF z(i) = 1 THEN c(i) = 20
IF z(i) = 2 THEN c(i) = 25
IF z(i) = 3 THEN c(i) = 30
END IF

IF scr.mode = 12 THEN
x(i) = INT(RND * 640) + 1
y(i) = INT(RND * 480) + 1
z(i) = INT(RND * 3) + 1
END IF

IF scr.mode = 12 THEN
IF z(i) = 1 THEN c(i) = 8
IF z(i) = 2 THEN c(i) = 7
IF z(i) = 3 THEN c(i) = 15
END IF

NEXT i

draw.stars

i = 1

move$ = "<"

DO

PSET (x(i), y(i)), 0

IF move$ = "<" THEN
IF z(i) = 1 THEN x(i) = x(i) - .7
IF z(i) = 2 THEN x(i) = x(i) - 1.5
IF z(i) = 3 THEN x(i) = x(i) - 3
END IF

PSET (x(i), y(i)), c(i)

'FOR a = 1 TO 999
'NEXT a

IF x(i) < 0 THEN GOSUB re.rand.star:
i = i + 1
IF i > stars THEN i = 1
LOOP UNTIL INKEY$ <> ""

END

re.rand.star:

IF scr.mode = 13 THEN
x(i) = 320
y(i) = INT(RND * 200) + 1
z(i) = INT(RND * 3) + 1
IF z(i) = 1 THEN c(i) = 20
IF z(i) = 2 THEN c(i) = 25
IF z(i) = 3 THEN c(i) = 30
END IF

IF scr.mode = 12 THEN
x(i) = 640
y(i) = INT(RND * 480) + 1
z(i) = INT(RND * 3) + 1
IF z(i) = 1 THEN c(i) = 8
IF z(i) = 2 THEN c(i) = 7
IF z(i) = 3 THEN c(i) = 15
END IF

RETURN

SUB draw.stars

FOR i = 1 TO stars
PSET (x(i), y(i)), c(i)
NEXT i

END SUB