'===========================================================================
' Subject: COLORFUL BOUNCING LINES           Date: 12-20-97 (10:33)       
' Author:  Alexander Meyer                   Code: QB, QBasic, PDS        
' Origin:  Meyer.Karl@t-online.de          Packet: GRAPHICS.ABC
'===========================================================================
'                             ////
'                           0(o o)0
'-------------------------ooO (_) Ooo---------------------
' LINEBOUN.BAS -- Written in QuickBasic 4.5
'           
' Name: Colourful bouning lines
' Author: Alexander Meyer
' Date: 11-23-1997
' Description: This shows four bouncing lines in VGA
'
'For questions or comments mail to: Meyer.Karl@t-online.de
'-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
SCREEN 13                 'VGA 320 x 200

DIM x(1 TO 4)
DIM y(1 TO 4)
DIM XDir(1 TO 4)
DIM YDir(1 TO 4)

x(1) = 0: y(1) = 0
x(2) = 319: y(2) = 199
x(3) = 0: y(3) = 199
x(4) = 319: y(4) = 0

DO

FOR a = 1 TO 4     'For all four lines

IF x(a) >= 319 THEN XDir(a) = 1
IF x(a) <= 1 THEN XDir(a) = 0
IF y(a) >= 199 THEN YDir(a) = 1
IF y(a) <= 1 THEN YDir(a) = 0

IF XDir(a) = 0 THEN
  x(a) = x(a) + 1
ELSE
  x(a) = x(a) - 1
END IF
IF YDir(a) = 0 THEN
  y(a) = y(a) + 1
ELSE
  y(a) = y(a) - 1
END IF

NEXT a

c = c + 1
IF c = 248 THEN c = 1
IF INKEY$ <> "" THEN END
PSET (x(1), y(1)), c          'Draw lines
PSET (x(2), y(2)), c
PSET (x(3), y(3)), c
PSET (x(4), y(4)), c

LOOP

END