'===========================================================================
' Subject: BOUNCING/ROTATING TRIANGLE        Date: 04-30-96 (06:30)       
' Author:  Cam Spowart                       Code: QB, QBasic, PDS        
' Origin:  slyboots@supernet.ab.ca         Packet: GRAPHICS.ABC
'===========================================================================
DECLARE SUB grid ()
timesvar = 1.5
beg:
CLS
RANDOMIZE TIMER
xinc = .1
RANDOMIZE TIMER
yinc = .1
RANDOMIZE TIMER
neg = INT(RND * 2)
RANDOMIZE TIMER
neg1 = INT(RND * 2)

IF neg = 0 THEN xinc = xinc
IF neg = 1 THEN xinc = xinc * -1
IF neg1 = 0 THEN yinc = yinc
IF neg1 = 1 THEN yinc = yinc * -1

SCREEN 12

RANDOMIZE TIMER
xcoor = RND * 640
RANDOMIZE TIMER
yCoor = RND * 480
x1Coor = xcoor + 100
y1Coor = yCoor
x2Coor = xcoor + 50
y2Coor = yCoor - 74


DO

 grid

 KEY(1) ON
 KEY(10) ON
 ON KEY(1) GOSUB revamp
 ON KEY(10) GOSUB show
 LINE (xOld, yOld)-(x1Old, y1Old), 0
 LINE (x1Old, y1Old)-(x2Old, y2Old), 0
 LINE (x2Old, y2Old)-(xOld, yOld), 0

 xcoor = xcoor + xinc
 yCoor = yCoor + yinc
 x1Coor = x1Coor + xinc
 y1Coor = y1Coor + timesvar * yinc
 x2Coor = x2Coor + timesvar * xinc
 y2Coor = y2Coor + timesvar * yinc
 clr = INT(RND * 15) + 1
 LINE (xcoor, yCoor)-(x1Coor, y1Coor), clr
 LINE (x1Coor, y1Coor)-(x2Coor, y2Coor), clr
 LINE (x2Coor, y2Coor)-(xcoor, yCoor), clr
 
 xOld = xcoor
 x1Old = x1Coor
 x2Old = x2Coor
 yOld = yCoor
 y1Old = y1Coor
 y2Old = y2Coor

 IF xcoor > 720 OR xcoor < 0 THEN GOSUB changex
 IF yCoor > 348 OR yCoor < 0 THEN GOSUB changey

getback:

LOOP UNTIL INKEY$ = " "

CLS
END

changex:
xinc = xinc * -1
RETURN getback

changey:
yinc = yinc * -1
RETURN getback

revamp:
CLS
GOTO beg

show:
LOCATE 11, 10: PRINT "Bouncing, moving, rotating, blinking triangles 
(tm)"
LOCATE 12, 25: PRINT "by Cam Spowart (1995)"
LOCATE 13, 15: PRINT "Hit space to exit, F1 to redraw, and F10 to see 
this"
DO WHILE INKEY$ = "": LOOP
GOTO beg

SUB grid

xcircle = RND * 640
ycircle = RND * 480
radius = RND * 20
seveneightnine = 7
PSET (xcircle, ycircle), seveneightnine
'CIRCLE (xcircle, ycircle), radius, clr

'FOR xJump = 0 TO 640 STEP 64
'clr = 4
'LINE (xJump, 0)-(xJump, 480), clr
'NEXT xJump

'FOR yJump = 0 TO 480 STEP 64
'clr = 4
'LINE (0, yJump)-(640, yJump), clr
'NEXT yJump

END SUB