;
; test.p -- test
;

	include 'include.i'
	include	'offsets.i'
	include	'macro.i'

SysBase	equ	4

; point

X	equ	0
Y	equ	2

; window

XL	equ	0
YB	equ	2
XR	equ	4
YT	equ	6

; vars

lastvar	set	0

	var.l IntuitionBase
	var.l GfxBase
	var.l screen
	var.l rp
	var.w line,4
	var.w rndseed

;

start	link	vr,#lastvar		; alloc & clear vars
	move.w	#-lastvar/2,d0
	lea	lastvar(vr),a0
	bra.s	001$
000$	clr.w	(a0)+
001$	dbra	d0,000$

	lea	GfxName(pc),a1		; open graphics
	moveq	#0,d0
	call	SysBase,OpenLibrary
	move.l	d0,GfxBase(vr)
	beq	exit

	lea	IntuitionName(pc),a1	; open intuition
	moveq	#0,d0
	call	OpenLibrary
	move.l	d0,IntuitionBase(vr)
	beq	exit

	move.l	d0,a6			; open screen
	lea	newscr(pc),a0
	call	OpenScreen
	move.l	d0,screen(vr)
	beq	exit
	
	move.l	d0,a0			; get RastPort address
	lea	sc_RastPort(a0),a0
	move.l	a0,rp(vr)

	move.w	#7051,rndseed(vr)	; init rndseed

	lea	wind(pc),a2		; load window ptr

	move.l	GfxBase(vr),a6

	moveq	#1,d0
	move.l	rp(vr),a1
	call	SetAPen
	move.l	#RP_COMPLEMENT,d0
	move.l	rp(vr),a1
	call	SetDrMd

	move.w	#319,d2			; draw 10000 lines

yyy	move.w	d2,line(vr)
	move.w	#0,line+2(vr)
	move.w	#319,line+4(vr)
	sub.w	d2,line+4(vr)
	move.w	#255,line+6(vr)
	lea	line(vr),a0
	lea	line+4(vr),a1
	bsr	clip
	dbra	d2,yyy

	move.w	#255,d2

aaa	move.w	#0,line(vr)
	move.w	d2,line+2(vr)
	move.w	#319,line+4(vr)
	move.w	#255,line+6(vr)
	sub.w	d2,line+6(vr)
	lea	line(vr),a0
	lea	line+4(vr),a1
	bsr	clip
bbb	dbra	d2,aaa


	moveq	#100,d2			; wait 2 seconds
zzz	call	WaitTOF
	dbra	d2,zzz

exit	tst.l	IntuitionBase(vr)	; test intuition
	beq.s	000$
	tst.l	screen(vr)		; test screen
	beq.s	001$
	move.l	screen(vr),a0		; close screen
	call	IntuitionBase(vr),CloseScreen
001$	move.l	IntuitionBase(vr),a1	; close intuition
	call	SysBase,CloseLibrary
000$	tst.l	GfxBase(vr)		; test graphics
	beq.s	002$
	move.l	GfxBase(vr),a1		; close graphics
	call	SysBase,CloseLibrary
	unlk	vr			; restore stack
	moveq	#0,d0			; exit(0)
002$	rts
	
rnd	
{
	rndseed(vr) d0 rndseed(vr) = #31421 * #6927 + = .
	d0 #320 / % .
}
	rts

; code (a0),(a2) -> d0 -- calculate visibility code for clip

code	moveq	#0,d0
{
	d0 X(a0) = XL(a2) == . 
		iflt d0 #16 <1 . else
			d0 XR(a2) == . ifgt d0 #17 <1 . then then 

	d0 Y(a0) = YB(a2) == . 
		iflt d0 #18 <1 . else
			d0 YT(a2) == . ifgt d0 #19 <1 . then then 
	d0 % .
}
	rts

; clip (a0)-(a1),(a2) ->d0 -- clip line (a0)-(a1) to window (a2), d0=0 if succ

clip	movem.l	d2-d5,-(sp)

	bsr	code
	exg.l	a1,a0
	move.w	d0,d1
	bsr	code
{
	begin

	d3 d0 = d1 & .
}
	bne	exclip
{
	d0 0= . ifeq a0 a1 :=: . d0 d1 :=: . then
	d0 0= .
	while
	d0 #0 <? . ifne
		Y(a0) d3 Y(a1) = Y(a0) - 
			d4 XL(a2) = X(a0) -
			d5 X(a1) = X(a0) - */ + .
		X(a0) XL(a2) = .
	else d0 #1 <? . ifne
		Y(a0) d3 Y(a1) = Y(a0) - 
			d4 XR(a2) = X(a0) -
			d5 X(a1) = X(a0) - */ + .
		X(a0) XR(a2) = .
	else d0 #2 <? . ifne
		X(a0) d3 X(a1) = X(a0) -
			d4 YB(a2) = Y(a0) -
			d5 Y(a1) = Y(a0) - */ + .
		Y(a0) YB(a2) = .
	else d0 #3 <? . ifne
		X(a0) d3 X(a1) = X(a0) -
			d4 YT(a2) = Y(a0) -
			d5 Y(a1) = Y(a0) - */ + .
		Y(a0) YT(a2) = .
	then then then then
}
	bsr	code
{
	repeat
}
	move.l	a1,-(sp)		; draw line
	movem.w	(a0),d0-d1
	move.l	rp(vr),a1
	call	Move
	move.l	(sp)+,a0
	movem.w	(a0),d0-d1
	move.l	rp(vr),a1
	call	Draw
exclip	movem.l	(sp)+,d2-d5

	rts

; data

newscr	dc.w	0,0,320,256,		; left top widht height
	dc.w	2,			; depth
	dc.b	0,1,			; detailpen blockpen
	dc.w	0,CUSTOMSCREEN,		; wiewmodes type
	dc.l	font,			; font
	dc.l	title,			; title
	dc.l	0,0			; gadgets custombitmap

font	dc.l	fontnam,
	dc.w	TOPAZ_EIGHTY,
	dc.b	FS_NORMAL,FPF_ROMFONT

wind	dc.w	50,50,270,205

IntuitionName
	dc.b	'intuition.library',0
GfxName	dc.b	'graphics.library',0

title	dc.b	'Test screen',0
fontnam	dc.b	'topaz.font',0

	ds.w	0

	end