;Part 2. Graphic samples. Subprograms of low level.

;Print string (text line) at the screen
;IY- addr. of the text line
;HL-x
;b-y,c- colour
pline
		ld	(plinex),hl
		ld	a,c
		cp	#ff
		jr	z,pline
		rlca
		rlca
		rlca
		rlca
		or	c
		ld	(printcol),a
pline1
		ld	a,(IY)
		cp	0
		ret	z
		cp	#16
		jp	z,plinecoor
		cp	#0d
		jp	z,pline_cr
		cp	#0A
		jp	z,pline_lf
		cp	#17
		jp	z,pline_tab
		call	print
		inc	hl
		inc	hl
		inc	hl
		inc	hl

		inc	IY
		jp	pline1




pline_tab
		push	bc
		ld	b,24
pline_tab1
		inc     hl
		djnz	pline_tab1
		pop	bc
		jp	pline1

pline_lf
		inc	b
		inc	b
		inc	b
		inc	b
		inc	b
		inc	b
		inc	b
		inc	b

		inc	IY
		jp	pline1

pline_cr
		ld	hl,(plinex)
		inc	IY
		jp	pline1

plinecoor
		inc	IY
		ld	a,(IY)
		ld	b,a
		ld	a,(IY+1)
		ld	l,a
		ld	a,(IY+2)
		ld	h,a
		inc	IY
		inc	IY
		inc	IY
		jp	pline1





plinex		defw	0



print_tab
;Print to symbol positions 
;B-y. C - x
;A - symbol
;Colour - last

		push	af
		push	bc
		ld	b,c
		ld	hl,0
		ld	de,6
print_tab1
		add	hl,de
		djnz	pline_tab1
		pop	bc
		ld	c,#ff
		pop	af
		jp	print





;Print to the screen (Pixels coordinates).
;6x8 pixels
print
;HL-x
;B-y
;C-colour, #FF - no change
;A-symbol

		push	ix
		push	hl
		push	de
		push	bc
		push	af
		ld	ix,printchar
		ld	(ix),a
		srl	h
		rr	l
		ld	(ix+1),l
		ld	(ix+2),h
		ld	(ix+3),b
		bit	7,c
		call	z,prncolor_change
		call	open_video_mem
		ld	a,(ix)
		ld	h,0
		ld	l,a
		add	hl,hl
		add	hl,hl
		add	hl,hl
		ex	de,hl
		ld	hl,font
		add	hl,de
		ld	(ix+4),l
		ld	(ix+5),h
; Loop of 8 pixels at the screen
		ld	a,8
print_lines
		push	af
		ld	d,(ix+2)
		ld	e,(ix+1)
		ld	hl,#4000
		add	hl,de
		ld	(pcuradr),hl
		ld	(pcuradr1),hl
		ld	a,(ix+3)
		out	(port_y),a
		ld	l,(ix+4)
		ld	h,(ix+5)
		ld	a,(hl)
		ld	c,a
		ld	a,3
print_point
		push	af
		ld	hl,(pcuradr1)
		ld	a,(hl)
		sla	c
		jr	nc,ppoint1
		and	%00001111
		ld	b,(ix+6)
		push	af
		ld	a,b
		and	%11110000
		ld	b,a
		pop	af
		or	b
ppoint1
		sla	c
		jr	nc,ppoint2
		and	%11110000
		ld	b,(ix+6)
		push	af
		ld	a,b
		and	%00001111
		ld	b,a
		pop	af
		or	b
ppoint2
		ld	(hl),a
		inc	hl
		ld	(pcuradr1),hl
		pop	af
		dec	a
		jp	nz,print_point
		ld	a,(ix+3)
		inc	a
		ld	(ix+3),a
		ld	h,(ix+5)
		ld	l,(ix+4)
		inc	hl
		ld	(ix+5),h
		ld	(ix+4),l
		ld	hl,(pcuradr)
		ld	(pcuradr1),hl
		pop	af
		dec	a
		jp	nz,print_lines
		pop	af
		pop	bc
		pop	de
		pop	hl
		pop	ix

		ret

prncolor_change
		ld	a,c
		rlca
		rlca
		rlca
		rlca
		or	c
		ld	(ix+6),a
		ret



pcuradr		defw	0
pcuradr1	defw	0
printchar	defb	0
printx		defw	0
printy		defb	0
printfnt	defw	0
printcol	defb	0




;Paint the point (dot).
set_point
;HL-x D-y, E-colour

		push	hl
		push	de

		push	de
		ld	a,e
		sla	e
		sla	e
		sla	e
		sla	e
		or	e
		ld	(modcolor),a
		pop	de
		ld	a,d
		ld	(pointy),a
		push	hl
		srl	h
		rr	l
		ld	(movex),hl
		pop	hl
		bit	0,l
		jp	z,set_point_p
		jp	set_point_np
set_point_p
		ld	a,%11110000
		ld	(set_point_cm),a
		xor	#ff
		ld	(set_point_sm),a
		jp	set_point_put


set_point_np
		ld	a,%00001111
		ld	(set_point_cm),a
		xor	#ff
		ld	(set_point_sm),a
		jp	set_point_put



set_point_put

		call	open_video_mem
		ld	a,(pointy)
		out	(port_y),a
		ld	hl,(movex)
		ld	d,h
		ld	e,l
		ld	hl,#4000
		add	hl,de
		ld	a,(hl)
		and	0
set_point_sm	equ	$-1
		ld	e,a
		ld	a,(modcolor)
		and	0
set_point_cm	equ	$-1
		or	e
		ld	(hl),a
		call 	close_video_mem
		pop	de
		pop	hl

		ret

modcolor	defb	0
pointy		defb	0
movex		defw	0

;Paint horizontal line
horline
		call	open_video_mem

		push	de
		ld	d,h
		ld	e,l
		ld	hl,#4000
		srl	d
		rr	e
		add	hl,de
		pop	de
		ld	a,d
		out	(port_y),a
		ld	a,e
		sla	a
		sla	a
		sla	a
		sla	a
		or	e
		ld	(hl),a
		ld	d,h
		ld	e,l
		inc	de
		srl	b
		rr	c
		ldir

		call	close_video_mem
		ret





verline
;HL-x, D-y, E-colour, B-length
		call	set_point
		inc	d
		djnz	verline
		ret


box
;HL-x,D-y,E-colour, BC-length, A-height
		push	af
		push	hl
		push	de
		push	bc
		call	horline
		pop	bc
		pop	de
		pop	hl
		pop	af
		push	af
		push	hl
		push	de
		push	bc
		add	a,d
		ld	d,a
		call	horline
		pop	bc
		pop	de
		pop	hl
		pop	af
		push	af
		push	hl
		push	de
		push	bc
		ld	b,a
		call	verline
		pop	bc
		pop	de
		pop	hl
		pop	af
		add	hl,bc
		ld	b,a
		call	verline
		ret



fbox
;HL-x,D-y,E-colour, BC-length, A-height
		push	ix
		call	open_video_mem
		ld	ix,box_x
;Loading of variables
		res	0,c
		srl	b
		rr	c
		ld	(ix+3),c
		ld	(ix+4),b
		res	0,l
		srl	h
		rr	l
		ld	(ix+1),h
		ld	(ix),l
		ld	(ix+2),d
		ld	(ix+5),a
		ld	a,e
		rlca
		rlca
		rlca
		rlca
		or	e
		ld	(ix+6),a

fbox1
		ld	a,(ix+2)
		out 	(port_y),a
		inc	a
		ld	(ix+2),a
		ld	d,(ix+1)
		ld	e,(ix)
		ld	hl,#4000
		add	hl,de
		ld	d,h
		ld	e,l
		inc	de
		ld	b,(ix+4)
		ld	c,(ix+3)
		ld	a,(ix+6)
		ld	(hl),a
		ldir
		ld	a,(ix+5)
		dec	a
		jr	z,fbox2
		ld	(ix+5),a
		jp	fbox1
fbox2
		pop	ix
		call	close_video_mem
		ret

box_x		defw	0	;+0 +1
box_y		defb	0	;+2
box_l		defw	0	;+3 +4
box_h		defb	0	;+5
box_c		defb	0	;+6


putspr
;HL-x, D-y, E-empty, BC-length, A - height, iy - address
		call	open_video_mem1
		ld	(spr_adr),iy
		ld	iy,spr_cox
		srl	h
		rr	l
		ld	(iy),l
		ld	(iy+1),h
		srl	b
		rr	c
		ld	(iy+4),b
		ld	(iy+3),c
		ld	(iy+2),d
		ld	(iy+5),a

putspr1
		ld	a,(iy+2)
		out	(port_y),a
		ld	d,(iy+1)
		ld	hl,#4000
		ld	d,(iy+1)
		ld	e,(iy)
		add	hl,de
		ld	d,h
		ld	e,l
		ld	hl,(spr_adr)
		ld	b,(iy+4)
		ld	c,(iy+3)

		ldir
		ld	(spr_adr),hl
		ld	a,(spr_hei)
		dec	a
		ret	z
		ld	(spr_hei),a
		ld	a,(iy+2)
		inc	a
		ld	(iy+2),a
		jp	putspr1
		call	close_video_mem
		ret



spr_cox		defw	0	;+0 +1
spr_coy		defb	0	;+2
spr_len		defw	0	;+3 +4
spr_hei		defb	0	;+5
spr_adr		defw	0	;+6 +7



getspr
		ret