graphic12.src

	.page
	.subttl 'graphics12'
;********************************************************
;
;  draw {s} { ,p !  to p }
;
;	   where:
;		  s    = optional color selection (1-4)
;		  p    = point to plot
;		  to p = draw a line to the point p
;
;********************************************************

draw
	jsr isgrap	;make sure graphics area has been allocated
	jsr chrgot
	beq draw15	;nothing follows 'draw', so quit
	ldx #1		;default to foreground color,
	cmp #totk	;if 'draw ,' or 'draw to'
	jsr incol1      ;get color, or set up default

draw10
	jsr chrgot
	cmp #','
	beq draw20      ;statement of form ',p'
	cmp #totk
	beq draw20      ;'to p'
draw15
	rts		;ok if end of statement, anything else will crash

draw20
	pha
	jsr chrget      ;skip over comma or semicolon
	ldx #xdest-vwork
	jsr incord
	pla
	bpl draw40      ;branch if ','

	jsr drawln
	jmp draw10

draw40
	jsr dstpos
	jsr gplot	;plot to the point
	jmp draw10



;*************************************************************
;
; set the current xpos, ypos
;
;	   locate p
;
;*************************************************************

locate
	jsr isgrap	;make sure graphics area has been allocated
	ldx #xdest-vwork
	jsr incord      ;get the coordinates
	jmp dstpos      ;set the pos'n, do rts

	.page
;*************************************************************
;
; set a color
;
;	  color n, v {,l}
;
;      where:
;	      n = 0 for background color
;		   1     foreground
;		   2     multicolor 1
;		   3     multicolor 2
;		   4     border
;	      v = color (1-16)
;	      l = optional luminance (0-7) (def.=7)
;
;************************************************************

scolor
	jsr getbyt      ;get selection in x
	cpx #5
	bcs sclerr      ;illegal value
	stx tmpton      ;save temp

	jsr combyt      ;comma, color in x
	dex
	cpx #16
	bcs sclerr
	stx tmpton+1

	ldx #7
	jsr optbyt      ;get optional luminance, default=7
	cpx #8
	bcs sclerr

	txa		;pack color/lum in acc.
	asl a		;move lim to high nybble
	asl a
	asl a
	asl a
	ora tmpton+1    ;or in color

	ldx tmpton      ;where does this color/lum go?
	cpx #1
	beq scol10
	bcs scol20

	sta ted+21      ;background
	bne scol99      ;always

scol10
	sta fg		;foreground
	sta color	;set current text color, also.
	beq scol99      ;always

scol20
	cpx #3
	beq scol30
	bcs scol40

	sta mc1		;multicolor 1
	bne scol99      ;always

scol30
	sta ted+22      ;multicolor 2
	beq scol99      ;always

scol40
	sta ted+25      ;border
scol99
	rts

sclerr
	jmp fcerr	;illegal value error



;*********************************************************
;
; scnclr...   clear current screen
;
;*********************************************************

scnclr
	lda graphm      ;which mode are we in?
	bne scnc10      ;branch if not text.
scnc05
	lda #$93	;print 'cls'
	jmp bsout

scnc10
	and #$40	;split screen?
	beq scnc15      ;branch if not.
	jsr scnc05      ;first clear text screen,
	ldx #nlines-5   ;then position cursor.
	ldy #0
	clc
	jsr jplot

scnc15
	lda #0
	ldy #>grbase
	ldx #32
	jsr scnc80      ;fill 8k bit map area with 0

	jsr getcol	;get packed byte of colors for current mode
	ldy #>bmcolr
	ldx #4
	jsr scnc80      ;fill 1k vm area with color info.

	jsr getlum      ;get packed luminance levels
	ldy #>bmlum
	ldx #4
	jsr scnc80      ;fill 1k attr area with luminance info.
	lda #0
	ldx #3
scnc60
	sta xpos,x      ;set current pos to top left
	dex
	bpl scnc60
	rts

scnc80			;general fill sub.: save a for x pages, starting at (0,y)
	sty grapnt+1
	ldy #0
	sty grapnt
scnc85
	sta (grapnt),y
	dey
	bne scnc85
	inc grapnt+1
	dex
	bne scnc85
	rts



;****************************************************************
;
;  scale n      :turn the scale mode on (n=1) or off (n=0)
;
;***************************************************************

scale
	jsr getbyt
	cpx #2
	bcs sclerr      ;illegal value
	stx scalem      ;0 if off, 1 if on
	rts

;.end