xdraw: add shimmer effect

graphics/hgr/xdraw/Makefile

@@ -8,7 +8,7 @@ LINKERSCRIPTS = ../../../linker_scripts
 
 all:	xdraw.dsk
 
-xdraw.dsk:	HELLO TINY_XDRAW TINY_COOL TINY_LINES TINY_CENTER NYAN XDRAW_TEST
+xdraw.dsk:	HELLO TINY_XDRAW TINY_COOL TINY_LINES TINY_CENTER NYAN XDRAW_TEST SHIMMER
 	cp $(EMPTYDISK) xdraw.dsk
 	$(DOS33) -y xdraw.dsk SAVE A HELLO
 	$(DOS33) -y xdraw.dsk BSAVE -a 0xE7 TINY_XDRAW
@@ -17,6 +17,7 @@ xdraw.dsk:	HELLO TINY_XDRAW TINY_COOL TINY_LINES TINY_CENTER NYAN XDRAW_TEST
 	$(DOS33) -y xdraw.dsk BSAVE -a 0xE7 TINY_CENTER
 	$(DOS33) -y xdraw.dsk BSAVE -a 0xC00 NYAN
 	$(DOS33) -y xdraw.dsk BSAVE -a 0xE7 XDRAW_TEST
+	$(DOS33) -y xdraw.dsk BSAVE -a 0xC00 SHIMMER
 
 ###
 
@@ -74,9 +75,18 @@ NYAN:	nyan.o
 nyan.o:	nyan.s
 	ca65 -o nyan.o nyan.s -l nyan.lst
 
+###
+
+SHIMMER:	shimmer.o
+	ld65 -o SHIMMER shimmer.o -C $(LINKERSCRIPTS)/apple2_c00.inc
+
+shimmer.o:	shimmer.s
+	ca65 -o shimmer.o shimmer.s -l shimmer.lst
+
+
 
 
 ####
 
 clean:	
-	rm -f *~ *.o *.lst HELLO TINY_COOL TINY_XDRAW TINY_LINES TINY_CENTER NYAN XDRAW_TEST
+	rm -f *~ *.o *.lst HELLO TINY_COOL TINY_XDRAW TINY_LINES TINY_CENTER NYAN XDRAW_TEST SHIMMER

graphics/hgr/xdraw/shimmer.s

@@ -0,0 +1,149 @@
+
+; zero page locations
+HGR_SHAPE	=	$1A
+SEEDL		=	$4E
+FRAME		=	$A4
+OUR_ROT		=	$A5
+RND_EXP		=	$C9
+HGR_PAGE	=	$E6
+HGR_SCALE	=	$E7
+HGR_ROTATION	=	$F9
+DIRECTION	=	$FC
+XPOS		=	$FD
+YPOS		=	$FF
+
+; Soft Switches
+KEYPRESS	=	$C000
+KEYRESET	=	$C010
+SPEAKER		=	$C030
+PAGE0           =       $C054
+PAGE1           =       $C055
+
+; ROM calls
+RND		=	$EFAE
+HGR2		=	$F3D8
+HCLR		=	$F3F2
+HCLR_COLOR	=	$F3F4
+HPOSN		=	$F411
+XDRAW0		=	$F65D
+TEXT		=	$FB36	; Set text mode
+WAIT		=	$FCA8	; delay 1/2(26+27A+5A^2) us
+
+
+shimmer:
+
+	;=========================================
+	; SETUP
+	;=========================================
+
+
+	jsr	HGR2
+
+	lda	#0
+	sta	FRAME
+
+	lda	#14
+	sta	YPOS
+
+	lda	#3
+	sta	HGR_SCALE
+
+	lda	#32
+	sta	DIRECTION
+
+	lda	#22		; only set once, we wrap 
+	sta	XPOS
+
+y_loop:
+
+
+x_loop:
+
+main_loop:
+
+	;=======================
+	; xdraw
+	;=======================
+
+xdraw:
+	; setup X and Y co-ords
+
+	ldy	#0		; XPOSH always 0 for us
+	ldx	XPOS
+	lda	YPOS
+	jsr	HPOSN		; X= (y,x) Y=(a)
+
+	ldx	#<shape_dsr
+	ldy	#>shape_dsr
+
+	lda	#0		; set rotation
+
+	jsr	XDRAW0		; XDRAW 1 AT X,Y
+				; Both A and X are 0 at exit
+
+
+	inc	FRAME
+	lda	FRAME
+	and	#$7
+	beq	reverse
+
+add_x:
+	lda	XPOS
+	clc
+	adc	DIRECTION
+	sta	XPOS
+	jmp	x_loop
+
+reverse:
+	lda	DIRECTION		; switch direction
+	eor	#$ff
+	sec
+	adc	#0
+	sta	DIRECTION
+
+	lda	YPOS
+	clc
+	adc	#16
+	sta	YPOS
+	cmp	#190
+	bne	y_loop
+
+
+do_shimmer_y:
+
+	ldx	#0
+do_shimmer_x:
+
+blargh:
+	lda	$4000,X
+	eor	#$80
+blargh2:
+	sta	$4000,X
+	inx
+	bne	do_shimmer_x
+
+
+	inc	blargh+2
+	inc	blargh2+2
+
+	lda	blargh+2
+	cmp	#$60
+	bne	do_shimmer_y
+
+	lda	#$40
+	sta	blargh+2
+	sta	blargh2+2
+	jmp	do_shimmer_y
+
+end:
+	jmp	end
+
+shape_dsr:
+.byte	$2d,$36,$ff,$3f
+.byte	$24,$ad,$22,$24,$94,$21,$2c,$4d
+.byte	$91,$3f,$36,$00
+
+
+
+
+