driven: add another wipe effect

demos/driven/part10_graphics/Makefile

@@ -16,7 +16,8 @@ graphics.o:	graphics.s \
 	graphics/a2_atrus.hgr.zx02 \
 	graphics/riven_233.aux.zx02 \
 	graphics/riven_233.bin.zx02 \
-	wipes/fx.hgr.center.by.pixel.s
+	wipes/fx.hgr.center.by.pixel.s \
+	wipes/fx.hgr.fizzle.s
 	ca65 -o graphics.o graphics.s -l graphics.lst
 
 ###

demos/driven/part10_graphics/graphics.s

@@ -154,9 +154,11 @@ graphics:
 	sta	zx_src_l+1
 	lda	#>floater_graphics
 	sta	zx_src_h+1
-	lda	#$20
+	lda	#$40
 	jsr	zx02_full_decomp
 
+	jsr	do_wipe_fizzle
+
 	jsr	wait_until_keypress
 
 	lda	#0
@@ -231,4 +233,5 @@ atrus_message2:
 .byte 0,23,"time before the submission deadline.",0
 
 .include "wipes/fx.hgr.center.by.pixel.s"
+.include "wipes/fx.hgr.fizzle.s"
 

demos/driven/part10_graphics/wipes/fx.hgr.fizzle.s

@@ -0,0 +1,62 @@
+;license:MIT
+;(c) 2017-2021 by qkumba/4am/John Brooks
+
+; vmw - convert to ca65, de-macro a bit
+
+	; original copied to 0 page for speed
+	; we don't really need that much speed here?
+	; also we need the zero page
+
+do_wipe_fizzle:
+
+	; OVERCOPY_TO_0 start, end
+	;$FF clobbered
+	;X=0
+	;Y=0
+	;jmp   loop
+
+;start:
+;.org $00
+;!pseudopc 0 {
+         ;X=0
+         ;Y=0
+
+	ldx	#0
+	ldy	#0
+
+fizzle_loop:
+	txa
+fizzle_loop1:
+	eor	#$1B                  ; LFSR form 0x1B00 with period 8191
+fwait:
+	dex
+	bne	fwait
+	tax
+fizzle_loop2:
+	txa
+	ora	#$20		; change high dest page (page1)
+	sta	dst+2
+	eor	#$60
+	sta	src+2		; change high src page (page2)
+	jsr	src		; copies from page2 to page1
+
+	txa
+	lsr
+	tax
+	tya
+	ror
+	tay
+	bcc	fizzle_loop2
+	bne	fizzle_loop
+	bit	KEYPRESS
+	bmi	fexit
+	txa
+	bne	fizzle_loop1
+
+src:
+	lda	$FD00, Y		; SMC high byte
+dst:
+	sta	$FD00, Y		; SMC high byte
+fexit:
+	rts
+