# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1547088462 -7200
# Node ID d63782badb6b97584929ebcdd3f7b17096419ec4
# Parent  cacfa0888410a6c15c6a1e78e3c8addb5336698b
nicer distortion

diff -r cacfa0888410 -r d63782badb6b Makefile
--- a/Makefile	Thu Jan 10 04:16:47 2019 +0200
+++ b/Makefile	Thu Jan 10 04:47:42 2019 +0200
@@ -19,8 +19,12 @@
 clean:
 	rm -f $(obj) $(bin) $(img)
 
+.PHONY: run
+run: $(img)
+	sameboy $<
+
 logo.tiles: logo.png
 	rgbgfx -T -u -o $@ $<
 
-sin.inc:
+sin.inc: gensine
 	./gensine >$@
diff -r cacfa0888410 -r d63782badb6b test.asm
--- a/test.asm	Thu Jan 10 04:16:47 2019 +0200
+++ b/test.asm	Thu Jan 10 04:47:42 2019 +0200
@@ -46,17 +46,52 @@
 
 	xor a, a
 	ld b, a
+
 	ldh a, [REG_LY]
-	add a, d
+	add a, d	; add frame number
 	ld c, a
 
 	ld hl, sintab
-	add hl, bc	; hl points to sin value (0-64)
+	add hl, bc	; hl now points to the sine value
 
-	ld a, yoffs_center
-	add a, [hl]
+	ld a, [hl]
+
+	; add a half-octave sine
+	ld e, a		; save first sine to e
+	sla d
+	ld a, [REG_LY]
+	sla a
+	add a, d
+	ld c, a
+	srl d
+
+	ld hl, sintab
+	add hl, bc
+	ld a, [hl]
+	sra a
+	add a, e	; add previously saved sine
+
+	add a, yoffs_center
 	ldh [REG_SCY], a
 
+	; do something for SCX too
+	ld a, d
+	sla a
+	ld d, a
+
+	ldh a, [REG_LY]
+	add a, 32
+	add a, d	; add frame number
+	ld c, a
+
+	ld hl, sintab
+	add hl, bc
+
+	ld a, [hl]
+	sra a
+	add a, xoffs_center
+	ldh [REG_SCX], a
+
 	; done, wait until we're out of hsync
 .wait_endhsync:
 	ldh a, [REG_STAT]