From 17620f3fe1bb75e2910fe082c09495d36d2542c9 Mon Sep 17 00:00:00 2001
From: Vince Weaver <vince@deater.net>
Date: Wed, 6 Jan 2021 14:21:51 -0500
Subject: [PATCH] roto: almost there

---
 graphics/gr/rotozoom/gr_plot.s  |  7 +++--
 graphics/gr/rotozoom/gr_scrn.s  | 45 ++++++++++++---------------------
 graphics/gr/rotozoom/roto.s     |  3 +++
 graphics/gr/rotozoom/rotozoom.s | 40 ++++++++++++++++++++---------
 4 files changed, 50 insertions(+), 45 deletions(-)

diff --git a/graphics/gr/rotozoom/gr_plot.s b/graphics/gr/rotozoom/gr_plot.s
index 1ad15895..73154207 100644
--- a/graphics/gr/rotozoom/gr_plot.s
+++ b/graphics/gr/rotozoom/gr_plot.s
@@ -5,7 +5,7 @@
 	; Ycoord in YPOS
 	; color in COLOR
 plot:
-	lda	YPOS							; 2
+	lda	YPOS							; 3
 
 	lsr			; shift bottom bit into carry		; 2
 
@@ -19,15 +19,14 @@ plot_c_done:
 	stx	MASK							; 3
 
 	asl			; shift back (now even)			; 2
-	tay
+	tay								; 2
 
 	lda	gr_offsets,Y	; lookup low-res memory address		; 4
         clc								; 2
         adc	XPOS							; 3
         sta	GBASL							; 3
-        iny								; 2
 
-        lda	gr_offsets,Y                                            ; 4
+        lda	gr_offsets+1,Y						; 4
         adc	DRAW_PAGE	; add in draw page offset		; 3
         sta	GBASH							; 3
 
diff --git a/graphics/gr/rotozoom/gr_scrn.s b/graphics/gr/rotozoom/gr_scrn.s
index c28f7fce..07de0a73 100644
--- a/graphics/gr/rotozoom/gr_scrn.s
+++ b/graphics/gr/rotozoom/gr_scrn.s
@@ -7,23 +7,10 @@
 	; assume reading from $c00
 
 scrn:
-	lda	YPOS							; 2
+	lda	YPOS							; 3
 
-;	lsr			; shift bottom bit into carry		; 2
-
-;	bcc	scrn_even						; 2nt/3
-;scrn_odd:
-;	ldx	#$f0							; 2
-;	bcs	scrn_c_done						; 2nt/3
-;scrn_even:
-;	ldx	#$0f							; 2
-;scrn_c_done:
-;	stx	MASK							; 3
-
-;	asl			; shift back (now even)			; 2
-
-	and	#$fe		; make even
-	tay
+	and	#$fe		; make even				; 2
+	tay								; 2
 
 	lda	gr_offsets,Y	; lookup low-res memory address		; 4
         clc								; 2
@@ -34,26 +21,26 @@ scrn:
         adc	#$8	; assume reading from $c0			; 3
         sta	GBASH							; 3
 
-	ldy	#0
+	ldy	#0							; 2
 
-	lda	YPOS
-	lsr
-	bcs	scrn_adjust_even
+	lda	YPOS							; 3
+	lsr								; 2
+	bcs	scrn_adjust_even					;2nt/3t
 
 scrn_adjust_odd:
-	lda	(GBASL),Y	; top/bottom color
-	jmp	scrn_done
+	lda	(GBASL),Y	; top/bottom color			; 5+
+	jmp	scrn_done						; 3
 
 scrn_adjust_even:
-	lda	(GBASL),Y	; top/bottom color
+	lda	(GBASL),Y	; top/bottom color			; 5+
 
-	lsr
-	lsr
-	lsr
-	lsr
+	lsr								; 2
+	lsr								; 2
+	lsr								; 2
+	lsr								; 2
 
 scrn_done:
 
-	and	#$f
+	and	#$f							; 2
 
-	rts
+	rts								; 6
diff --git a/graphics/gr/rotozoom/roto.s b/graphics/gr/rotozoom/roto.s
index 4f7eec4a..32de8fc5 100644
--- a/graphics/gr/rotozoom/roto.s
+++ b/graphics/gr/rotozoom/roto.s
@@ -75,6 +75,9 @@ wait_for_keypress:
 	bit	KEYRESET
 
 	inc	ANGLE
+	lda	ANGLE
+	and	#$f
+	sta	ANGLE
 
 	jmp	main_loop
 
diff --git a/graphics/gr/rotozoom/rotozoom.s b/graphics/gr/rotozoom/rotozoom.s
index abd0fd8c..9c31b0d4 100644
--- a/graphics/gr/rotozoom/rotozoom.s
+++ b/graphics/gr/rotozoom/rotozoom.s
@@ -49,6 +49,22 @@ rotozoom:
 	; cca = -20*ca;
 	; csa = -20*sa;
 
+	lda	#0
+	sta	CCAL
+	sta	CCAH
+	sta	CSAL
+	sta	CSAH
+
+
+	ldx	#20
+mul20_loop:
+
+
+
+	dex
+	bne	mul20_loop
+
+
 	; yca=cca+ycenter;
 
 	lda	CCAL
@@ -101,21 +117,21 @@ rotozoom_xloop:
 	; else if ((yp<0) || (yp>39)) color=0;
 	; else color=scrn_page(xp,yp,PAGE2);
 
-;	lda	#0
-;	ldx	XPH
-;	bmi	rotozoom_set_color
-;	cpx	#40
-;	bcs	rotozoom_set_color
-;	ldx	YPH
-;	bmi	rotozoom_set_color
-;	cpx	#40
-;	bcs	rotozoom_set_color
+	lda	#0
+	ldx	XPH
+	bmi	rotozoom_set_color
+	cpx	#40
+	bcs	rotozoom_set_color
+	ldx	YPH
+	bmi	rotozoom_set_color
+	cpx	#40
+	bcs	rotozoom_set_color
 
-	; scrn()
+	; scrn(xp,yp)
 
-	lda	XX
+	lda	XPH
 	sta	XPOS
-	lda	YY
+	lda	YPH
 	sta	YPOS
 
 	jsr	scrn