From ee0ae37c8903d372b03a54a83a22c42f024a926e Mon Sep 17 00:00:00 2001
From: Vince Weaver <vince@deater.net>
Date: Sat, 20 Jan 2024 16:24:22 -0500
Subject: [PATCH] trogdor: magnify copy works, but too slow

---
 demos/trogdor/hgr_copy_magnify.s | 122 ++++++++++++++++++++++++-------
 demos/trogdor/trogdor.s          |   2 +
 2 files changed, 98 insertions(+), 26 deletions(-)

diff --git a/demos/trogdor/hgr_copy_magnify.s b/demos/trogdor/hgr_copy_magnify.s
index 4d22e873..cb8dee98 100644
--- a/demos/trogdor/hgr_copy_magnify.s
+++ b/demos/trogdor/hgr_copy_magnify.s
@@ -2,28 +2,33 @@
 	; hgr copy from page in A to current DRAW_PAGE but magnify 2x
 	;=========================================================
 
-	; would be faster if we unroll it, but much bigger
-
-	; At first from left side of image, eventually arbitrary?
-
-	; destination in A?
-
 hgr_copy_magnify:
 
-	; for (y=0;y<192;y++) {
-	;	for(x=0;x<40;x+=2) {
-	;		A=src[x];
-	;		dest[x]=lookup1[A];
-	;		dest[x+1]=lookup2[A];
-	;		y++;
-	;		dest[x]=lookup1[A];
-	;		dest[x+1]=lookup2[A];
-	;	}
-	; }
-
+INPUT_OFFSET = 20
 
 	ldx	#0
 magnify_outer_loop:
+	txa
+	pha
+	clc
+	adc	#INPUT_OFFSET
+	tax
+
+	lda	hposn_low,X
+	sta	INL
+
+	lda	hposn_high,X
+	clc
+	adc	#$40		; hardcode at $60
+	sta	INH
+
+	pla
+
+	pha
+
+	asl
+	tax
+
 	lda	hposn_low,X
 	sta	OUTL
 
@@ -32,25 +37,90 @@ magnify_outer_loop:
 	adc	DRAW_PAGE
 	sta	OUTH
 
+	inx
 
 	lda	hposn_low,X
-	sta	INL
+	sta	GBASL
+
 
 	lda	hposn_high,X
 	clc
-	adc	#$40
-	sta	INH
+	adc	DRAW_PAGE
+	sta	GBASH
+
 
 	ldy	#0
 magnify_inner_loop:
-	lda	(INL),Y
-	sta	(OUTL),Y
-	iny
-	cpy	#40
-	bne	magnify_inner_loop
+	lda	(INL),Y					 	; 5
+	and	#$f						; 2
+	tax							; 2
+	lda	magnify_table_low,X				; 4
+	sta	(OUTL),Y					; 6
+	sta	(GBASL),Y					; 6
+
+	inc	OUTL						; 5
+	inc	GBASL						; 5
+
+	lda	(INL),Y						; 5
+	lsr							; 2
+	lsr							; 2
+	lsr							; 2
+	tax							; 2
+	lda	magnify_table_high,X				; 4
+	sta	(OUTL),Y					; 6
+	sta	(GBASL),Y					; 6
+
+	iny							; 2
+	cpy	#20						; 2
+	bne	magnify_inner_loop				; 2/3
+
+	pla
+	tax
 
 	inx
-	cpx	#192
+	cpx	#96
 	bne	magnify_outer_loop
 
 	rts
+
+
+	; XXXXABCD = XA BB CC DD
+magnify_table_low:
+	.byte	$00	; 0000 => 000 0000
+	.byte	$03	; 0001 => 000 0011
+	.byte	$0C	; 0010 => 000 1100
+	.byte	$0F	; 0011 => 000 1111
+	.byte	$30	; 0100 => 011 0000
+	.byte	$33	; 0101 => 011 0011
+	.byte	$3C	; 0110 => 011 1100
+	.byte	$3F	; 0111 => 011 1111
+
+	.byte	$40	; 1000 => 100 0000
+	.byte	$43	; 1001 => 100 0011
+	.byte	$4C	; 1010 => 100 1100
+	.byte	$4F	; 1011 => 100 1111
+	.byte	$70	; 1100 => 111 0000
+	.byte	$73	; 1101 => 111 0011
+	.byte	$7C	; 1110 => 111 1100
+	.byte	$7F	; 1111 => 111 1111
+
+
+	; XEFGABCD = XE EF FG GA
+magnify_table_high:
+	.byte	$00	; 0000 => 000 0000
+	.byte	$01	; 0001 => 000 0001
+	.byte	$06	; 0010 => 000 0110
+	.byte	$07	; 0011 => 000 0111
+	.byte	$18	; 0100 => 001 1000
+	.byte	$19	; 0101 => 001 1001
+	.byte	$1E	; 0110 => 001 1110
+	.byte	$1F	; 0111 => 001 1111
+
+	.byte	$60	; 1000 => 110 0000
+	.byte	$61	; 1001 => 110 0001
+	.byte	$66	; 1010 => 110 0110
+	.byte	$67	; 1011 => 110 0111
+	.byte	$78	; 1100 => 111 1000
+	.byte	$79	; 1101 => 111 1001
+	.byte	$7E	; 1110 => 111 1110
+	.byte	$7F	; 1111 => 111 1111
diff --git a/demos/trogdor/trogdor.s b/demos/trogdor/trogdor.s
index 8c44e99e..22e58018 100644
--- a/demos/trogdor/trogdor.s
+++ b/demos/trogdor/trogdor.s
@@ -59,6 +59,8 @@ trogdor_main:
 	ldy	#$7f
 	jsr	hgr_clear_screen
 
+	jsr	horiz_pan
+
 	jsr	hgr_page_flip
 
 	;======================================