From 4246082e48dcbc31a5612d9c08cf7f6dda95439b Mon Sep 17 00:00:00 2001
From: Vince Weaver <vince@deater.net>
Date: Mon, 1 Apr 2024 01:25:52 -0400
Subject: [PATCH] keen: item pickup much better

also slower sadly
---
 games/keen/item_level1.s | 68 ++++++++++++++++++++++++++++++++++------
 games/keen/move_keen.s   | 23 +++++++++-----
 games/keen/zp.inc        | 10 +++---
 3 files changed, 79 insertions(+), 22 deletions(-)

diff --git a/games/keen/item_level1.s b/games/keen/item_level1.s
index a4a5c441..16384c1c 100644
--- a/games/keen/item_level1.s
+++ b/games/keen/item_level1.s
@@ -15,12 +15,17 @@ check_items:
 
 	; check head items
 
-	ldx	KEEN_HEAD_POINTER
+	ldx	KEEN_HEAD_POINTER_L
+	jsr	check_item
+	ldx	KEEN_HEAD_POINTER_R
 	jsr	check_item
 
 	; check feet items
 
-	ldx	KEEN_FOOT_POINTER
+	ldx	KEEN_FOOT_POINTER_L
+	jsr	check_item
+
+	ldx	KEEN_FOOT_POINTER_R
 	; fallthrough
 
 	;==================
@@ -78,10 +83,15 @@ done_item_pickup:
 	; big tilemap:
 	;	to find... urgh
 	;	X is currently (KEEN_Y/4)*20)+(KEEN_X/2)
+	;		(X mod 20) = KEEN_X/2
+	;		X/20 = KEEN_Y/4
+	;
 
-	lda	KEEN_Y			; divide by 4 as tile 4 blocks tall
-	lsr
-	lsr
+	lda	div20_table,X
+
+;	lda	KEEN_Y			; divide by 4 as tile 4 blocks tall
+;	lsr
+;	lsr
 
 	clc
 	adc	TILEMAP_Y		; add in tilemap Y (each row 256 bytes)
@@ -91,12 +101,13 @@ done_item_pickup:
 	lda	TILEMAP_X		; add in X offset of tilemap
 	sta	btc_smc+1
 
-	lda	KEEN_X
-	lsr
-	tay
-;	iny				; why add 1????
+	lda	mod20_table,X
 
-	lda	#0			; background tile
+;	lda	KEEN_X
+;	lsr
+	tay
+
+	lda	#1			; background tile
 btc_smc:
 	sta	$b000,Y
 
@@ -162,3 +173,40 @@ score_lookup:
 	; 3 = pizza			500 pts
 	; 4 = carbonated beverage	200 pts
 	; ? = bear			5000 pts
+
+
+; bit of a hack
+; TODO: auto-generate at startup
+
+div20_table:
+.byte	0,0,0,0,0, 0,0,0,0,0, 0,0,0,0,0, 0,0,0,0,0
+.byte	1,1,1,1,1, 1,1,1,1,1, 1,1,1,1,1, 1,1,1,1,1
+.byte	2,2,2,2,2, 2,2,2,2,2, 2,2,2,2,2, 2,2,2,2,2
+.byte	3,3,3,3,3, 3,3,3,3,3, 3,3,3,3,3, 3,3,3,3,3
+.byte	4,4,4,4,4, 4,4,4,4,4, 4,4,4,4,4, 4,4,4,4,4
+.byte	5,5,5,5,5, 5,5,5,5,5, 5,5,5,5,5, 5,5,5,5,5
+.byte	6,6,6,6,6, 6,6,6,6,6, 6,6,6,6,6, 6,6,6,6,6
+.byte	7,7,7,7,7, 7,7,7,7,7, 7,7,7,7,7, 7,7,7,7,7
+.byte	8,8,8,8,8, 8,8,8,8,8, 8,8,8,8,8, 8,8,8,8,8
+.byte	9,9,9,9,9, 9,9,9,9,9, 9,9,9,9,9, 9,9,9,9,9
+.byte	10,10,10,10,10, 10,10,10,10,10, 10,10,10,10,10, 10,10,10,10,10
+.byte	11,11,11,11,11, 11,11,11,11,11, 11,11,11,11,11, 11,11,11,11,11
+.byte	12,12,12,12,12, 12,12,12,12,12, 12,12,12,12,12 ;, 12,12,12,12,12
+
+
+mod20_table:
+.byte	0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19
+.byte	0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19
+.byte	0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19
+.byte	0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19
+.byte	0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19
+.byte	0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19
+.byte	0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19
+.byte	0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19
+.byte	0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19
+.byte	0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19
+.byte	0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19
+.byte	0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19
+.byte	0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19
+.byte	0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
+
diff --git a/games/keen/move_keen.s b/games/keen/move_keen.s
index 51ac4874..af8d8d76 100644
--- a/games/keen/move_keen.s
+++ b/games/keen/move_keen.s
@@ -403,11 +403,13 @@ keen_get_feet_even:
 
 	lda	tilemap,X		; put tilemap value in place
 	sta	KEEN_HEAD_TILE1
+	stx	KEEN_HEAD_POINTER_L
 	lda	tilemap+1,X
 	sta	KEEN_HEAD_TILE2
-	stx	KEEN_HEAD_POINTER
-
-	txa				; restore pointer to tile of head
+	txa
+	inx
+	stx	KEEN_HEAD_POINTER_R
+					; restore pointer to tile of head
 	clc
 	adc	#TILE_COLS		; one row down, now at foot
 	tax
@@ -415,12 +417,15 @@ keen_get_feet_even:
 	lda	tilemap,X		; put tilemap value in place
 	sta	KEEN_FOOT_TILE1
 	sta	KEEN_WALK_TILE_L
+	stx	KEEN_FOOT_POINTER_L
+
 	lda	tilemap+1,X
 	sta	KEEN_FOOT_TILE2
 	sta	KEEN_WALK_TILE_R
-	stx	KEEN_FOOT_POINTER
-
-	txa				; restore pointer to tile of foot
+	txa
+	inx
+	stx	KEEN_FOOT_POINTER_R
+					; restore pointer to tile of foot
 	clc
 	adc	#TILE_COLS		; one row down
 	tax
@@ -443,7 +448,8 @@ keen_get_feet_odd:
 	lda	tilemap+1,X		; put tilemap value in place
 	sta	KEEN_HEAD_TILE1
 	sta	KEEN_HEAD_TILE2
-	stx	KEEN_HEAD_POINTER
+	stx	KEEN_HEAD_POINTER_L
+	stx	KEEN_HEAD_POINTER_R
 
 	txa
 	clc
@@ -457,7 +463,8 @@ keen_get_feet_odd:
 	sta	KEEN_FOOT_TILE2
 	lda	tilemap+2,X
 	sta	KEEN_WALK_TILE_R
-	stx	KEEN_FOOT_POINTER
+	stx	KEEN_FOOT_POINTER_L
+	stx	KEEN_FOOT_POINTER_R
 
 	txa
 	clc
diff --git a/games/keen/zp.inc b/games/keen/zp.inc
index 74cb2d5c..bb9b8841 100644
--- a/games/keen/zp.inc
+++ b/games/keen/zp.inc
@@ -144,10 +144,12 @@ KEEN_HEAD_TILE1		= $A5
 KEEN_HEAD_TILE2		= $A6
 KEEN_WALK_TILE_L	= $A7
 KEEN_WALK_TILE_R	= $A8
-KEEN_FOOT_POINTER	= $A9
-KEEN_HEAD_POINTER	= $AA
-MARS_X			= $AB
-MARS_Y			= $AC
+KEEN_FOOT_POINTER_L	= $A9
+KEEN_FOOT_POINTER_R	= $AA
+KEEN_HEAD_POINTER_L	= $AB
+KEEN_HEAD_POINTER_R	= $AC
+MARS_X			= $AD
+MARS_Y			= $AE