From df4be961d2e879e9d334610cba67d11599a2e5d8 Mon Sep 17 00:00:00 2001
From: Vince Weaver <vincent.weaver@maine.edu>
Date: Tue, 12 Dec 2017 15:39:32 -0500
Subject: [PATCH] mode7: working on checkerboard

---
 mode7/checkerboard_lookup.s |  17 +++++++++++++++++
 mode7/mode7.dsk             | Bin 143360 -> 143360 bytes
 mode7/mode7.s               |  17 ++++++++++++++++-
 3 files changed, 33 insertions(+), 1 deletion(-)
 create mode 100644 mode7/checkerboard_lookup.s

diff --git a/mode7/checkerboard_lookup.s b/mode7/checkerboard_lookup.s
new file mode 100644
index 00000000..d5649032
--- /dev/null
+++ b/mode7/checkerboard_lookup.s
@@ -0,0 +1,17 @@
+	;====================
+	; lookup_map
+	;====================
+	; finds value in space_x.i,space_y.i
+	; returns color in A
+	; CLOBBERS: A,Y
+
+	lda	SPACEX_I                                                ; 3
+	sta	spacex_label+1  ; self modifying code, LAST_SPACEX_I    ; 4
+
+	lda	SPACEY_I                                                ; 3
+	sta	spacey_label+1  ; self modifying code, LAST_SPACEY_I    ; 4
+
+
+	lda	#$11			; always red
+
+	sta	map_color_label+1	; self-modifying
diff --git a/mode7/mode7.dsk b/mode7/mode7.dsk
index e9ea42bcbbcb3b65d47473913ca73d42e1f3630a..15e6f26c8c8e8a75f4c6b3f8924cbc47c4531506 100644
GIT binary patch
delta 1129
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z`h&aM_E<<d5}m>ZMBEA^I|0GqgI!RueF)johoyZe^eKuap@k)G8l`Nq>Ajovr`Go6
z%*=Pb@0@SWiOp2SW~wf;1);fbZO|XAXNNHx$1Fs|o}G0fc(2ZN35$33dBvf7gYWLe
znV+(6va=pl11o9_mX!w<sT{T%f<^d~`Hd2uvhhu@DDRXYb_`DqvmuWh)~8J62EQ_3
ztMb9Bnt>v_VI)qsYIVLL3O&<lJ6iH+aFaXbT>Bg#acfCq;^Ta^YcCe@_gbS)XVdPW
zJDu-X>!0lWKaRQv<tGcc<S$ZIEB|B9<NxuOUtxL5>}r3cjqQGhIQa}Qv28vN%d_S`
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zIe3}MZVRQ-$Ok7Bf~dj}x6fD`n;<6#VMrdOR#j<y2Pnj+({_weC)eZ5m0Fem&S^yG
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z2XW4@{19Ti7CUZes2}=ALJ^2u2*@zsj%9=gvD(ac;KY$??bZE1$Z!T_uPM~I;+^f5
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dueb^WhW6dn<GS|SMy>j*t_JODSA*-a{x_#V-c$ep

delta 1132
zcmaJ;ZD?Cn7{2GWj+&JAE<5+;WUl6P#+o}8EQM;V)(_kd3;B@=O3^=eSu=W5o$17O
zPFWJ%J7wk6)gxS?3RQMWt|+t&HX;l*gwl=)nTUemHen4zA#{mzNWZ){&9;iwKkqsB
zdEe(e&wZcFwT8^KhH1JeH+wnqT=goqJyc+N1ye6?J=VhYn>*wR=6m;S<FDKte(C_8
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zaWx&$>_r&08z8Q)=EP|48jP}5+`HB;+XWWF`FH%#Hs@55D8VB{#7!xem$t)ETY|KW
zA?uu(E*c}phhaqQCuT!+dn*L8b9tv`h}#=**GkO#fA<jKN?)+&-n>XcS`5Nb_f3*`
z9R^P%UV~&UlnrAkXKZMF%(~Ex{Cgh5!es4u-3>_$y3C}*JP29#JQi<2hV@|A4M_~a
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zFtKJD(XR9dgpCpQHDPB+?;0B=Y@D!Z!tz9<*(Zd3PS|<3F+tcV!oDR_nXYrv*oySg
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S^m7wxd_NXMXJbKmTKOAT&EDz&

diff --git a/mode7/mode7.s b/mode7/mode7.s
index e76ce710..beb7a27b 100644
--- a/mode7/mode7.s
+++ b/mode7/mode7.s
@@ -1,3 +1,6 @@
+ISLAND_MAP = 0
+CHECKERBOARD_MAP = 1
+
 .include "zp.inc"
 
 ;===========
@@ -963,7 +966,11 @@ screenx_loop:
 
 nomatch:
 	; Get color to draw in A
+.if ISLAND_MAP=1
 	.include "island_lookup.s"
+.elseif CHECKERBOARD_MAP=1
+	.include "checkerboard_lookup.s"
+.endif
 
 match:
 
@@ -1055,7 +1062,13 @@ done_screeny:
 	; this is used to check if above water or grass
 	; the high-performance per-pixel version has been inlined
 lookup_map:
+
+.if ISLAND_MAP=1
 	.include "island_lookup.s"
+.elseif CHECKERBOARD_MAP=1
+	.include "checkerboard_lookup.s"
+.endif
+
 	rts								; 6
 
 	;=====================
@@ -1091,14 +1104,16 @@ exit:
 ;===============================================
 
 	; waste memory with a lookup table
-	; maybe faster than using GBASCALC?
+	; move this to the zeropage?
 
 gr_offsets:
 	.word	$400,$480,$500,$580,$600,$680,$700,$780
 	.word 	$428,$4a8,$528,$5a8,$628,$6a8,$728,$7a8
 	.word	$450,$4d0,$550,$5d0,$650,$6d0,$750,$7d0
 
+.if ISLAND_MAP=1
 .include "island_map.inc"
+.endif
 
 .include "fast_multiply.s"