From c55d07c16df27a4c6e56268b26f21bc429676798 Mon Sep 17 00:00:00 2001
From: blondie7575 <qd@quinndunki.com>
Date: Sat, 23 Dec 2017 19:01:16 -0700
Subject: [PATCH] Groundwork for span-based fill mode rendering

---
 V2Make.scpt   | Bin 2460 -> 2460 bytes
 gamemanager.s |  15 ++-
 graphics.s    |   4 +-
 gscats.2mg    | Bin 819264 -> 819264 bytes
 input.s       |   4 +-
 macros.s      |   9 ++
 terrain.s     | 336 +++++++++++++++++++++++++++++++++++++++++++++++++-
 7 files changed, 358 insertions(+), 10 deletions(-)

diff --git a/V2Make.scpt b/V2Make.scpt
index 050b92c37e624b7e7145f208a416c33e339945e9..eb180db3e574cd8fcbfb2819aeee9eaadc7db7d0 100644
GIT binary patch
delta 22
ecmbOuJV$s#J{!|p_Q{28eoUK_HXmfW%>)2kdk8=P

delta 22
ecmbOuJV$s#J{!}$?~@DJ{Fs&oZ9d3$n+X7C7YPFZ

diff --git a/gamemanager.s b/gamemanager.s
index 19a7c2e..0f4ee59 100644
--- a/gamemanager.s
+++ b/gamemanager.s
@@ -49,12 +49,15 @@ beginGameplay:
 gameplayLoop:
 
 	jsr syncVBL
+	BORDER_COLOR #$0
 
 	; Render the terrain if needed
-	lda terrainDirty
-	beq gameplayLoopKbd
-	jsr renderTerrain
+;	lda terrainDirty
+;	beq gameplayLoopKbd
+	BORDER_COLOR #$3
+	jsr renderTerrainFillMode
 	stz terrainDirty
+	BORDER_COLOR #$1
 
 	; Render players
 	jsr renderPlayers
@@ -113,8 +116,10 @@ gameplayLoopVictoryCondition:
 
 gameplayLoopEndFrame:
 	lda quitRequested
-	beq gameplayLoop
+	beq gameplayLoopContinue
 	jmp quitGame
+gameplayLoopContinue:
+	jmp gameplayLoop
 
 gameplayLoopShotTracking:
 	jsr trackActiveShot
@@ -287,7 +292,7 @@ fire:
 
 
 basePalette:
-	.word $0aef,$0080,$0861,$0c93,$0eb4,$0d66,$0f9a,$0000,$07b,$0000,$0000,$0000,$0000,$0000,$0000,$0FFF
+	.word $0aef,$0080,$0861,$0c93,$0eb4,$0d66,$0f9a,$0000,$007b,$0000,$0000,$0000,$0000,$0000,$0000,$0FFF
 
 
 
diff --git a/graphics.s b/graphics.s
index 19904d4..b5f449b 100644
--- a/graphics.s
+++ b/graphics.s
@@ -86,14 +86,14 @@ initSCBsLoop:
 ;
 ; X = Scan line
 ;
-; Trashes A
-
 enableFillMode:
+	SAVE_AXY
 	BITS8
 	lda $e19d00,x
 	ora #%00100000
 	sta $e19d00,x
 	BITS16
+	RESTORE_AXY
 	rts
 
 
diff --git a/gscats.2mg b/gscats.2mg
index 6c51db7f466ffab9dfdace08e225550dc2d56c4b..b0f9d8dfaa787aac14834d9098be324d5a0e4856 100644
GIT binary patch
delta 3540
zcmd^Bk5e4=760z;-Lf2;aM9S_ktpB%aN?=W>{y0b^9u;XgoF~Tsf`&oo+k%f3}YNf
zvU{MnG`UWGt%zrOU`UUmRF-Dd7$$fc6d4@3Oc-xkr;}1^AT>6rk}Qon)@rWryLXth
z)Bm8mu<w08-}m14ec$`O_q`$Yo+0&~*YfSNqKlT_gwS6RN0`Xn_Pl}_1QCWtca&}{
zTeG^Pazo_?K|lzxBd8elHCwYp(PB;n?Vqv~+Vdzs@F-8s3etnSPVBgL2eoM3_?Gj+
zJLu?SHjcq}SO|Vo=S?G?b7>^<>y|?9E5E+22H!<T{?by$&~$UOcpoLQ6wTP|Y_#PN
z<&JpS369D<k^9+qLrxkYJF+1P(TGJ1x{bc^U5HTMhTnO?VR*ocF#C*$?p#8@&U#Wv
zyPY<c&||mLNgMI!@)G*k68boq5ieon=zYaQ<0t6Lp6h?=2k|qsc&UQvjaM)+gsFI_
zl8MnktC(09ke@QKZXlbOSn&cX{vZ=u4P-MDn*g$fiJb@XFcVW3Qt_=!>=!`1Objog
z;yxy}a1rILV5*sB=6U8AGs1kte8KRx#kLi;O}6c}y|zwUzwM0e6Wh18x%Rv5W%h^d
zjrK$K%9re?>>t`cx7*nHYyn%rR<q6Q^XxHpg#C#9g5|RoXRXNEl(ju;Z&qhkf7Y3-
zPqMzvn#<kIm2nSqjocybCGHgWA@@0F%buTIklnVxJ<xKHx`hoP6t30tADJiWXDg@L
z<S?txLEUrabfG!hS=7UdmtI6+cDXB1OwH@5%}Z1x(-y8($Is)QhSs{FiDBHcW8Phx
zz3cSHP?*CXWG{1mUFU@i^l%RH^v2(+3cK}DBwpb9@Mg-<H~9XOt^mS)fi5tt!}=~|
zuxczKJ7<lKuIq7^3n=WaQ$G`@B67I4#~njx(sjUJ`yT7e?He7<2*d}g)Jc*|{BAbM
zcNaq4)d=kG<?us}i=#u;NSH=MAni);+wVWw+3yhbYIK1MbH^g`p_7hw@Gg|%-{XXZ
zM!zHBM5aS`BCX#MQ@2iDynNDe?4;w&VL5r0*dY=-ka<zxF(aXVls;^_N{biRz3vNc
z&$W~*kmAE^{O1i}H<;hIPq?$)<!2KqURaO_<vK4Pcf0(YFgsj(oPDoWIM)-smQ6WB
zVL9!osOv?LgkIQ->wv=%Sh5jpg>s)`KZVzWQrQ)#Ba}O8L3%VB_;&HqOQ`pBGMU-y
z|FZBp3xdSLsKw2woU>F&=pNBSxnUMU_uCv2In&|NUqpU3%&MQ^LOy5(kwh4w&H{dr
zMC{pB=8B6K)9gC)K7AZ%1^f)K!dy1PR+#IJ0{%Je7COa8zjIJ7E8fpKOb%ekoH}CB
z9QBk%x2XM4zB-&q4wv&i964{vt20R?=gAcy=ZQG;G;J;aTB(lFbM8;!?MkIa(-?R9
z^ytL3RC0QqQJ|RFI)z$2Lz8u=uKj_u=;_lF2nlwuqdG|#An*TW<Js?RwBM-md!q6J
zd>|M)q}n|gt%*FMxd!SZ)L7|&nnS64Xp6C2g0rA4m&n<eS}p<CD^3+jT9IU|l*FkL
zNh^`!DSoU(a`OB3ohg!>)3EEH7d#DmLEBZI7A^&Dt)#8JLCshL2FfL^TmreVwUTqb
zQ6!C(O2S+)JytFWJZqFlV{4@7I~%Emn^U|i;6z<CYGX+vNxF}->!IER&)8wvx!9^R
zw+IyqGSjSZbK(u;oSiOHznc`Q%5<kvpgX<=qpcGpY)4%9n}K`JQnP73jnFDn;r9(Z
zFiy?2-5K!d0iVn74zqY%BK6l!5=Wli11@FCC-8}W<m5Z1e9^X#soVG~K9f)666A_6
zvi-xnP{60H3dSGz5y!RSV0_A_tq#Vo__VShz7HI^!C)L@OC^xi)<~pw*IM6l2_KMx
zWNGjOnhZjC#a2D=*bJMg6>BoHCswcb;Yv#=#9qf91MEMfH+d~Pc#}5+U*BAJ3Dxcj
z1bl%52(Gs7Cn^0CKQQ2aw?g4psO~VO|J_2a__{R<>7aDeLZ*G)zaa=Q8vVmLDt~Kj
z4a+9KJo}keS94zIMqSikZA~)w;slfY>d>|tUC<t{QSSxJV<vNfxB^1Qwwh6xH}he*
z9-a(DWOA=hCnxuTeza<W`Z2wuW?*PDwaxx=@fQ^L@|6n|Jy6Wi6dh@soOi-|zQn$`
zr9o>r+Hkxf(Qu)`-sow(zwxO?qj9p)z4K=~5AXcb&IP;bcMa^AqE<4YhsfOlk#3{T
z3p%4MpohV2gf}33md7nQn9tEg1g8%Ns&$d>q6kBVt$w`0kKby-e+0!>3x*~<W;SXC
zIxKuYX3}FUIy%Gh_b8P?m--D&4mlshQQ2sflch$JEHL=H-NsY0$>1N!Mu^Z=ve825
zM!D5FG=Ud1<F|rj+3_ZPdy}z;O#OMcageBfwcAi&Tp^%}YrF6ZyH&$@Qz0Q;A9fpW
zE5a>Co1CaZrl-d(UaCUm^13Oc&Ii=|VUODt00>Hp?{UNAdeR7*WUsMb&P&k9oTcrT
zkL{OX+nsx4Z|8nlora><6xoX_bFl0O$Fw%tp+#g@;0V$V%Or3qVj>f!rG6qGmc3x5
z5C5_{W9-(aGRSK)NC?cgSZj?}N8SIRDno^d!{(yIw7D!XX%;2EG0PHH&GN+8W@Vzw
zd?0be+?+_6(y-ti7BU;Wnnzr>hUVXvrTL7v!vbMoQDDHmGy@2%nnuzLAT1UG%<KY%
z*lLx_VbCg{IQO}oivH^=l^<Fa>?l->;$VlU7^{M$Rdl>b#uj%<G0H5CjGzY?tAo&<
zqT9k8;Lv3D)O5V9q`}(y8^9q2JnR@zIyKp<)h$M$;$$jrZ8C-wxTaIukOIj}Aaz@a
zd}jV#^=~R#I^9~KA}mcjK|4L5GBZCzUG=9F?UZ#aG*L-7k-$K2!mUl}*H)K>)r6lw
z<2OV_TWPhWBI{cso!Kv&9A^Cqgpx}~hiDW^PJwh@URv4(3@GpjZVU1)k?;nI$mS6H
zMa^W1FY!)`PU(dTgkY1GR8n6PNy#3W<U^Ca*E<sc5MR;{iBmVHb<&-i)t4zakZE!-
z3jxY+wgkvQcf-B~N8(i^EYxjC#feu_PM6Li^#^1ki%evzR|rb0AM19~X5o%Wn_1ax
zj3_4CIiggoOj`sue|3$TcmJ@`3%>OZPW!}v76wgLupOQDkpj^U%48$g9gi16ra1VW
n7#9`sk`sOw#52lqG1!aWaHJbcq^&-mT)ii)3;6%x`!xPHW>H^O

delta 3588
zcmd^>`*Rc5702)0)h>G3Xow+_p?EQm*pzs7Xvhc;7-5@7!7S8OjK)KQNU%XGi=-*j
z5Kmhv6lWaBCJ?nFo482PK%%8t^DwESp`I8A603t#{m|(!%#gSw<KbmTP~ves1ozyP
zZfx=|RI>Me_IuAcd(YWDchwtO+8bJWx`@l$K0n`z&{xPvAiRVte2OZF0E0@ZHdn8y
zTrF*sHi{xbh`)%IqbK+1v&2z{u4ZnC$H71Duy*gT;=E?u)b+x{XR-0bR@LDVrZM4b
zuU0?t1^(R~j1Y$m2qOmZh(+Ug>bDr7lN<jUakXM+xR##?zc~C-xR=`+^ulG~v;Jy*
z3;!m^bg;}>zH|a9n9*2f05fSr^Z0J>2+MrHGH1w)^QM5ziB66YHZmjJ<X`BY$pquP
zS;8igC2SN4IJuaOGB7M*qcIrD*k~LEk&U|M;p9>_S_#8bel|J?<I`;PIt)%W8Y;%g
zayGgjh81j7n2(bcY_xbj_Li_N*2BKYwz4tyBR0+6V3EOY5Dn`MUc)}aVMD^uYq(;_
z7>u02Ik_#|ZZ5>Nai_U{Zjc+}Y<vkH9z0NSWS*n@#34MB4<9{b=B8~Lo*{?TLqCa}
zHQ~9l%PcK?l5c2nw3!pFt>WS~djp>;vxxIjosrunJinZmp%zdor>d?3&qRDDvL7^?
zeRZ3_u`};&eh9v$Xu?#3+B@_5bxHk=2{`g<7|$&Kk;_>gW{69_PHoPc$5G-R=`Tse
z*Vo6MM`~wY3xB{Uylf7id82R{XXz=kTrwW6$gH?=Ba7=ZYt^er;Ve{GktwHGli8qg
zmbaCexGeI(j2)uxY|a=#HKFyPi~48@{aqjHL+22RArwbQg+e%b)_TI*6?=EZpYcFd
zuwJ_*l|GzMZb@p0aSq>-fD+E(5lI=5v^$b>I3p<;DOqM2$VfJ8YwP6^$#z#osM)Jx
zIDof3kTt#sG%6{hQ{1%s5MWGF#w4&C7?o^uv=M3Go+K7P=z%dwwDMX;8n`b-Y(u!%
zQ)aRIY$(Q{BYd-7D1^@N8wLtwv2<XTY+K+QE|6OsPPL!d+~vi`QXe5(zWHR&Z=bg}
zIDAMr8DirT6X1KbUO2UR5FwF!$1eQ4``{4HXRKL;39&T=?(X9^aDid5-L2Z);M>9r
zuWu#~K$|)DNgTAl(%}}ZsdLC?ZSQbLN^0?3>oIr6nwn0OWA1R%zY2qPw{pRsEOe8F
zE1&q29d6~4KY7fpeC8KY{@vaw0h3^RPXb%zzNCWnsD2!igyox?$)#Z>Ej(0KxV>4m
zKSNP}WO9?aoOpGPTlii#3i6ZMGoU?U&DQF11hzIOPbL>%joa)#yW4jV!A2ARHCDr0
z0bu#@SFmsp$6K)4t}DmfaYa|!u^QEtm^=P1QAp6pf)QNw>?{w@r@y^&TY21bU5uj`
z?wRFDProt9rbpj!cvMj-^n{j!R+>pqhr#X>+Z~>Mn9mf!=?3`ZBw{mtaytE=R`8F!
zJA!|Pi@HDd;C|}@v0+6+O@p^#U&Ego&NW<VK#fZpw>2Ja>~A#es@~PQE4^#Z?(Pd5
zvyu&7^<|3~z}H2URldi4us9@agp@6U$1HqhQk|qR1bdz8WMY^AIjz_#jMoVj0pTpx
zcsXMdT&50Q7OvH4`LgYof?d{Za=J=;;1gNl4?gXoFT)C*J`Kq*e(cj2GNyfR1#P{9
z!tsDm(L`eXDj+19Gy|F2=F_aQ$O<p}v~geNXpM-3*}l+eZKa=-Vnd5VTkRKTYBS{2
z7L+MH;c(vEf}ja(GeUDf%shU=VfTRo9brA;fVmB%e;@d~nprMPF({L#nB@=5au5>f
zFv#8xvmCk$&8m$1yuw1W@WfVFl`=y%D+RLM_YP8K$)pq$Bt|arYjwn)m%R|?q_C_G
z1`_O{FDq=P0)praxt8#Ho%b7a2<<S2t>^L^^NvnOD59E~mEkRSe!4T8$$twA$twFq
zlEhGXdG;i?us)FhTmS%8k_AxU3Rxu!pfI`u&`kht#m|9la@Uu4I2_q$Wr`ME@V6&r
z?Gu0dd0D&QC;i;M(hui4t@3N1>GZzqJ~jr42ED3X^20W=c3X=PW??f}>S<q{6K8Fo
zB3AifneFTR9r?1}Q}tR>wy`y_CaubE_rb!e{BZM9C?rq)w+B}GmF(SBlCoHqdV#T(
zf=3Dke{8tQudLD^1LeG&vLTU$%}kgP2#vvO10lGYxCu6B?Yykq(YKEg{g{z1o8^pA
z_^>X8P`a$YmqF=aFoufj#&!U(w<6fo$uT1d;}S6qT1fo90J+4s!k9h|t4SG3z}Avp
zcrrlli$NwgC13VV?jRsQmC3$E7WG)xC%eP)YL86!BAA5w!~^;~d9EFhw`fkCLSnIM
zK#}r%ChuubrV+&y`X+U1!p4NYP&u*<!aE@A-y6`@`7?aSI)6=XHWVx`^80*d_QEy(
z1S~4i6LUMiOM;DP_)E-9T0ybOUdTXS@%yfam{~&Zbt0LBhu(<bwSHc9-n5|>V=@;a
zdETE8-ZEu(hVYR<QJ0th5C<Pk*%i=Jb_F11R{+XHQ?3sDkg_WPDObOw&rc?zt6h7w
z&jXOi=Yg88y-+(?;M6eW-E?|yvN{k&2>16B2r`u52Vhp>Da0tmDIBNp9t9W9c~w%V
zrm&X6AcgA`zNRn~q!eOuf%a24K;bnC0-Librm%p*A_~0}`Y2qa@F@kaAs6R4Loi1>
zsnkdTak(jmf`I~0Ax0ri;W&l&D7g4soJtDS6xPDe^K8ursdSyf*A(D4eAXs3EeHE4
z9H8(T1;LoJDW<T1!XgU26#4*`=}*B$Dt$`9Ysv+Bj>1j~jV2tvJ399lmjl_>I8^KW
z&b3ExjYG9w?MRanZu+4$vQ6O%<eH)~kZX#ZbFy;JqfHU^@_l+cbwf{KraNT8f2;a`
IIj&jwKSDiW)&Kwi

diff --git a/input.s b/input.s
index 7ec13e4..ab71a24 100644
--- a/input.s
+++ b/input.s
@@ -48,7 +48,7 @@ kbdScanRightArrow:
 	lda mapScrollPos
 	cmp #VISIBLETERRAINWIDTH-VISIBLETERRAINWINDOW
 	beq kbdScanDone
-	inc
+;	inc
 	inc
 	sta mapScrollRequested
 	rts
@@ -59,7 +59,7 @@ kbdScanLeftArrow:
 	lda mapScrollPos
 	beq kbdScanDone
 	dec
-	dec
+;	dec
 	sta mapScrollRequested
 	rts
 
diff --git a/macros.s b/macros.s
index 98f413a..8d77782 100644
--- a/macros.s
+++ b/macros.s
@@ -168,6 +168,15 @@ nobrk:
 	pla
 .endmacro
 
+.macro HARDBRK
+	pha
+	lda #1
+	sta $e1c029
+	pla
+	brk
+.endmacro
+
+
 ;;;;;;;;;;
 ; Stack Macros
 
diff --git a/terrain.s b/terrain.s
index 12d46b1..b4ecf1a 100644
--- a/terrain.s
+++ b/terrain.s
@@ -10,13 +10,14 @@ MAXTERRAINHEIGHT = 100	; In pixels
 COMPILEDTERRAINROW = TERRAINWIDTH/4+3	; In words, +2 to make room for clipping jump at end of row
 VISIBLETERRAINWIDTH = TERRAINWIDTH/4	; In words- width minus jump return padding
 VISIBLETERRAINWINDOW = 80				; In words
+MAXSPANSPERROW = 15
+
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; renderTerrain
 ;
 ; No stack operations permitted here!
 ;
-; Current implementation: Unknown cycles per row
 ; Trashes all registers
 ;
 renderTerrain:
@@ -61,6 +62,207 @@ renderTerrainDone:
 	rts
 
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; renderTerrainSpans:
+;
+;
+renderTerrainSpans:
+	pha
+	lda #MAXTERRAINHEIGHT-1;-7;-36
+
+renderTerrainSpansLoop:
+	sta PARAML1
+	jsr renderTerrainRowSpans
+	dec
+	bpl renderTerrainSpansLoop
+;brk
+	pla
+	rts
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; renderTerrainRowSpans:
+;
+; PARAML1 = Row index (bottom relative)
+;
+; Trashes SCRATCHL,SCRATCHL2,PARAML0
+;
+renderTerrainRowSpans:
+	SAVE_AXY
+
+	; Find row data
+	lda PARAML1
+	asl		; Shifts must match MAXSPANSPERROW*2 + 2
+	asl
+	asl
+	asl
+	asl
+	tay
+	lda terrainSpanData,y
+	sta SCRATCHL			; Track span color
+
+	; Find VRAM row
+	lda #200
+	sec
+	sbc PARAML1
+	tax
+	jsr enableFillMode
+	asl
+	tax
+	lda vramYOffset,x
+	clc
+	adc #$2000
+	tax
+	adc #160
+	sta PARAML0				; Watch for end of VRAM row
+
+	; Find span that intersects left logical edge
+	lda #0
+	clc
+
+renderTerrainRowSpansFindLeftLoop:
+	adc terrainSpanData+2,y
+	cmp leftScreenEdge
+	bpl renderTerrainRowSpansFoundLeft
+	iny
+	iny
+	pha
+	lda SCRATCHL
+	eor #%110000	; Toggle span color cache
+	sta SCRATCHL
+	pla
+	bra renderTerrainRowSpansFindLeftLoop
+
+renderTerrainRowSpansFoundLeft:
+	sec
+	sbc leftScreenEdge	; A now holds remainder of leftmost span
+						; and Y points to leftmost span
+
+renderTerrainRowSpansLoop:
+	sta SCRATCHL2
+
+	; Set fill mode byte for this span
+	lda SCRATCHL
+	sta VRAMBANK,x
+
+	; Advance to end of span
+	clc
+	txa
+	adc SCRATCHL2
+	cmp PARAML0
+	bpl renderTerrainRowSpansDone
+	tax
+
+	; Prepare for next span
+	iny
+	iny
+	lda SCRATCHL
+	eor #%110000	; Toggle span color cache
+	sta SCRATCHL
+
+	lda terrainSpanData+2,y
+	bra renderTerrainRowSpansLoop
+
+renderTerrainRowSpansDone:
+	RESTORE_AXY
+	rts
+
+
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; renderTerrainFillMode:
+;
+; Trashes all registers
+;
+renderTerrainFillMode:
+	jsr renderTerrainSpans
+	brk
+
+	SAVE_AXY
+	ldy #0
+	ldx #200-MAXTERRAINHEIGHT
+
+renderTerrainFillModeLoop:
+	jsr enableFillMode
+	sty PARAML1
+	jsr renderTerrainRowFillMode
+	inx
+	iny
+	cpy #MAXTERRAINHEIGHT
+	bmi renderTerrainFillModeLoop
+renderTerrainFillModeDone:
+brk
+	RESTORE_AXY
+	rts
+
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; renderTerrainRowFillMode:
+;
+; PARAML1 = Row index (top relative)
+;
+; Trashes PARAML1
+;
+renderTerrainRowFillMode:
+	SAVE_AXY
+	lda PARAML1
+	asl
+	tay
+	ldx vramYOffset,y
+
+	stz renderTerrainRowFillCurrent
+
+	sec
+	lda #MAXTERRAINHEIGHT
+	sbc PARAML1
+	sta PARAML1
+
+	ldy leftScreenEdge
+	sty renderTerrainRowFillColumn
+
+renderTerrainRowFillModeColumnLoop:
+	tya
+	asl
+	tay
+
+	lda terrainData,y
+	cmp PARAML1
+	bmi renderTerrainRowFillModeBlack
+
+	lda renderTerrainRowFillCurrent
+	cmp #$10
+	beq renderTerrainRowFillModeColumnLoopNext
+
+	lda #$10
+	sta renderTerrainRowFillCurrent
+	sta VRAM+(200-MAXTERRAINHEIGHT)*160,x
+
+renderTerrainRowFillModeColumnLoopNext:
+	inx
+	inc renderTerrainRowFillColumn
+	ldy renderTerrainRowFillColumn
+	cpy rightScreenEdge
+	bne renderTerrainRowFillModeColumnLoop
+
+renderTerrainRowFillModeDone:
+	RESTORE_AXY
+	rts
+
+renderTerrainRowFillModeBlack:
+	lda renderTerrainRowFillCurrent
+	cmp #$70
+	beq renderTerrainRowFillModeColumnLoopNext
+
+	lda #$70
+	sta renderTerrainRowFillCurrent
+	sta VRAM+(200-MAXTERRAINHEIGHT)*160,x
+	bra renderTerrainRowFillModeColumnLoopNext
+
+renderTerrainRowFillCurrent:
+	.word 0
+renderTerrainRowFillColumn:
+	.word 0
+
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; craterTerrain
 ;
@@ -246,6 +448,7 @@ compileTerrainLoop:
 	bra compileTerrainLoop
 
 compileTerrainDone:
+	jsr compileTerrainSpans
 	RESTORE_AY
 	rts
 
@@ -381,6 +584,129 @@ compileTerrainOpcode:
 
 
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; compileTerrainSpans:
+;
+;
+compileTerrainSpans:
+	pha
+	lda #0; MAXTERRAINHEIGHT-7;  0
+
+compileTerrainSpansLoop:
+	sta PARAML1
+	jsr compileTerrainSpansRow
+	lda PARAML1
+	inc
+	cmp #MAXTERRAINHEIGHT
+	bne compileTerrainSpansLoop
+
+	pla
+	rts
+
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; compileTerrainSpansRow:
+;
+; PARAML1 = Row index (bottom relative)
+;
+; Trashes SCRATCHL
+;
+compileTerrainSpansRow:
+	SAVE_AXY
+
+	lda PARAML1
+	asl		; Shifts must match MAXSPANSPERROW*2 + 2
+	asl
+	asl
+	asl
+	asl
+	clc
+	adc #terrainSpanData
+	sta SCRATCHL
+
+	ldy #0
+	ldx #TERRAINWIDTH-2
+
+	lda terrainData,x	; Figure out start value for row
+	cmp PARAML1
+	bcs compileTerrainSpansRowInitGreen
+
+compileTerrainSpansRowInitBlack:
+	lda #$0020		; First span is black
+	sta (SCRATCHL)	; Initialize the row
+	inc SCRATCHL
+	inc SCRATCHL
+	ldy #-1
+
+compileTerrainSpansRowBlackStart:
+	iny
+
+compileTerrainSpansRowBlackLoop:
+	lda terrainData,x
+	cmp PARAML1
+	bcs compileTerrainSpansBlackEnd
+	dex
+	dex
+	iny
+	cpx #-2
+	bne compileTerrainSpansRowBlackLoop
+
+compileTerrainSpansBlackEnd:
+BREAK
+	tya				; Store this span's length
+	sta (SCRATCHL)
+	inc SCRATCHL
+	inc SCRATCHL
+
+	dex				; Begin searching for next span
+	dex
+	cpx #0
+	bmi compileTerrainSpansRowDone
+	ldy #0
+	bra compileTerrainSpansRowGreenStart
+
+compileTerrainSpansRowDone:
+	RESTORE_AXY
+	rts
+
+compileTerrainSpansRowInitGreen:
+	lda #$0010		; First span is green
+	sta (SCRATCHL)	; Initialize the row
+	inc SCRATCHL
+	inc SCRATCHL
+	ldy #-1
+
+compileTerrainSpansRowGreenStart:
+	iny
+
+compileTerrainSpansRowGreenLoop:
+	lda terrainData,x
+	cmp PARAML1
+	bcc compileTerrainSpansGreenEnd
+	dex
+	dex
+	iny
+	cpx #-2
+	bne compileTerrainSpansRowGreenLoop
+
+compileTerrainSpansGreenEnd:
+;	iny
+
+;	lda #1								;
+;	sta breakpoint	;
+
+	tya				; Store this span's length
+	sta (SCRATCHL)
+	inc SCRATCHL
+	inc SCRATCHL
+
+	dex				; Begin searching for next span
+	dex
+	cpx #0
+	bmi compileTerrainSpansRowDone
+	ldy #0
+	bra compileTerrainSpansRowBlackStart
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; generateTerrain
 ;
@@ -446,3 +772,11 @@ clippedTerrainData:
 	.byte 0,0,0,0	; xx,jmp,addr
 	.endrepeat
 
+terrainSpanData:
+	.repeat MAXTERRAINHEIGHT
+		.word 0		; Start value (0=BG)
+		.repeat MAXSPANSPERROW
+		.word 0		; Length (in bytes)
+		.endrepeat
+	.endrepeat
+