From 3c43a0bc78d0ba582fcb4bef94decafff8088fb5 Mon Sep 17 00:00:00 2001
From: blondie7575 <qd@quinndunki.com>
Date: Wed, 9 Aug 2017 19:33:52 -0700
Subject: [PATCH] VBL experiments

---
 V2Make.scpt | Bin 2526 -> 2460 bytes
 graphics.s  |  84 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 gscats.2mg  | Bin 819264 -> 819264 bytes
 gscats.s    |  46 ++++++++++++++++++++++++----
 macros.s    |   1 +
 terrain.s   |   2 +-
 6 files changed, 126 insertions(+), 7 deletions(-)

diff --git a/V2Make.scpt b/V2Make.scpt
index 5da294f64385c78fb8336372324041c56ea07422..050b92c37e624b7e7145f208a416c33e339945e9 100644
GIT binary patch
delta 217
zcmca7JV$uLb5^D`9Fsq?dQD>E5K1pD$YEe&WJt`(EM@=#M!(6vY#Q7QTQ)!Bat|)Z
zDJ`Dd$Y#OGz-ajF(v>w!gC-wjlh5RFEGWpyOinDx%+D)k5Mbb7V7L(Dm=4q~2x4DZ
zD|!iJ6ax#$7zQQ=Ro}$q%)FBP;tT~37b|4VRtykJ^b!jS7#R2%#2C03+!=xy3K()2
dN*RhL7qV;0iz92$M^-P)z^Ko#`7%2<695t#Ka>Cf

delta 284
zcmbOud{218b5^Ez9Fsq?dQD>E5DG3gG-F_5WJt`(EM@=##tD;s*)(_<4bL=i2bZU&
zmKd5%ZeX+E01C`FpPdvj`5>EoJug%y-dN8-&zONhfPsU7;X;gKI?w<?5c_=gkrN=p
z7z98DF>vPJ1L7MDOp~uNFfrKrCMIX*mE;#^D0sM7g%+n46<aYBrdTn!<d^5=<R_*8
zxhNLExq68O1q=*)LJSfN+zi1C<qWAnSi)e)U^dy4UDHwrY?gjuiay*VeH4RWJg_;!
T42=2=45B~>ac-W-&dme>f>uoV

diff --git a/graphics.s b/graphics.s
index 7b09809..d23c9bb 100644
--- a/graphics.s
+++ b/graphics.s
@@ -30,6 +30,38 @@ colorFillLoop:
 	rts
 
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; bottomFill
+; Fills the bottom of the screen with a color (or two). Pretty fast, but not fastest possible
+; A 4:4:4:4 = Palette entries
+; X = Color to fill (doubled)
+;
+; Trashes Y
+
+bottomFill:
+	FASTGRAPHICS
+
+	lda #$9d00-1	; Point stack to end of VRAM
+	tcs
+
+	ldy #58
+
+bottomFillLoop:
+	; 80 PHXs, for 1 line
+	; We could do the entire screen with PHXs, but this is a
+	; balance between speed and super-verbose code
+	.byte $da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da
+	.byte $da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da
+	.byte $da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da
+	.byte $da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da,$da
+
+	dey
+	bne bottomFillLoop
+
+	SLOWGRAPHICS
+	rts
+
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; initSCBs
 ; Initialize all scanline control bytes
@@ -107,6 +139,58 @@ setPaletteLoop:
 	rts
 
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; Vertical blank checkers
+;
+
+; The Brutal Deluxe version, taken from LemminGS
+;
+nextVBL:
+	lda #75
+	pha
+nextVBL0:
+	lda $e0c02e
+	and #$7f
+	cmp 1,s
+	blt nextVBL0
+	cmp #100
+	bge nextVBL0
+	pla
+waitVBL:
+	lda $e0c018
+	bpl waitVBL
+	rts
+
+; The Apple version, taken from GS Tech Note 039
+;
+syncVBL:
+	BITS8
+syncVBL0:
+	lda $E0C02F
+    asl         ; VA is now in the Carry flag
+    lda $E0C02E
+    rol         ; Roll Carry into bit 0
+	cmp #200	; A now contains line number
+	bne syncVBL0
+	BITS16
+	rts
+
+; The old style //e version
+;
+vblSync:
+	BITS8
+
+waitVBLToFinish:
+	lda $E0C019
+	bmi waitVBLToFinish
+waitVBLToStart:
+	lda $E0C019
+	bpl waitVBLToStart
+
+	BITS16
+	rts
+
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; caches
 shadowRegister:
diff --git a/gscats.2mg b/gscats.2mg
index 724a57f36aba15afff15926d32bf7082178381b8..97ee4506e546f51c3ec3b2a888f65ab5e56f2eae 100644
GIT binary patch
delta 2560
zcma)*eM}Q)7{IR;@Or&|Lut8w9BnC7Csqal!A-!AxXG04592g0vdsZYW?(bZ7-PFg
z6$1!bo%3T0qNp|NiYeQ|NVbZ@fpPO|%Qm-6MzYK)$(k+xF^pr+``mj9ek3+|@ArJY
z@7?wCO9TrN!GfMQQVk1o7?r!2XPC1LO9ExMLOB>OPcv^->T<#>n|y(4Zqy(1B}P<d
z+Tl9jk0@24v<Sn98@Mi)OZ2M5BWf|qMSEGl!4h?;-t1+EtC?hen@bhsX(1^>c2fMF
z6F+669#!(9bfj;-bmT8{SlIsD#6(tGFI%;aRWK!YVoYL0uW#3fziqM<x>V%Izp}E(
zp*Jjd2K;cN<n_{0lK)8Zh=OVJsDc+5HpnoHj+xNy&Nk;Shj`Pd7%NJQv|Z*ROgjXz
zI!LZ?Dt|i!17ca*RW34dSm+#L!td^17XB#2&cDo&!RQrE8i`)zgq3Tb^qf*AToV$G
zmTy-Ai^3m=(u@zE7d{tS7>F!omc;TCBfbE0R?%^L_%)^{Sr@awdylV$KWKJhgd^=4
z!$X(;9`KWrH8J8JCs+MA6yW8U$Sy^wzA5bq9`0CuUwo!eHA~%HUs^g`r%2YOgzAGg
zN5$yFj|Z<Csb)fKr;+JS3t9U%s!M*iCY5@Qe4~)Hxj8sC$o6D?(W2g7%bnWtrTTf&
zSjUFg=4KcUj$)^qh2DXza8Gl7;B8;Xy6S!31aq=4KEoFXY~F1hN^~-pZoymB@U{GU
z{vAHR@8tLLoqUw<=g;%k_*?v4Ua#?J=4zH}Ue|2Z?AM&uT+rOmq-x#TO6@D!ZQ5?_
zkakRK&=u=m)@|3tbU*1*^nU#seT)8c{Y|}Kc)<`f^cwy&I0MEN#$Cp*jSAB|(<aj=
zrhiNY>2IaS({HDjWNgVelQG@A%>17Dy4jbxAv2Mwv8=Y7vW#1nT0gKRtqZe`*Iuhy
zt%j?Nd%Pb^iYA9N4qTId^q5CxQ?`+bsl$&dJUsG<U1VdX^!Vh|`#(58oZVuYCNZ5d
z1G)P^rV`tkv}~cYQVOK4XcaJ3wAv``lnzQKrAX-_+fH}5Fg@Mjrt}~i4|%1wmzHxW
z^C*3kGbm?LK1Df;GM{obrJr&RWdY^Wl!cT<$Ri&XOOH`Z%O#X^Da%N^aZeehjeF)%
zK12B|<$TI=%1W}WrmGUunyv+u3n>>%?L{f%tHRu(RQ#AE3U?e#q1|vtYpNXT52nds
z$D!$RSl-IYVMB{b4trWSIcx}V^p<e&VO}oxv})wAA*2bwLoiI4P$4W4s)d(?SB3S$
zW?_f0PdFy@3WLHA!cE~n!DRE<%55ucjkXrsaod3Hy6vvbW}jzYV-MK7?C0#a>;^}P
zW36MSBkuUs!8wba>zsR?Upa3(bH!ESF7d4RujtRN%RZ9*bGF&_qO0BYjf;0zx!c@<
zi*BQ5h3AmxH&0$pLr!1LH19I+LGK^lqTHt3?{ahUHs+nrbNGmwtfZy{Ifeg@7A8lN
zic`uDBrq1hLuFa+pCwfu%%`0Dn2`tX@z^mOl+0v_p<pHw%mflMF$FV`U?vjGL<*#h
zW+K5%B$$Z=Gm&5>63j%p$Tl<+31%X}Odv56Q!o<=W+K5%B$$Z=Gm&5>63j$`nMg1b
z31%X}OeC0z1T&FfCKAj<f|)>KCZ=E}63j$`naDEIMl+FMCKAj<f|*D#6A5M_E6FxA
z6A5M_!A#_0sZGqp9L<y>G*b@2Od1k1<tms-Lt-WkiJ3GcX3AA!CXI=i@&uT9Z$d*R
y;uXqrMSSc;h2iMf3B|U;{vCz=3Rp^5(_p2*N`;jMYdS0zmI@a4Sz*7LAN(JoSN0MB

delta 2381
zcmaKrdu&s66vuz<w(h?A+`6sz_Ho;FkAh-1H^VlN)eI3KVJJaFqxgrJLyZ_?M1!`$
z6-KaZ;}WBYvN$1>tPY)tZYmZCWIQyBnn(zVW56FOA$1r`K$+)v?yud(!`uA&`JQvn
zJ#E^2(y`iftoFd#0{grmDJ*Yt5^{uaG#Isr@#tW)spKsq7t~gDgqCdK$HN1m^ca7r
z3*HZhlcQYRlq5t=@gD~Q>R+6?Q|Qld>JPly!KEg+%!EE4TA<ILt>NZgA0X*5+coV*
zhg_54j<=G`6<JPXxY(t#>xaXs43|0I*huTMv`!jGVuFi}5-vsvvG({~b6O#+A6EzJ
z(_@Jfe3EoQ7<dkflRO{pf^b-EN}S@8le?7O5u)|PmubJo3mqqTI+!}i>m#XCyq4%}
z(d=7_%KvA}C+$Q1vy`Qkea)MUQDIMeW8?7=lF5&^$9^AIQ@8F^R;@|4k~r7vAbU)4
z*U&m)?nPI|XcHDsPRemtXJ_ovQSN|zutV6?ChXtvmGCgV@hlhTIy+%FHja1paBy$C
ztC&<1ffTTppdH)di@s1DcddReG)eXi^@l>y=o>w*k#sK^{bLOwtHm{9oA{ErUfd`q
z#P`L$;uqo(@h9<ucva*jk5nr?Bt0#?CUr~urK8e0>4xMsH<_O>Z!mvkK4iXV7A#@Q
zW0t68pXEo(zm|}7rM1I4XgzN&wmoQj-IlVA+sdN$W%kYXwEddB-tn^IQ^zI8?4sw3
z`im|X)fB&4JX}nii=17~)6PK2izP!PrqUIqeWh1QTgu)o`>kxgYj4|`r7Hw@&mzaE
zFfC1wEJx4i7h7}NYQ|%9V&?Ge8n=$z<|+DMss8op)~O5jYkzJn%F|iQ=wvKGezvpB
zh+{5_<p~#dmnURKh0)FEVe~Tk7*$3;V}LP;Yj;&pM0zT)8|kTJtYWNY3^C4PoXvO_
z<K2vN81G>WGuANHGTzHr$5_vJAM)Jpx%$^?pfK!cz^-9OBV!ZeJjVHq_cJbFY-Wrw
zKET*Q*ZTVw>S)QQ|0dKe1^6e@r1fsiXLq&Ucs@Qy+v+=}skSNC?u{2t%Umw22_ZY)
zy-m!;gp`eA33E1f@3LfLbHW;3ArMk0H_8!tvHXbqq}(RIBFE%y@`rLtJ}8gM=jFd;
zNeL(o%5r6`(xL2DzE(~vR~4tb-o4Vj-u;35JNE^*;HmLE?%C++_x$3?^M<`oc@y4m
zy_dbJ?@`}o-#5MqUr2pM-KqYpTK!A>o&IC~g22MSroc!vAeJvH-%)<1+#hTYejfZM
zxTr#_7^|35`DW$!mENj#RY$5ytEry`-A^6a5`IY5n4YFJXS8oB=vb6WpS`Ab>7ASF
z8GG+Aa`R{0aZDf7Cbl~A;B&xJ@DmAsBEe4}^%F}M1^S5uKat=k68uDhpGfc%34S8M
zPbBz>1V52MTnm0eg?=KzPbBz>1V54BCldTbf}cq66A6AI!A~Uki3C59;3pFNM1r44
z@DmAsBEe4}^%Khm3iJ~Rej>q7B>0I0Kat=k68uDhpGfc%34S75=vwM0g8Hck>ZhL2
z&upZAvP}KVwZYF^20wEd{LGGnpDa>8vl0Ack@}hKf}bpcpAZKl#%4ob-LPTsN-|;_
nY&8}d-mV+o3=KF&IC*gL;S|6z!6}5p!QtTuU)Bwa(y{*lZY_t0

diff --git a/gscats.s b/gscats.s
index 7a9218f..38801ea 100644
--- a/gscats.s
+++ b/gscats.s
@@ -32,9 +32,35 @@ mainBank2:
 	jsr generateTerrain
 
 mainGameLoop:
-	ldy mapScrollPos
-;	jsr renderTerrainColumns
 
+	jsr syncVBL
+
+;	ldx #$2222
+;	jsr bottomFill
+
+;	ldx #$1111
+;	jsr bottomFill
+
+	lda scrollV
+	bmi negV
+
+	clc
+	lda mapScrollPos
+	adc scrollV
+	cmp #TERRAINWIDTH/4-80
+	beq reverseScroll
+	sta mapScrollPos
+	bra render
+
+negV:
+	clc
+	lda mapScrollPos
+	adc scrollV
+	beq reverseScroll
+	sta mapScrollPos
+
+render:
+	tay
 	jsr renderTerrain
 
 	jsr kbdScan
@@ -46,7 +72,15 @@ mainGameLoop:
 	CLASSICVIDEO
 	jml (proDOSLongJump)
 
+reverseScroll:
+	lda scrollV
+	eor #$ffff
+	inc
+	sta scrollV
+	jmp mainGameLoop
 
+scrollV:
+	.word 1
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; kbdScan
@@ -60,7 +94,7 @@ kbdScan:
 
 kbdScanLoop:
 	lda KBD
-	bpl kbdScanLoop
+	bpl kbdScanDone
 	sta KBDSTROBE
 
 	cmp #(8 + $80)
@@ -71,9 +105,9 @@ kbdScanLoop:
 
 	cmp #(32 + $80)
 	beq kbdScanSpace
-	NATIVE
 
 kbdScanDone:
+	NATIVE
 	rts
 
 kbdScanLeftArrow:
@@ -105,9 +139,9 @@ kbdScanSpace:
 
 
 basePalette:
-	.word $0800,$0080,$0000,$000F,$0000,$0000,$0000,$0000,$0000,$0000,$0000,$0000,$0000,$0000,$0000,$0000
+	.word $0800,$0080,$0000,$000F,$0FFF,$0000,$0000,$0000,$0000,$0000,$0000,$0000,$0000,$0000,$0000,$0000
 mapScrollPos:	; 4-pixel columns distance from right terrain edge
-	.word 80
+	.word 79
 quitRequested:
 	.word $0000
 
diff --git a/macros.s b/macros.s
index 93153ab..2b12de4 100644
--- a/macros.s
+++ b/macros.s
@@ -117,6 +117,7 @@
 	sta PARAM24
 .endmacro
 
+
 ;;;;;;;;;;
 ; Stack Macros
 
diff --git a/terrain.s b/terrain.s
index 83afeb8..02905ca 100644
--- a/terrain.s
+++ b/terrain.s
@@ -6,7 +6,7 @@
 
 
 TERRAINWIDTH = 640		; In pixels
-MAXTERRAINHEIGHT = 100	; In pixels
+MAXTERRAINHEIGHT = 20	; In pixels
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; renderTerrain