More reliable checks for the destruction of 3D rasterizer's line table on aux zp.

Platform/Apple/virtual/src/core/mem.s

@@ -325,6 +325,7 @@ loMemBegin: !pseudopc $800 {
 	jmp __internalErr
 _fixedRTS:
 	rts			; fixed place to find RTS, for setting V flag
+_diskOpCt !byte 0		; count of disk ops since last render
 
 __aux_dispatch:
 	sec
@@ -411,6 +412,7 @@ _jbrk	jmp $1111		; self-modified by init
 ; Clear carry to call opendir, set carry to call rdwrpart
 ; On return, A contains status (for opendir only)
 callProRWTS:
+	inc _diskOpCt
 	; Copy the parameters to aux zero page
 	ldx #$F
 -	sta clrAuxZP

Platform/Apple/virtual/src/include/mem.i

@@ -513,6 +513,7 @@ _crout      = _prY+3
 _waitKey    = _crout+3
 _internalErr = _waitKey+3
 fixedRTS    = _internalErr+3
+diskOpCt    = fixedRTS+1
 
 ; Debug macros
 !macro safeBell {

Platform/Apple/virtual/src/marks/marks.s

@@ -14,6 +14,7 @@
 !convtab "../include/hiBitAscii.ct"
 
 ; Other equates
+!source "../include/mem.i"
 !source "../include/prorwts.i"
 
 target  = $3	; len 1
@@ -256,6 +257,7 @@ _writeMarks: !zone
 	sec
 	; fall through to final ProRWTS command
 callProRWTS:
+	inc diskOpCt
 	stx sizelo
 	sty sizehi
 	sta reqcmd

Platform/Apple/virtual/src/raycast/render.s

@@ -1959,9 +1959,19 @@ pl_render: !zone
 	bne +
 	lda $2001
 	cmp $4001
+	bne +
+	lda $2C00
+	cmp $4C00
+	bne +
+	lda $2C01
+	cmp $4C01
+	bne +
+	lda diskOpCt		; check if any disk ops (ProRWTS can use aux zp)
 	beq ++
-+	jsr copyScreen		; if it was, restore by copying hgr1 to hgr2
-	jsr makeLines
++	jsr copyScreen		; restore by copying hgr1 to hgr2
+	jsr makeLines		; and regenerate line pointers on aux zp
+	lda #0
+	sta diskOpCt
 ++	jmp renderFrame		; then go ahead and render
 
 ;-------------------------------------------------------------------------------