compressed title image, loads faster

4 files changed, 234 insertions, 8 deletions

diff --git a/Makefile b/Makefile
index a515ea0..56a81b4 100644
--- a/Makefile
+++ b/Makefile
@@ -84,8 +84,8 @@ taipan.atr: all
 
 # The game binary is a multi-part binary load file. This rule
 # depends on all the pieces, and just concatenates them.
-$(XEX): taimain.xex taifont.xex newtitle.xex titledata.xex
-	cat titledata.xex newtitle.xex taifont.xex taimain.xex > $(XEX)
+$(XEX): taimain.xex taifont.xex newtitle.xex comptitle.xex
+	cat comptitle.xex newtitle.xex taifont.xex taimain.xex > $(XEX)
 
 # Bitmap data for the title screen, 256x184 = 47104 pixels, 8 bits
 # per pixel, or 5888 bytes. Displayed in ANTIC mode F (aka GR.8),
@@ -96,6 +96,11 @@ $(XEX): taimain.xex taifont.xex newtitle.xex titledata.xex
 titledata.xex: newtitle.pl newtitle.png
 	perl newtitle.pl > titledata.xex
 
+# compressed title, for faster loading.
+comptitle.xex: titledata.xex titlecomp.pl comptitle.s.in
+	perl titlecomp.pl 151 < titledata.xex
+	cl65 -o comptitle.xex -t none comptitle.s
+
 # Init segment that loads after the title screen data. It sets up
 # a custom display list and sets the GTIA for narrow playfield,
 # then waits for a keypress. Afterwards, it restores the OS's
diff --git a/comptitle.s.in b/comptitle.s.in
new file mode 100644
index 0000000..7862b3d
--- /dev/null
+++ b/comptitle.s.in
@@ -0,0 +1,116 @@
+
+; cl65 -o comptitle.xex -t none comptitle.s
+
+; comptitle.s.in is used by titlecomp.pl, to generate comptitle.s.
+; __VARIABLE__ stuff is filled in by titlecomp.pl, q.v.
+; DON'T bother to edit comptitle.s (edit the .in file instead)!
+
+ .include "atari.inc"
+
+ ; size of uncompressed image, in bytes (but, needs to be
+ ; a multiple of $100).
+;imgsize = __SIZE__
+imgsize = $1700
+
+ ; these both need to be page-aligned. destination also needs
+ ; to be aligned on a 4K boundary.
+start = $2000
+destination = $9000
+
+srcptr = FR0
+dstptr = FR0+2
+pagecount = FR0+4
+tmp = FR0+5
+
+ .word $ffff
+ .word start
+ .word end-1
+
+ .org start
+
+compdata:
+ .incbin "comptitle.dat"
+
+; table runs __FIRSTCODE__ to __LASTCODE__
+table:
+ __TABLE__
+
+ ; decompression code starts here
+init:
+ lda #>imgsize
+ sta pagecount
+ lda #>compdata
+ sta srcptr+1
+ lda #>destination
+ sta dstptr+1
+ lda #0
+ sta srcptr
+ sta dstptr
+ tay
+
+copyloop:
+ lda (srcptr),y
+ bpl storebyte  ; 0-127 always represent themselves
+ cmp #__LASTCODE__+1
+ bcs storebyte  ; anything above the last code represents itself
+ sta tmp
+ sec
+ sbc #__FIRSTCODE__
+ bcc notcode    ; anything below the 1st code represents itself
+ tax
+ lda table,x
+ beq notcode
+
+ ; got a zero-run code. A = number of bytes of zeroes to store.
+ jmp storezerorun
+
+notcode:
+ lda tmp
+
+storebyte:
+ sty tmp
+ ldy #0
+ sta (dstptr),y
+ jsr incdest
+ beq done
+nohi:
+ ldy tmp
+
+storedone:
+ iny
+ bne copyloop
+ inc srcptr+1
+ bne copyloop ; always branch (since srcptr never wraps around to 0)
+
+done:
+ rts
+
+storezerorun:
+ sty tmp
+ tay
+ dey
+ lda #0
+szloop:
+ sta (dstptr),y
+ jsr incdest
+ beq done
+nohi2:
+ dey
+ bpl szloop
+
+ ldy tmp
+ jmp storedone
+
+incdest:
+ inc dstptr
+ bne iddone
+ inc dstptr+1
+ dec pagecount
+iddone:
+ rts
+
+end:
+ .word INITAD
+ .word INITAD+1
+ .word init
+
diff --git a/taipan.c b/taipan.c
index 4792896..af755e4 100644
--- a/taipan.c
+++ b/taipan.c
@@ -43,11 +43,12 @@ extern unsigned char agetc(void);
 /* wrapper for agetc(): lowercases letters */
 extern unsigned char lcgetc(void);
 
-/* wrapper for agetc(): returns only numbers, enter, backspace */
+/* wrapper for agetc(): returns only numbers, a, enter, backspace */
 extern unsigned char numgetc(void);
 
 /* wrapper for agetc(): returns only y or n.
-	dflt is 'y' 'n' to set the default answer, or 0 for no default. */
+	dflt is 'y' or 'n' to set the default answer if the user presses Enter,
+	or 0 for no default (waits until user presses either y or n) */
 extern unsigned char __fastcall__ yngetc(char dflt);
 
 /* sleep for j jiffies (no PAL adjustment at the moment) */
@@ -130,7 +131,7 @@ void cblank(unsigned char count) {
 	gotoxy(oldx, oldy);
 }
 
-/* conio doesn't back up the cursor if you cputc(BS), it
+/* conio doesn't back up the cursor if you cputc(BKSP), it
 	prints the graphics character instead. Could use putchar(),
 	but using stdio links a bunch of extra support code. So: */
 /* TODO: rewrite in asm */
@@ -139,6 +140,9 @@ void backspace() {
 	cblank(1);
 }
 
+/* get an inventory item, return its index into items[].
+	if allow_all is true, allows '*', which is used for
+	'throw cargo' in sea_battle. */
 unsigned char get_item(unsigned char allow_all) {
 	unsigned char i;
 	for(;;) {
@@ -201,7 +205,7 @@ char    *months[] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun",
 char    *st[] = { "Critical", "  Poor", "  Fair",
                   "  Good", " Prime", "Perfect" };
 
-unsigned long   cash         = 0,
+unsigned long cash         = 0,
         bank         = 0,
         debt         = 0,
         booty        = 0,
@@ -894,6 +898,9 @@ int sea_battle(int id, int num_ships) {
          timed_getch(TMOUT_3S);
          flushinp();
 
+			/* screen flash doesn't change the hue bit of
+				COLOR2 register, since we now support changing
+				it on the title screen. */
 			for(i = 0; i < 3; i++) {
 				unsigned char color = PEEK(710) & 0xf0;
 				POKE(710, color | 0x0c);
@@ -953,9 +960,11 @@ int sea_battle(int id, int num_ships) {
 			// 0 or 1: the intended result would just be 0 or 1 anyway.
 
 			newdamage = ((ed * i * id)/2) + (i / 2);
+			if(newdamage <= 0) newdamage = 1; // how the hell could this happen?
 			if(newdamage > 1)
 				newdamage = randi() % newdamage;
 			damage += newdamage;
+			if(damage > capacity) damage = capacity; /* just in case */
 
 #ifdef DAMAGE_TEST
 			gotoxy(0, 23);
@@ -971,7 +980,6 @@ int sea_battle(int id, int num_ships) {
 			cgetc();
 #endif
 
-			if(damage > capacity) damage = capacity; /* just in case */
          if((id == GENERIC) && (randi()%20 == 0)) {
             return 2;
          }
@@ -2743,7 +2751,9 @@ int main(void) {
       {
          // float fine = ((cash / 1.8) * ((float) randi() / RAND_MAX)) + 1;
 			// the 1.8 is now a 2
-			unsigned long fine = randclamp(cash >> 1) + 1;
+			unsigned long fine = 0;
+			if(cash > 0)
+				fine = randclamp(cash >> 1) + 1;
 
          hold += hold_[0];
          hold_[0] = 0;
diff --git a/titlecomp.pl b/titlecomp.pl
new file mode 100644
index 0000000..2e17a92
--- /dev/null
+++ b/titlecomp.pl
@@ -0,0 +1,95 @@
+#!/usr/bin/perl -w
+
+$datasize = 0x1700;
+
+use bytes;
+
+# skip xex header
+read(STDIN, our $junk, 6);
+
+read(STDIN, $data, $datasize);
+
+for(split //, $data) {
+	$got{ord($_)}++;
+}
+
+$firstcode = shift || 128; # must be >=128
+for($firstcode..255) {
+	push @available_codes, $_ unless $got{$_};
+}
+print scalar keys %got, " unique byte values\n";
+print scalar @available_codes . " available run codes >= $firstcode\n";
+
+sub allocate_code {
+	if(!@available_codes) {
+		die "out of run codes!\n";
+	}
+
+	return shift @available_codes;
+}
+
+# add a $ff to the end, to force the last run to be written
+# if the file ends in a run. Remove it afterwards.
+$run = 0;
+$output = "";
+for(split //, $data . chr(0xff)) {
+	if($_ eq "\0") {
+		if($run) {
+			$run++;
+		} else {
+			$run = 1;
+		}
+	} else {
+		if($run > 1) {
+			if($runlengths{$run}) {
+				$output .= chr($runlengths{$run});
+			} else {
+				my $code = allocate_code();
+				$runlengths{$run} = $code;
+				$used_codes{$code} = $run;
+				$output .= chr($code);
+				$lastcode = $code;
+			}
+		} elsif($run == 1) {
+			$output .= "\0";
+		}
+		$run = 0;
+		$output .= $_;
+	}
+}
+
+# remove the $ff we added above.
+substr($output, -1) = "";
+
+open $out, ">comptitle.dat";
+print $out $output;
+close $out;
+
+$pct = int(length($output) * 1000 / length($data))/ 10;
+print "1st code $firstcode, last $lastcode, table size " . ($lastcode - $firstcode + 1) . "\n";
+print length($output) . " bytes compressed data, $pct% ratio\n";
+print "used " . keys(%runlengths) . " codes\n";
+
+
+for($firstcode..$lastcode) {
+	$table .= " .byte ";
+	if(exists($used_codes{$_})) {
+		$table .= '$' . sprintf("%02x", $used_codes{$_}) . " ; " . sprintf("%02x", $_);
+	} else {
+		$table .= "\$00 ; SELF";
+	}
+	$table .= "\n";
+}
+
+open $in, "<comptitle.s.in" or die $!;
+open $out, ">comptitle.s" or die $!;
+
+while(<$in>) {
+	s/__TABLE__/$table/;
+	s/__FIRSTCODE__/$firstcode/g;
+	s/__LASTCODE__/$lastcode/g;
+	print $out $_;
+}
+
+close $in;
+close $out;