renderlevels.pl, first pass at a level-renderer

2 files changed, 122 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
index 2591a01..ade14ca 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,4 @@ tmp.lbl
 1.pl
 2.pl
 atari???.png
+level??.png
diff --git a/renderlevels.pl b/renderlevels.pl
new file mode 100644
index 0000000..8d0140c
--- /dev/null
+++ b/renderlevels.pl
@@ -0,0 +1,121 @@
+#!/usr/bin/perl -w
+
+# render jumpman junior levels to PNG files, by reading the graphics
+# and map data from the ROM image. input is 'jumpman.rom' in the current
+# directory, output is level01.png through level12.png in the current dir.
+
+# this code won't win any beauty contests, but it does work.
+
+$verbose = 0; # 0 = quiet, 2 = very chatty
+
+use Image::Magick;
+use bytes;
+
+sub getbyte {
+	return ord(substr($rom, $_[0], 1));
+}
+
+sub getword {
+	return getbyte($_[0]) + 256 * getbyte($_[0] + 1);
+}
+
+sub getdelta {
+	return $_[0] < 128 ? ($_[0]) : ($_[0] - 256);
+}
+
+# placeholder colors. ideally we'd have a full Atari palette, and read
+# the color register values from the level desc in the rom.
+%palette = (
+		0 => [ 0x0000, 0x0000, 0x0000 ],  # background
+		1 => [ 0x0000, 0x0000, 0x8000 ],  # girders, up-ropes
+		2 => [ 0x0000, 0x8000, 0x0000 ],  # ladders, down-ropes
+		3 => [ 0x8000, 0x0000, 0x8000 ],  # bombs
+);
+
+sub draw {
+	my ($img, $shape, $dx, $dy, $xpos, $ypos, $copies) = @_;
+	warn sprintf "drawing shape %04x at $xpos, $ypos, $copies copies, delta ($dx, $dy)\n", $shape if $verbose > 1;
+	while($copies--) {
+		my $width;
+		my $addr = $shape;
+		while(($width = getbyte($addr++)) != 0xff) {
+			my $xoffs = getdelta(getbyte($addr++));
+			my $yoffs = getdelta(getbyte($addr++));
+			for(my $p = 0; $p < $width; $p++) {
+				my $pixel = getbyte($addr++);
+				my $color = $palette{$pixel};
+				$img->SetPixel(x => $xpos + $xoffs + $p, y => $ypos + $yoffs, color => $color);
+			}
+		}
+		$xpos += $dx;
+		$ypos += $dy;
+	}
+}
+
+open ROM, "<jumpmanjr.rom" or die $!;
+if((read ROM, $rom, 0x4000, 0x8000) != 0x4000) {
+	die "couldn't read ROM\n";
+}
+
+for my $level (1..12) {
+	my $img = Image::Magick->new;
+	$img->Set(size => '160x100');
+	$img->ReadImage('canvas:black');
+
+	my $desc = 0xa000 + 0x40 * ($level - 1) + 22;
+	my $mapaddr = getword($desc);
+
+	if($level == 9) {
+		# show real map for blackout, not the blank one.
+		# the bombs are still invisible though.
+		$mapaddr = 0xb000;
+	}
+
+	warn sprintf("level $level, map pointer at \$%04x, points to \$%04x\n", $desc, $mapaddr) if $verbose;
+
+	# don't initialize these, we want warnings if some level
+	# tries to draw without selecting shape and direction.
+	my $shape;
+	my $copies;
+	my $dx;
+	my $dy;
+	my $xpos;
+	my $ypos;
+
+	while(1) {
+		my $opcode = getbyte($mapaddr);
+		if($opcode eq 0xff) {
+			warn sprintf "  got end opcode (\$ff) at \$%04x\n", $mapaddr if $verbose > 1;
+			last;
+		}
+
+		my $operand1 = getbyte($mapaddr + 1);
+		my $operand2 = getbyte($mapaddr + 2);
+		my $opword = getword($mapaddr + 1);
+		warn sprintf "%04x:   %02x   %02x %02x\n", $mapaddr, $opcode, $operand1, $operand2 if $verbose > 1;
+		$mapaddr += 3;
+
+		if($opcode == 0xfe) {
+			$shape = $opword;
+			warn sprintf "set shape %04x\n", $shape if $verbose > 1;
+		} elsif($opcode == 0xfd) {
+			$dx = getdelta($operand1);
+			$dy = getdelta($operand2);
+			warn "set delta X $dx, delta Y $dy\n" if $verbose > 1;
+		} elsif($opcode == 0xfc) {
+			$mapaddr = $opword;
+			next;
+		} else {
+			$xpos = $opcode;
+			$ypos = $operand1;
+			$copies = $operand2;
+			draw($img, $shape, $dx, $dy, $xpos, $ypos, $copies);
+		}
+	}
+
+	my $pngfile = sprintf("level%02d.png", $level);
+	open my $out, ">$pngfile";
+	$img->Write(file => $out, filename => $pngfile);
+	close $out;
+	warn "wrote $pngfile\n";
+}