-Change: extractwsa.py: correctly handle "multipart" WSA files

tools/extractwsa.py

@@ -8,20 +8,18 @@
 from westwood_codecs import *
 from save_pictures import *
 
-palette = None
-
 def load_palette(filename):
-	global palette
 	with open(filename, 'rb') as pal_file:
-		palette = ''.join(map(lambda c: chr((ord(c) << 2) + (ord(c) >> 6)), list(pal_file.read())))
+		return ''.join(map(lambda c: chr((ord(c) << 2) + (ord(c) >> 6)), list(pal_file.read())))
 
 def xor_strings(s1, s2):
 	dest = ''
 	for i in range(min(len(s1),len(s2))):
 		dest += chr(ord(s1[i]) ^ ord(s2[i]))
 	return dest
 
-def extract_wsa(filename):
+# frame : set to last frame of previous WSA for "continuation" WSA
+def extract_wsa(filename, palette = None, frame = None):
 	with open(filename, 'rb') as wsa_file:
 		wsa = wsa_file.read()
 		(frames, width, height, req_buffer_size, has_palette) = unpack_from('<HHHHH', wsa)
@@ -38,22 +36,36 @@ def extract_wsa(filename):
 		print ' ', map(lambda e : len(e), datablocks)
 		pictures = map(decode_format40, datablocks)
 		print ' ', map(lambda e : len(e), pictures)
-		pixels = chr(0) * (width * height)
 		frames = []
-		for i in range(len(pictures)):
+		if len(pictures[0]) > 0:
+			pixels = pictures[0]
+			frames.append(pixels)
+		else:
+			if frame is None:
+				pixels = chr(0) * (width * height)
+				print 'no first frame provided'
+			else:
+				# continue from last frame of previous WSA
+				pixels = frame
+				if len(pixels) != (width * height):
+					print 'frame size mismatch : ', len(pixels), width * height
+		for i in range(1, len(pictures)):
 			pbm_filename = '%s_%02d.pbm' % (filename, i)
 			if len(pictures[i]) > 0:
 				pixels = xor_strings(pixels, pictures[i])
 				#save_pbm(pbm_filename, width, height, pixels, palette)
 				frames.append(pixels)
 		save_flc(filename + '.flc', width, height, frames, palette)
+		return frames[-1]
 
 if len(sys.argv) <= 1:
 	print "usage : %s [-p palette.PAL] file.WSA" % sys.argv[0]
 else:
 	args = sys.argv[1:]
+	frame = None
+	palette = None
 	if args[0] == '-p':
-		load_palette(args[1])
+		palette = load_palette(args[1])
 		args = args[2:]
 	for filename in args:
-		extract_wsa(filename)
+		frame = extract_wsa(filename, palette, frame)