WADParser.py

## WADParser.py
#!/usr/bin/env python3

import struct
import re

class Wad(object):
    """Encapsulates the data found inside a WAD file"""

    def __init__(self, wadFile):
        """Each WAD files contains definitions for global attributes as well as map level attributes"""
        self.levels = []
        self.wad_format = 'DOOM' #Assume DOOM format unless 'BEHAVIOR'
        with open(wadFile, "rb") as f:
            header_size = 12
            self.wad_type = f.read(4)[0]
            self.num_lumps = struct.unpack("<I", f.read(4))[0]
            data = f.read(struct.unpack("<I", f.read(4))[0] - header_size)

            current_level = Level(None) #The first few records of a WAD are not associated with a level

            lump = f.read(16) #Each offset is is part of a packet 16 bytes
            while len(lump) == 16:
                filepos = struct.unpack("<I", lump[0:4])[0] - header_size
                size = struct.unpack("<I", lump[4:8])[0]
                name = lump[8:16].decode('UTF-8').rstrip('\0')
                print(name)
                if(re.match('E\dM\d|MAP\d\d', name)):
                    #Level nodes are named things like E1M1 or MAP01
                    if(current_level.is_valid()):
                        self.levels.append(current_level)

                    current_level = Level(name)
                elif name == 'BEHAVIOR':
                    #This node only appears in Hexen formated WADs
                    self.wad_format = 'HEXEN'
                else:
                    current_level.lumps[name] = data[filepos:filepos+size]

                lump = f.read(16)
            if(current_level.is_valid()):
                self.levels.append(current_level)

        for level in self.levels:
            level.load(self.wad_format)

class Level(object):
    """Represents a level inside a WAD which is a collection of lumps"""
    def __init__(self, name):
        self.name = name
        self.lumps = dict()
        self.vertices = []
        self.lower_left = None
        self.upper_right = None
        self.shift = None
        self.lines = []

    def is_valid(self):
        return self.name is not None and 'VERTEXES' in self.lumps and 'LINEDEFS' in self.lumps

    def normalize(self, point, padding=5):
        return (self.shift[0]+point[0]+padding,self.shift[1]+point[1]+padding)

    def load(self, wad_format):
        for vertex in packets_of_size(4, self.lumps['VERTEXES']):
            x,y = struct.unpack('<hh', vertex[0:4])
            self.vertices.append((x,y))

        self.lower_left = (min((v[0] for v in self.vertices)), min((v[1] for v in self.vertices)))
        self.upper_right = (max((v[0] for v in self.vertices)), max((v[1] for v in self.vertices)))

        self.shift = (0-self.lower_left[0],0-self.lower_left[1])

        packet_size = 16 if wad_format is 'HEXEN' else 14
        for data in packets_of_size(packet_size, self.lumps['LINEDEFS']):
            self.lines.append(Line(data))

    def save_svg(self):
        """ Scale the drawing to fit inside a 1024x1024 canvas (iPhones don't like really large SVGs even if they have the same detail) """
        import svgwrite
        view_box_size = self.normalize(self.upper_right, 10)
        if view_box_size[0] > view_box_size[1]:
            canvas_size = (1024, int(1024*(float(view_box_size[1])/view_box_size[0])))
        else:
            canvas_size = (int(1024*(float(view_box_size[0])/view_box_size[1])), 1024)

        dwg = svgwrite.Drawing(self.name+'.svg', profile='tiny', size=canvas_size , viewBox=('0 0 %d %d' % view_box_size))
        for line in self.lines:
            a = self.normalize(self.vertices[line.a])
            b = self.normalize(self.vertices[line.b])
            if line.is_one_sided():
                dwg.add(dwg.line(a, b, stroke='#333', stroke_width=10))
            else:
                dwg.add(dwg.line(a, b, stroke='#999', stroke_width=3))

        dwg.save()

class Line(object):
    """Represents a Linedef inside a WAD"""
    def __init__(self,data):
        self.a, self.b = struct.unpack('<hh', data[0:4])
        self.left_side, self.right_side = struct.unpack('<hh', data[-4:])

    def is_one_sided(self):
        return self.left_side == -1 or self.right_side == -1

def packets_of_size(n, data):
    size = len(data)
    index = 0
    while index < size:
        yield data[index : index+n]
        index = index + n
    return

if __name__ == "__main__":
    import sys

    if len(sys.argv) > 1:
        wad = Wad(sys.argv[1])
        for level in wad.levels:
            level.save_svg()
    else:
        print('You need to pass a WAD file as the only argument')