Changes between Initial Version and Version 1 of reading_baldurs_gate_binary_files

Timestamp:

Aug 18, 2006, 5:18:57 PM (18 years ago)

Author:

riklaunim@…

Comment:

Page Creation

reading_baldurs_gate_binary_files

@@ +1 @@
+Python has “batteries included” and as we all know Django is written in this language. Python has struct module (http://docs.python.org/lib/module-struct.html) which can do many interesting things. 
+
+If you played in Baldurs Gate, Icewind Dale or Planescape Torment then this mini tutorial may be quite interesting for you – we will read data from a binary file – Baldurs Gate II CHR file containing data abut players character. Before we continue check out:
+
+[http://forums.pocketplane.net/index.php/topic,21741.0.html pocketplane.net forums] – How to read data from infinity engine files
+
+[http://iesdp.gibberlings3.net/ieformats/ieformats.htm IE File Formats list] – specification of Infinity Engine files, we will use CHR v2
+
+
+'''Requirements''': you need a working django, can be development server. We will create one view and one template. 
+
+- Create a view and hook it up in the urls.py:
+{{{
+from django.shortcuts import render_to_response
+import struct
+
+def view_char(request):
+        file = open('media/Mag.chr', 'rb')
+        try:
+                text = file.read()
+        finally:
+                file.close()
+        print text[0x0000:0x0000+4]
+        print text[0x0004:0x0004+4]
+        print text[0x0008:0x0008+32]
+        return render_to_response('char.html')
+}}}
+Where '''('media/Mag.chr')''' is a path to the CHR file. Create '''char.html''' template with some pointless text and open the view in the browser. In the terminal where the development server is running you should see:
+{{{
+CHR
+V2.0
+Daria
+}}}
+We have just read the basic data, and reading more isn't any problem (only problem is to specify the locations). Looking at CHR V2 and CRE V1 specification we can read more data:
+{{{
+from django.shortcuts import render_to_response
+import struct
+
+def view_char(request):
+        file = open('media/Mag.chr', 'rb')
+        try:
+                text = file.read()
+        finally:
+                file.close()
+        char = {}
+        if str(text[0x0000:0x0000+4]) == 'CHR ':
+                char['name'] = str(text[0x0008:0x0008+32])
+                a = struct.unpack('i', text[0x0028:0x0028+4]) # offset to CRE "file"
+                a = 0x0000+a[0]
+                if str(text[a:a+4]) == 'CRE ' and str(text[a+4:a+8]) == 'V1.0':
+                        char['xp'] = str(struct.unpack('i', text[a+0x0018:a+0x0018+4])[0])
+                        char['hp'] = str(struct.unpack('h', text[a+0x0024:a+0x0024+2])[0])
+                        char['pic'] = str(text[a+0x0034:a+0x0034+8])
+                        char['str'] = str(struct.unpack('b', text[a+0x0238:a+0x0238+1])[0]) #str
+                        char['int'] = str(struct.unpack('b', text[a+0x023a:a+0x023a+1])[0]) #int
+                        char['wis'] = str(struct.unpack('b', text[a+0x023b:a+0x023b+1])[0]) #wis
+                        char['dex'] = str(struct.unpack('b', text[a+0x023c:a+0x023c+1])[0]) #dex
+                        char['con'] = str(struct.unpack('b', text[a+0x023d:a+0x023d+1])[0]) #con
+                        char['char'] = str(struct.unpack('b', text[a+0x023e:a+0x023e+1])[0]) #char
+        # better error checking/reporting would be nice
+        return render_to_response('char.html', {'char': char})
+}}}
+And the template:
+{{{
+<h1>{{ char.name }}</h1>
+<b>Hit Points</b>: {{ char.hp }}<br>
+<b>Experience Points</b>: {{ char.xp }}<br>
+<b>Strenght</b>: {{ char.str }}<br>
+<b>Dexterity</b>: {{ char.dex }}<br>
+<b>Constitution</b>: {{ char.com }}<br>
+<b>Inteligence</b>: {{ char.int }}<br>
+<b>Wisdom</b>: {{ char.wis }}<br>
+<b>Charisma</b>: {{ char.char }}
+}}}
+
+
+'''The results''':
+
+- [http://www.fotosik.pl/pokaz_obrazek/1caaa78b57139425.html Screenshot 1]
+
+- [http://www.fotosik.pl/pokaz_obrazek/d83c09db39cc1a70.html Screenshot 2]
+
+You can read and write to any binary file with python – you just need the specification which shows where the data is located and what type it is :) Note that there aren't available specifications for most proprietary file formats.