🚀 go-pugleaf

This document describes how to create Mission files to use homemade
Descent levels.
 
1.  What a mission is
 
A mission is a series of Descent levels that can be played as a game.  A
mission consists of up to 30 levels, and can include normal and secret
levels.  A mission can be available either for anarchy games only (an
"Anarchy mission"), or for both single-player and Anarchy games (a "Normal
mission").  A mission is described by a simple text file, called a Mission
File.  This MSN file is necessary for Descent to recognize the levels
properly.
 
 
2.  Why you should use missions
 
Missions give Descent a way to keep track of new levels.  Descent
routines that reference a level, such as saved games & multiplayer games,
also store the mission name, and need the MSN file to work correctly with
user-created missions.
 
We strongly advise against replacing Descent's built-in levels with your
own.  Doing so destroys the integrity of the build-in mission, and can
cause crashes when restoring games or playing multiplayer games.
 
PLEASE include a MSN mission file with any new levels you create.
This way, people can play multiplayer games against each other and know
they are playing the same levels.
 
 
3.  How missions are specified
 
A mission is defined by a mission file, which is a plain text file with
the extension "MSN."  (The default mission, "Descent: First Strike," is
built into the executable and does not have a corresponding mission
file.)  Whenever the player starts a new game (either single player or
multiplayer), Descent scans the disk for MSN files, and reads the name and
mission type.  All the missions found, along with the built-in mission,
will be presented to the user when starting a game.  (Anarchy-only 
missions will not be offered in single-player games.)
 
 
4.  How to create a mission file
 
A mission file contains the following information:  the mission name
(which you make up), the type of mission (normal or anarchy), the
number of levels, and the names of the level files.  Optionally, 
you can specify the number of secret levels and the names of those
levels.
 
Here is a sample mission file.  This file describes the 5-level "Total
Chaos" mission that is included with registered/commercial Descent.
The ';' character specifies a comment; the rest of the line is ignored.
 
---- START FILE: CHAOS.MSN ----
name = Total Chaos	;any name you want
type = anarchy		;can be "normal" or "anarchy"
num_levels = 5		;number of normal levels
chaos1.rdl		;level filename 1
chaos2.rdl		;level filename 2
chaos3.rdl		;level filename 3
chaos4.rdl		;level filename 4
chaos5.rdl		;level filename 5
---- END FILE ----
 
Missions also support secret levels.  Secret levels are listed after
the normal levels, and for each secret level you must also specify which 
normal level contains the exit to secret level.  Note that to get to the 
secret level, there must be a door with the correct trigger type set.
 
Here's a file for a mission with three normal levels and one secret
level.  The secret level is accessed from level 2.
 
---- START FILE: MATT.MSN ----
name = Matt's Missin        ;any name you want
type = normal                ;can be "normal" or "anarchy"
num_levels = 3               ;number of normal levels
matt1.rdl                    ;level filename 1
matt2.rdl                    ;level filename 2
matt3.rdl                    ;level filename 3
num_secrets = 1              ;number of secret levels
secret1.rdl,2                ;get to secret level from level 2
---- END FILE ----
 
 
5.  HOG files, and how to organize your data
 
A HOG file is a very simple library file, which contains level (RDL) 
files as well as other data.  The format for the HOG file is specified
in the official level specs.
 
Each mission can (but does not have to) have its own HOG file.  This
mission-specific file has the same name as the MSN file, with the 
extension "HOG."  Thus the "Total Chaos" mission stores its level files
in CHAOS.HOG.
 
When Descent is looking for a file, it searches in this order:
 
 1. In the Descent directory
 2. In the Mission-specific HOG
 3. In the default hog (DESCENT.HOG)
 
If you are distributing a mission with several levels, PLEASE combine
the RDL files into a HOG file.  That way, you can distribute just the
MSN and HOG files.  It isn't a bad idea to make a HOG for 1-level
missions as well.
 
 
6.  Other cool things you can do
 
6.1.  You can create missions that include the normal Descent levels.
 
The normal Descent levels have the names LEVEL01.RDL, LEVEL02.RDL, etc.,
up to level 27.  The secret levels are LEVELS1.RDL, LEVELS2.RDL, etc.
By specifying these filenames in your custom mission file, you can 
incorporate the First Strike and Chaos levels into your own mission.
 
6.2.  You can add new music to your mission.
 
Each level loads a music file with the name GAMEnn.HMP, where 'nn' is
the 2-digit level number.  By creating your own HMP files and putting
them in your mission-specific HOG file, you can have unique music for
your levels.  The HMP files are a format used by the Sound Operating
System developed by Human Machines Interfaces.
 
 
Matt Toschlog
Parallax Software


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