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Battlefield 1942
· README FIRST
· Ai.con editing pt1
· Ai.con editing pt2
· Ai.con editing pt3

· Pathmapping pt1
· Pathmapping pt2

BF 42 Modding/Mapping: Pathmapping pt1

FOLLOW THE BLACK BRICK ROAD ... ?

sample files

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Welcome to Part One of the Ai Pathmapping Tutorial

In this Part of the Tutorial I will introduce you to Pathfinding Maps, what
they are, how they work and how to work with these files that are necessary
for Bot support.

We will be using the original Battlefield 1942 level Kursk in this tutorial
as an example of existing pathmaps.

There are many things that will not be covered in this Tutorial.

Firstly, this tutorial will only cover Land based maps that only use Cars,
Infantry, Tanks & Aircraft.

LANDING CRAFT and BOATS (ships) will NOT be covered.

Also, on occasions you may be required to do tasks that requires other software,
such as RFA Tools, Image Editors and Map Editors. If you are doing this tutorial,
you should already know how to do these tasks. It is not within the scope
of this tutorial to teach you other software unless it is a tool or technique
specific to Pathmapping.

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What are Pathmaps ?

Pathmaps are images that are used to describe to the Bots the location of
objects, steep slopes and anything in a level that could get the Bots in trouble
or “stuck.” This is done by literally drawing the Bots a diagram
of the map, using an image that is marked to show “Pathed Areas,”
that are open areas where the Bots may travel, and “Non-Pathed Areas”
the Bots Should avoid such as Walls or Cliffs. A simple two colour system
is used, with Black (Index#0) used for “Pathed Areas” and White
(Index#255) for “Non-pathed Area”

Without Pathmapping Bots would continually; try to walk/drive through walls,
try to walk/drive up slopes they cannot get up, walk/drive into holes/off
cliffs, get stuck on buildings & other Static Objects, drown/blow up when
they try to walk/drive across rivers, lakes or oceans ... phew.

In this case the picture speaks a million words, so we should have a look
at an Existing Pathmap. We will also need access to the files within the level
Kursk we will be working with. Open your favorite RFA tool and Extract Kursk.rfa
to the Folder that you use for Editor42 map editing.

To save confusion later, its not a bad idea to rename the Folder of the extracted
level from Kursk to Kursk_Pathmap.

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Importing Pathmaps

Pathmaps are packed in Dice's own format that we are not able to view with
our normal software. If you have software installed that has the RAW file
type already associated, such as Photoshop™, the program will attempt
to open the .RAW file when you double-click it, but as you may have already
discovered, the program will not display or open the file properly.

Luckily the format is similar to the .RAW Image format, and Rexman was able
to write an “Importer” that will unpack & convert Dice's .RAW
Pathmaps to 8-bit Greyscale .RAW images, that we can view and edit.

Browse to the Folder you extracted Kursk to, and look in the Pathfinding
folder.

15 files in all, and you should notice that there are three groups of 5 files
for each unit type. Each of these file contains information that is based
on the Level0Map Pathmapping files, and these are the files we will be having
a closer look at.

Browse to the Folder where you have unzipped Rexman's Ai Tools.

Import_Pathfind.exe is the first Ai Tool we will be using. It is a Command
Line Application that needs to be run from a Command Prompt (MS-Dos Window
in Win9x/Me) or from a .BAT (batch) File.

Included with this tutorial is Import_Level0Maps.bat, make a Copy of this
.BAT file in the same Folder as Import_Pathfind.exe. This batch file is setup
to Import most level0 Pathmaps that are in this Folder when run. If you are
curious which Pathmaps are setup for importing, or want to check that i haven't
slipped Format C: /Q into the file just right-click on the .bat and select
Edit.

Go back to where Kursk's Pathmaps were extracted and grab a Copy of the Car4Level0Map.raw
and browse back into your Ai_Bots folder and Paste the Car4Level0Map.raw
here.

Double-click Import_Level0Maps.bat to run the conversion process, and a new
file will be created, Car4Level0Map8bit.raw. Notice the same standard of file
naming is used, with the extra 8bit added to remind us the file is 8bit greyscale
.RAW

If you are using Photoshop™ or other software that can open 8-bit Greyscale
.RAWs, double-click on the new file, and if requested, make sure your settings
are the same as this.

IF YOU ARE NOT USING PHOTOSHOP

Don't Panic! If you don't have Photoshop or you prefer to use another Image
Editor that cannot open .RAW files, don't fret, there is a great utility called
FlyRawGui that will convert a 8-bit Greyscale .RAW image to a 8-bit Greyscale
.BMP (Windows Bitmap) images.

Use Convert RAW to BMP and browse to locate our Car4Level0Map8bit.raw

Open the file and it will be converted by the Program.

This File format is much friendlier, and can be edited in most Image editing
software ... except MS-Paint

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Viewing Pathmaps

Now that we have the Pathmap in a format we can use and view, Open it in
your favorite Image Editor and you should see something similar to this

(note: the following image is 50% of its original size)

O dear, does this look anything like Kursk ? For starters, like many other
things in Battlefield 1942 this is upside down Miss Jane, once we turn it
up the right way it might make more sense.

Photoshop

–=#=–

Similar in Corel Paint and other software

–=#=–

Once up the right way, look for features you may recognize. Near the bottom
is the Axis base, you can see the fence that goes around the House, and the
Barn off to the right.

The best way to see how a Pathmap interacts with the Terrain and Static Objects,
is to preview it, textured onto the map.

Rexman has another tool for us, exactly for this purpose. Ai_GenerateForLevel
will convert a level0 Pathmap to TX*.dds terrain tiles that we can then use
to view in a Map Editor or even In Game.

Go back to Kursk's extracted Pathmaps and grab another Copy of Car4Level0Map.raw.
Browse to the folder for Ai_GenerateForLevel and Paste the Pathmap there.

The _convertTolevelTexture.bat runs the several steps that are required,
and controls how our pathmap is converted. There are two settings in the .bat
file we may need to adjust from time to time depending on which Pathmap we
want to preview (car/infantry/tank) and the size of the map. Right-Click on
the .bat file, and select Edit, this will open the file in notepad for our
convenience.

The first setting relates to the Unit type of the Pathmap that we want to
preview.

@echo off

rem --- Do NOT put a .raw at the end of the filename here! ---

set tmpFileAI=Infantry1Level0Map

The tmpFileAI setting is a setting that allows to specify a variable that
will be used a few times within the batch file, so thankfully this allows
us to make one change instead of several. You need to change this to correspond
with the Pathmap that you are going to preview, in this case we want to preview
the Car Pathmap so we shall change the line to read.

set tmpFileAI=Car4Level0Map

And of course you need to change this line again to match your Pathmap if
you wish to view others such as the Tank0 or Infantry1 pathmap.

The next setting to look at is further down. This command runs a program
that will split our pathmap into tiles, you can see the tmpFileAI reference
that calls the setting we changed above. The setting we need to change here
is the value at the end. This refers to the number of Texture Segments &
needs to be set for the appropriate value for the of size of a map.

tgaSplit.exe %tmpFileAI%.tga 4

How do you know what setting you should use ? Well, in most cases there is
a very straight-forward answer, the following Table covers the Standard Size
maps.

Height Map Size	Std Worldsize	Std Texture Size (pixels)	Texture Tiles	Texture Segments
256	1024	4096	16 (4x4) (tx00x00 - tx03x03)	4
512	2048	8192	64 (8x8) (tx00x00 - tx07x07)	8
1024	4096	16384	256 (16x16) (tx00x00 - tx15x15)	16

Of course there are a few things that can throw a spanner in the works.

The most common being “missing” tiles – in some maps that
only use a portion of the terrain, the texture tile where no play occurs can
be removed to reduce the .RFA size – so this will stuff up counting them.
If the last tile in the series is “missing” (eg: tx15x15) that will
stuff up matching that to the table.

Something else you may have to work around is Texture offsets. This command
is used in Init/Terrain.con to “move” the textures, and you may
want to check this file to ensure that GeometryTemplate.texOffsetX and GeometryTemplate.texOffsetY
are BOTH set to 0.

Next is a not so common occurrence ... non-standard maps where the Worldsize
is not 4 times Heightmap Size as is the standard. Custom map makers may use
something like a 512/4096 Level (Heightmap/Worldsize) to increase the playing
area without increasing CPU requirements, or go the other way with a 256/512
level for greater detail in the terrain. Your best guide in these cases is
the Worldsize which you can check in Init/Terrain.con the setting to look
for is GeometryTemplate.worldSize.

Since there are only a few choices, if you don't get it right first go, at
least you will know which one it isn't. ; )

In this case we look at Kursk's Textures folder, and we note there is 16
Texture tiles, and also that the highest numbered Tile is tx03x03.dds

This matches with a Standard 1024 Worldsize level and the value we need is
4. Lucky for us the setting in the .bat file is already the right value, but
remember when doing other maps you may need to change this.

Save the changes to the .bat file, and then double-click it, to run the process.
It doesn't take long for the magic to manifest

Browse into the dds_terrain folder, and there you have your Pathmap on a
Map.

Cut all the .dds files, Browse to the Folder where Kursk is extracted, and
Paste the new .dds files into the Textures folder and Overwrite all the old
files.

You could repack the Kursk.rfa with these new textures, or even just make
a _00x.rfa style update, but for now, viewing the map in an Editor will do
fine. Coin Coin's Editor42 is used heavily in Pathmapping and its now time
to fire this editor up and open the level.

And first up you will see this, and remember Black is Pathed Area, and white
is Non-Pathed Area.

Now this explains thing much more clearly, note that around the Trees &
Rocks and up the sides of Hills the Areas are white. These are the Non-pathed
Areas that are used to keep the Bots from running into objects or going up
slopes that are too steep, and the flat area that is directly ahead is mostly
black, allowing Bots to roam free in this area.

Lets have a look at some other parts of the map.

Here we are at the Axis base we we're trying to look at earlier on the Pathmap,
again seeing the Pathmap around objects gives you a clearer indication of
how the pathmapping works.

Here we are looking straight down on the Sawmill Control Point. From here
you can clearly see the Pathmap image, how blocky it is in relation to the
buildings.

Note that there is a fair amount of area that is non-pathed or “Pathed
Out.” around Objects. Cars are the fastest moving ground vehicles in
Battlefield and this liberal non-pathed coverage around objects is to ensure
the Bots have plenty of space between themselves and Objects while on the
move. Tanks are slower and do not require as much space. Infantry is the slowest
ground unit, and they also have the ability to follow the pathmaps with the
highest accuracy of all the units and require no extra space to keep them
away from objects.

As always, its always best to see this difference firsthand. We will Repeat
the process with Kursk's Infantry1Level0Map.raw.

First, Import the Infantry1Level0Map.raw and then open the 8bit .raw in your
Image Editor/Viewer.

(note: the following image is 50% of its original size)

The first difference you should notice with the Infantry Pathmap is how much
more area is Black. Infantry units are able to get up much steeper slopes
then Cars, they can also move through much tighter spaces and closer to objects
then Cars. You will also notice that around Buildings and other objects the
details are much finer, whereas the Car's Pathmap had objects pretty much
blotted out.

Next, Use the Pathmap preview tool on the Infantry pathmap, and when you
are done Open our hacked up level again in Ed42. Remember, you will need to
change the tmpFileAI setting in the _convertTolevelTexture.bat file to match
the Infantry pathmap.

We're back at the same place we started with the Car Pathmap, and again you
will notice how much more area is Black.

Looking at the Axis Base again, the White pathing follows the objects very
closely. I bet your wondering why there are so many gaps in the pathing of
the fence, well ... nobody has ever said Dice's pathing was perfect ; )

Look closely at the Barn, you can just see a white edge on the left edge
of the building. This is how the Pathmaps for infantry should be, just the
right amount of Pathing. Too much Non-pathed area around the outside of an
object is an opportunity for a Bot to get “stuck” and once a Bot
is stuck in a non-pathed area, it will not be able to move until it dies and
respawns elsewhere, or is pushed into a Pathed Area. This can happen when
a Bot is thrown into a non-pathed area by an explosion or could be pushed
in by a passing vehicle. On the other side of the coin, if an object is not
completely pathed out, then it becomes an opportunity for the Bots to try
and walk through walls and/or other objects.

What other possibilities or problems do buildings pose to Infantry ? Lets
take a closer look at that Barn.

O dear ... a veritable minefield of obstacles. So how is it pathed ?

We can move the building in this copy of the map without doing any damage
to the original level, so lets move the Barn to get a better view of the pathing.
Use Ed42's object mode [Press F4] select the Barn, and use the mouse wheel
[or Page Up/Down] to move the Barn down into the ground until the floor sinks
below the terrain.

Hmmm ... its a bit rough in here, but you should get the idea. Notice that
the ladder is Pathed Out. As pathmaps are only Two Dimensional, it is not
possible to path the ground section AND the upper floor. To prevent the Bots
from running into the ladder & accidentally climbing it, only to get lost
on the upper floor, it is Pathed Out so the Bots avoid it entirely.

Ok, last stop in our rounds is the Sawmill again.

Just to hammer it in ... More Black, less White and the Pathing closely follows
the objects. Again take note of how blocky the Pathmap is compared to the
objects.

If you are making a Custom Level from scratch and you intend to add Bot support,
you should pay careful attention to building placement, especially if you
wish Bots to able to walk inside buildings. A well placed building is very
easy to Path as the dimensions of Dice's Objects match the “blockyness”
of the Pathmaps, whereas a poorly placed building could be very difficult
to path, and maybe even impossible as the doorways may not be able to match
up with the Pathmap's available pixels.

It is worth considering making a Pathmap or part of one, as a guide when
placing Buildings & other static objects in the early stages of your level
construction. This could form part of your planning, and would ensure accurate
placement of objects to the Pathmap, which will be very important for buildings
or tight locations that you expect the Bots to traverse.

Where you feel a building or is totally unimportant for Bot access, you can
be less stringent, and even Path out the building completely to save time.

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Making Pathmaps

Ok, staring at these things all day will get us no where, its time we made
our own Pathmap.

Open your favorite image editor and create a new image, your software should
give you a window for you set the new image's properties. So far we know that
we want an 8-bit Greyscale image, but what size should the Pathmap be ?

Pathmaps will always use the Worldsize as their resolution.

Kursk is a 1024 Worldsize level, and in case you didn't notice, the Pathmaps
we looked at were 1024 x 1024 pixels

Even in non-standard sized maps the Pathmaps are based on the Worldsize.
Eg: A 256 height map with a 512 Worldsize, instead of the “standard”
1024. The Pathmaps size will still be set by the Worldsize and should be 512
x 512 pixels

But we still don't know how big our Pathmaps should be ! Ok, ok .... we are
making our Pathmaps for Aberdeen, so we will need to know the worldsize of
this level. Browse to the folder where Aberdeen is extracted, and in the Init
Folder you will find Terrain.con.

Open this file up and look for the line.

GeometryTemplate.worldSize 1024

Bingo, there is the Worldsize plain as day, and will set our new Pathmap
image to 1024 x 1024 pixels. Change the appropriate settings for our new Pathmap,
and if possible set the Background or Paper Colour to Pure Black (Index 0)

Photoshop

–=#=–

Corel Paint

–=#=–

Paint Shop Pro

–=#=–

If your new image is anything other Pure Black, use a Bucket fill or a BIG
brush and ensure the whole image is totally and utterly Pure Black. So after
all that, if you don't have an image like this, you have done something wrong.

Now we are going to start generating a few files, so in wherever you like
to have your “working” files, make a new Folder (or tree) and we
shall save the Pathmap in there, away from our Levels folders.

To start with if you are using Photoshop, it needs to be noted that Photoshop
can be a pain at times, it has its little quirks and has a habit of asking
questions about settings that we couldn't give a flying frell about. One quirk
is easily worked around, whenever saving a 8bit .RAW from Photoshop choose
from the File menu, Save As ...

We will start by saving the Pathmap for the Cars, ensure the filename is
Car4Level0Map8bit.raw, and the Format is set to .RAW

Be aware of another Photoshop quirk that may add “copy” in the
filename to Save. Keep your eyes on it just in case.

Photoshop will then bug you ... Header: 0 is fine

And again, Photoshop will bug you, Printer settings we could not care less
about, just hit Ok.

Paint Shop Pro is also capable of saving directly to 8bit .RAW

Now use the Save As ... again, and save the same image as Infantry1Level0Map8bit.raw
and another Saved As ... Tank0Level0Map8bit.raw

IF YOU ARE NOT USING PHOTOSHOP

Flyrawgui comes to the rescue again! If you don't have Photoshop or you prefer
to use another Image Editor that cannot save directly to .RAW, you can save
your Pathmap as a 8bit .BMP (Windows Bitmap) and use FlyRawGui to convert
the 8bit .BMPs to 8bit .RAWs.

First save your new Pathmap Image as Car4Level0Map.bmp. If your software
has a Colour Depth setting in the Save dialog, make sure it is set to 8 Bit
Greyscale. Also make sure the image is saved Uncompressed if the option is
available.

Then use the Save As ... option, and save the same image as Infantry1Level0Map8bit.raw
and another Saved As ... Tank0Level0Map8bit.raw

Now, start FlyRawGui and select Convert BMP to RAW.

Browse to the Folder you have save the .BMP files, and Open Car4Level0Map8bit.bmp
to convert it to raw.

Repeat the conversion for Infantry1Level0Map8bit.bmp & Tank0Level0Map8bit.bmp

Don't worry about the .ACT files. You may recognise them as a Photoshop Colour
Table file, but for our purposes it is just luggage we have to work around.
You can keep deleting them if you like, but you may get sick of doing so.

From here onwards you may find it handy to sort the files in a Window by
Type as i have above, this groups the files together according to Filetype
and may make it easier to find the file you want when things start getting
crowded.

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Packing Pathmaps

We now have three 8bit Pathmaps, one for each unit class, but before they
are usable by Battlefield we need to pack them in the same format as Dice
has used. Again, its Rexman's tools to the rescue. Browse to your Ai_Tools
folder and open the 8bit folder.

This is where the Ai Pathmap Packer resides, and much like the Pathmap Previewer
requires several steps to do its job. Thankfully it can all be done with just
a double-click of _pack.bat

There is a two things we need to do, so the Pathmap packer is ready for use.

First, Edit _pack.bat and change the line,

set AIOUTDIR=..\

set AIOUTDIR=Pathfinding

Then save and close the file. You now need to make a new folder of the same
name.

Now when you double-click _pack.bat, 8bit .RAW Pathmaps that are in the same
folder, will be converted to Dice's RAW Format and all the files that are
required will be created in the Pathfinding folder we just created. Try it
now, there are some sample Pathmaps already here. Double-Click _pack.bat and
a Command Prompt window will appear briefly, now browse into the Pathfinding
folder.

Well this is good, we have 15 files again and seems our little test was successful.
Delete these test files and lets repeat the process with the new Pathmaps
we have created. Browse to your “working” folder, and Copy the three
8bit .RAW pathmaps your saved earlier.

Next, back to the Ai packer's Folder and Paste our Pathmaps here, and overwrite
the existing files.

Double-Click _pack.bat again, and then browse into the Pathfinding folder.

If all has gone well, we have 15 files again. Notice the files are quite
small, this is due to the Pathmaps being totally Black, and as your Pathmaps
increase in detail and complexity the filesize will also increase.

Now that we have our new Pathmaps converted to the type of files required
by Battlefield, we could quite happily use these in a level. They will not
do their job properly, since they are all Black and do not actually “Path
out” any objects at all, but they will allow the Coop mode to start.
This can be useful in getting a basic Ai package up and running as quickly
as possible, just ignore all the Bots headbutting walls.

Full Black pathmaps can also be useful in testing. If your Bots are not moving
at all, you can check your Pathmaps by temporarily replacing them with Black
Pathmaps, and if the Bots suddenly start moving, you now know that your Pathmaps
are suspect. If the Bots still do not move, you can at least remove bad pathmaps
from the list of possible problems.

- END OF PATH 1 -

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