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Crimson Fields - an overview

Crimson Fields

What is Crimson Fields ?

Crimson Fields is an Open Source 'clone' of an early turn based 'Hex' map DOS computer war-game by Blue Byte Software known as "Battle Isle". This was a mechanised unit (tank warfare type) battle field level game with a basic campaign capability. It was shipped on floppy disc !

It was very advanced** for its time, supporting 'hot seat' (players making alternate turns on single computer) mode, 'network' mode (even across the Internet !) or using a 'play by email' approach. There was even a basic 'AI' allowing single person play = and all this on a single floppy disc !

However the authors (Blue Byte) wandered off into space chasing the 'future war' genre with a nonsense-based 'alien planet ground conflict' approach (as if some-one with space capability couldn't simply drop rocks on their opponents - see, for example, extinction of the dinosaurs) game, so by the time a version of Battle Isle was released for Windows it had already departed the Earth, disappeared into space and was never seen again :-(

**Note. Of course it's got no fancy graphics or clever soundtrack (although you can add your own sound track if you wish) and even some of the basic 'assumptions' are rather odd - such as some basic mistakes in deciding what is 'terrain' (which can't be attacked) or what is a 'unit' (which can be attacked and destroyed) = bridges, for example, are terrain (which prevents some of the more obvious defensive strategies).

The inclusion of trenches (as terrain) and lack of any sort of 'missile' (not even unguided rockets are supported) places the game in the WW1 (1915) time-line - however the huge variety of armoured vehicles (and lack of soft-skinned ones) plus the inclusion of armoured hovercraft suggests the 1960's !!

Fortunately, at least one fan refused to let the original game concept die, and, after quite a lot of coding, this resulted in Crimson Fields !

Since Crimson Fields is Open Source, it's perfectly legal for me to host the Windows installer build crimson-051-win32.exe (the source can be found on Source Forge). I can even make changes (so long as I make available the new source), and that means almost all the 'annoyances' can be fixed = see my later pages

What about other Open Source hex based games ?

Whilst other Open Source games do exist - for example Advanced Strategic Command (ASC) - they are all on their way to becoming bloated monsters (ASC, for example, is 37 Mb !). They also have other drawbacks (ASC, for example, uses truly horrible colours for both armies as well as the terrain)

The big advantage of Crimson Fields is that it's source code is actually small enough to read through (and understand) in it's entirety - remember this game fitted on ONE FLOPPY DISC (the game .exe was about 350kb) ! This means it is (relatively) easy for one person to make changes !

Can I use my Battle Isle maps in Crimson Fields ?

Yes - it is possible to convert any of the Battle Isle / Battle Isle Data Disk 1 & 2 / Battle Isle 'History Line' (WW1) maps (and thus any you have saved or created yourself) into Crimson Fields format, HOWEVER the required conversion tool, bi2cf.exe, is not included in the Windows 0.5.1 build :-(

Crimson Fields source code is provided under the GNU Open Source licence so you can compile the bi2cf.exe tool from the crimson-0.5.1.tar.gz source code (it is written in C++).

For those not wanting to go through the same painful learning experience as I did, you can downloaded bi2cf.exe here, HOWEVER this comes with 'no warranty' = what works fine for me, on my Windows XP (32bit) computer, may well fail for you on your VISTA / Windows 7 / Windows 8/10 64bit 'games machine'

For those unable to find or read their original Battle Isle map data floppy disk, however, there is another problem. Ubisoft (the current owners of Blue Byte) have not made the maps available for download - and since they no longer offer the game for sale, there is no 'legal' way for you to replace a failed (or lost) floppy.

You can, of course, obtain copies of the Battle Isle games from one of the many sites hosting 'abandon-ware', such as 'myabandonware' or 'games.fileheaven', however doing so would, of course, be copyright violation, even if you already 'paid'** for the game (so you might want to avoid sites that demand you 'Register')
** If you read your licence you will discover that you have paid for the 'right' to play the game from the original 'media' and no other. Whilst you may be permitted to copy the game from the floppy it was supplied on to a CD or your hard disk to make a single 'back-up', that does not entitle you to play the game directly from that backup - to stay legal you have to 'restore' the back-up onto a floppy disc first.
Needless to say, such ludicrous restrictions are widely ignored and do nothing but bring the whole Copyright Law into disrepute
WARNING - no matter what the level of contempt you feel toward Copyright Law, unless you want to hand over control of your computer to some criminal 'Bot Net', NEVER, EVER, 'run' a 'kracked' game, no matter what !!

Hopefully, I don't have to point out the dangers of downloading anything from a site that invites you to 'buy' pirated games .. (nor mention what happens when you give your credit/debit card or PayPal details to these criminals)

Can I create my own maps ?

Yes, indeed - either totally 'from scratch' (with the optional assistance of the 'random terrain' builder) or by modifying an existing map.

The map edit tool, 'CoMET' takes a bit of getting used to - 'left click' will immediately replace the existing terrain 'tile' with whatever new tile is currently 'selected' from the 'terrain palette' (or adds the unit currently selected from the 'unit palette') - which is fine until you try to select a building or unit by 'left clicking' on it :-(

The only real problem with CoMET is it's inability to edit multi-paragraph text 'messages'. Fortunately a 'workaround' exists = you can 'export' the map as a '.scr' file, use any text edit tool (such as Notepad++) to make changes and then 'convert' this back into .lev format using the (included) 'cfed' tool (CoMET itself can not 'import' the .scr (it can only open the .lev file))

To give you an idea of what is possible, here's one of my own campaign maps, The Train Game (this one is based on the supplied 'Radio Silence' map)

Using 'cfed'

The '.lev' maps are held in a non-text 'binary' format. The CoMET tool can 'export' a .lev map into a text based '.src' file, however it has no 'import' capability. Assuming you 'saved' as {name}.src to the C:\Program Files\Crimson Fields\levels folder, to convert {name}.src into {name}.lev your must use the 'cfed' tool from a Command Window (aka 'DOS box'). First 'cd' to the C:\Program Files\CrimsonFields\levels folder and then type as follows:-

cfed {name}.src --tiles ..\default.tiles --units ..\default.units
where 'default.tiles' & 'default.units' are the 'compiled' terrain tile and unit definition files. These are in the folder above the '\levels' folder (which is where the .lev maps are held and where CoMET 'exports' the .src), hence the '..\' prefix

NOTE it's possible to modify the icons and parameters of the terrain tiles and units, however you then have to recompile (mktileset / mkunitset) the definition files and re-build (cfed) the maps from 'source' to implement the changes (see later)

The .src (map file) format definition

The map source definitions used to be hosted on "digipedia" (a SRC file format web site), however that page no longer exists. Fortunately, I grabbed a copy of the format text which can be found here :-

For my own (rather better, I would suggest) explanation, go to my Crimson Fields map file definition page

Modifying the Tiles & Units

Unfortunately there is no way to directly edit the terrain tile & unit definition files. Instead you edit the 'source' (CFUnits.bmp & default.usrc and CFTiles.bmp & default.tsrc files) and then recompile them (see my Next page for How to Build from the source code)

In the /tools sub-folder of the build, you will find mktileset.exe and mkunitset.exe. To discover how to use these to recompile the units and tiles sets, check out the end of the Makefile.am script.

Pre-complied First World War tile and unit sets can be downloaded from the bebits repository.

If you have problems with downloading, I host a copy (right click and 'save link as' to download the .zip here).

To use the WW1 set, they should be placed in the C:\Program Files\CrimsonFields\ root (and not in \share as per the ReadMe)

Note - in CoMET, I found problems with the new map 'auto terrain generator' when using the WW1 tile & unit set. There are no problems editing (or 'manually creating') WW1 maps

How does it play ?

When you play against the computer 'AI', try to remember this is 'only' a floppy disc sized (< 1 Mb) game :-)

Whilst the 'AI' can perform as well as some over-bloated multi-Gb games, it is actually very easy to 'fool', especially as all it will ever do is attack (even when it's units start off in pre-prepared defensive positions) and minimal 'threat recognition' capability (see A10 re: attacking mines)
So the most obvious trick is to retreat your forces for the first move or two .. the AI will then send it's fastest units forward at 'full speed' to attack you, leaving all it's slower units behind.
Even on the smallest map, the AI's Air units will always outrun it's AA Tanks, which in turn outruns other Tanks, all of which leave their Artillery support behind whilst the slowest unit (AA 'guns') are left sitting on the 'start line'.
As a result, you can focus on disposing of it's Air Units, Scouts and AA Tanks before having to fight against it's Medium & Heavy Tanks & finally wipe out it's Artillery and AA Guns. Don;t make the same mistake (or the AI will happily wipe you out in th same way :-) )

When building new units in 'Factories', the AI always builds the 'most expensive' it can afford. Usually the Factory starts with some decent level of resources (perhaps 200 or so), so the AI builds Artillery (or whatever other most expensive unit is available). Once it's used up all the start resources, most maps have a very low 'resource replenishment' rate = so the AI usually spends the rest of the game building Infantry units as soon as possible.

The AI fails to specifically protect itself from enemy infantry advancing to capture one of it's own bases (and is easily distracted from capturing a neutral base). It is slightly better at capturing enemy bases, however it seems to 'forget' to move out any units it has just 'captured' in a neutral base, leaving them inside until you (the enemy) gets close(r)

The AI typically attacks the nearest enemy unit - and keeps on attacking until it wins or is destroyed. So it's actually quite a surprise when the AI 'retreats' and sends a 'damaged' unit back to base for repair :-)

The AI is especially 'careless' with it's Air Units - whilst it is sensible to attack eg. your Medium Tanks (which have no AA capability) it will do so even when they are protected by a dozen nearby AA Guns & AA Tanks.

Be aware that there is an 'attack bonus'. When two units of equal 'strength' fight on the same terrain, it's either a draw (with either no losses or equal losses) or, more often, the attacker wins (so the AI's tendency to attack everything it can is actually quite a reasonable strategy)

On the other hand, some terrain (hills, trenches) can make a big difference in defense - so don't abandon a good position just to get your blow in first

When you attack a single enemy with multiple units, combat is resolved 'one step at a time', in the order you chose to attack. Each attack is resolved in turn with all the other attacking units acting as support. Losses from the first combat resolution are carried forward to the next

What this means in practice is that you need to be very, very, careful indeed in choosing the attack 'sequence'
Typically, you should start with your artillery (and other ranged units) first, then attack with your 'most powerful' unit and so on.
Losses inflicted on an enemy unit 'early' in an attack sequence can result in it being destroyed by a weak unit attacking last, whilst that same weak unit would itself be destroyed if attacking first !
Note that 'acting in support' means that Artillery causes more losses when it is 'concentrated' - i.e. if attacking with 1 Artillery causes 1 loss, attacking with 2 Artillery 'at the same time' could cause 3 (rather than 2) losses.
Note that it is not necessary to attack immediately after moving .. you can move all your units forward into contact, then select them in any order to set the attack order sequence.
NB. Since a unit gains effectiveness in attack (or defence) when supported on it's flanks (+10% ea) and to it's rear (+5%). This makes it worthwhile bringing up weak units on the flank & rear, even if you choose not to use them to actually attack. Of course, only units that 'could have' attacked (or defended) against the enemy actually add support to their friends - so you get no support from a unit (eg transport plane) that has with no attack capability against that enemy)

Units gain 'experience' from killing the enemy - this makes quite a big difference to their (future) combat effectiveness

In Crimson Fields, a unit only gains experience when that unit itself directly inflicts losses on the enemy.
So, when the enemy is weak and surrounded, you should attack with the unit(s) you want to gain experience first (if the enemy is destroyed early in the combat resolution, later attackers won't even get a chance to fight, let alone cause losses)

No unit is allowed to 'move through' (or over, or under) another, not even air units or submarines.

So you make sure to move your 'fast' units first (so they can end their turn 'out of the way' of the others yet to move)
When there are many units on the map - or when some 'bottle neck' exists (see later) - the AI inevitably ends up in a 'traffic jam'.
Moving 'in speed order' is especially vital on maps with roads, bridges and 'mountain passes', where it's all too easy to find half your army 'stuck' behind some slow moving Artillery / AA Gun unit.
Note that Artillery can't move and fire in the same turn, so getting them 'off the road' and out of the way of other units before combat is even more vital.
Air units should be played as a sort of 'super hover-craft' :-) If you try to apply 'real' aircraft tactics you will be 'caught' and killed. Yes, you can move air units through a 'gap' and attack the enemy rear, however on the enemy turn you can guarantee the AI will close the 'gap' leaving your air unit 'trapped' behind enemy lines where it will inevitably be surrounded and destroyed

You should also be aware that getting caught in a hex between two enemy units (or between enemy and impassable terrain) reduces your next move 'range' to a single hex !

Whilst the 'single hex trap' does not apply to air units, it makes outflanking an opponent almost impossible tiny mixed terrain maps. Instead of 'punching a (single unit wide) hole' in the enemy line you have to punch a 3 unit wide hole - and since your Tanks only move about 5 hex's (except on roads) 'flooding through the gap' is more like a 'trickle' :-)

Be aware that when in a 'transport' type unit, damage to transport is also applied the units inside.

It's generally not worth the risk trying to use Transport units to 'evacuate' the 'wounded' (Transport aircraft in particular are very vulnerable and taking one or two damage points to the aircraft means anything inside on 1 or 2 strength will be lost)

The 'Scout' unit type may be fast moving, but it's rather easy to kill. It does, however, have a 'range attack' capability (unlike APC's & Tanks etc).

Scouts are best used for indirect fire 'support' unit (i.e. positioned directly behind an attacking unit) as self-propelled mortar / howitzer, and for sure not wasted by rushing off in front of your forces (where they will just be 'premium' target)

Repairing costs the same resources ('5 crystals') and takes the same time (1 turn) no matter what the damage or original 'cost' of the unit and reduces the units 'combat experience' level. Plus you have to 'return to base'.

When you take into account the very low resource generation rate on just about every map (and the position of your base / factory / depots, typically multiple turns to your rear), it's only ever worth repairing the most expensive (and fastest) unit types i.e. your aircraft.
Other damaged units are better used to tempt the enemy out of position, used to 'support' your attacks (by lending a flanking/rear 'bonus') or as 'cannon fodder'

Submarines can only 'move' in deep water and have no 'dive' capability (so can't 'hide' from the enemy).

The real advantage of Submarines is their 3 hex range attack capability. This allows you to use them as 'Sea Artillery' from the 3rd rank (i.e. behind the Torpedo Boats in the second rank which are themselves fighting behind the Patrol Boats in the first rank).
NB. Note that Submarines (& Torpedo Boats) can even fire at any non-Air enemy unit on a 'sea' hex - which means you can 'torpedo' Hovercraft - even if that unit is 'behind' an intervening friend, enemy or even a land hex :-) (useful, when you discover that sea units can't pass under road or rail bridges - although Patrol and Torpedo Boats can navigate Rivers !)

Transport ships are limited to deep or medium water (so no beach landings and no sneaking up rivers :-) )

Hovercraft (which are absurdly 'powerful' and can carry Heavy Tanks !) are limited to shallow or medium water

The "Mine" unit is a sort of 'concrete tank trap' (or, at Sea, a 'floating rock') since all they can be used for is to 'block' the movement of other units. They are quite tough, but can be 'destroyed' with impunity since they don't even 'fight back'

Land mines are only ever 'pre-deployed' (no land unit can carry mines, although it's easy enough to change that)
Sea mines can be carried and deployed by Patrol Boats, plus Patrol Boats can also 'Sweep' mines (i.e. pick them up and use them again :-) )
Note that you can't 'attack' your own mines (so, unless 'swept', they become an impenetrable barrier to your own forces !)
You can, however, fire under a Mine. So position your Torpedo Boats & Submarines behind a line of mines and fire at the enemy forces that the AI will always move up to attack your Mines (even if these could be bypassed eg by taking a slightly longer route), since the AI is always focused on 'killing the enemy' (even when the 'enemy' consists of harmless 'floating rocks' :-) ).
The way mines are used is such total nonsense that it was one of the very first things I 'fixed' (changing the existing 'mine' unit icon into a 'concrete block' was a good first step :-) )

Watch out for some unrealistic terrain effects on movement.

The 'Barbed wire' (a thin white line across grass) tile prevents the movement of everything (except aircraft), including Tanks !
The Tank Trap (4 or 5 'diamonds' on grass) tile allows Infantry to cross (OK), but also also 'Anti-Aircraft tanks' :-)
Note that since both Barbed wire and Tank Traps are types of terrain, they can't be 'attacked' or destroyed.
Tarmac roads (but not the 'sandy' coloured tracks) effect movement (in fact, Roads allows Heavy Tanks to move faster than Helicopter Gunships (7 hex's v's 6) !!!!)
Transport Ships are limited to deep and medium sea terrain - so no beach landings - and Subs to deep water (only) so (usually) no way to 'return to base' or even get close enough to attach enemy 'Boats'
All sea units are 'blocked' by bridges (which is annoying, but easy to fix)
There is a 'small bridge over river' tile (not part of a Road or Track) that only allows Infantry to pass.

Resources ('crystals')

On most maps the buildings have no 'resource generation' capability, so, after the (usually very) limited 'stock' of resources have been 'used up' you can't build or repair anything

Buildings  with no resources are of no real use - except your HQ, loss of which will usually means you are instantly defeated - so is not even 'worth' defending UNLESS they are mentioned in the 'Objectives'.
Note that transport units (including APC's) can be loaded with resources ('crystals') at one building (such as a 'Depot') where 'crystals' can be found stored on some maps and then moved to a Factory (where they are rather more useful :-) )
This also means you can move resources from a building far to your rear to one 'at the front' (or even to a captured building) in order to make use of the 'repair' facility

Crimson Fields software (source code) modification

Whilst Crimson Fields can be found in the Source Forge directory it is not (yet) an actual project

Building CF from it's source code is not easy. To see how I managed it (eventually), go to my  Building CF for Windows page

Once you have the ability to build from the source code it is easy to make changes to the Unit data (for example, give Mines an 'attack' value), add extra units or even add extra Terrain tiles, all without having to modify any actual C++ code !

As you will see later, I was even able to double the size of the map 'tiles' without needing to work out exactly how the map display functions actually worked

The pages in this topic are :-

  + Better battles

  + Annoyances and issues == Latest changes (modified 2nd Jan 2018 17:10.)

Next page :- Better battles