Chaos Engine level viewer

[Kroah]

Hi all,

I'm actually finishing a chaos engine viewer i begun some years ago (based on the CD32 version). Maybe you know my website about game decompilation (mainly on Atari): http://bringerp.free.fr/RE/

I've reverse engineered some parts of the chaos engine binary to better understand the engine, sprites/palette creation and files structures. I never saw a game with so many strange things about files... probably a consequence of the CD32 conversion.

The utility allows you to view (of course) and execute some actions like activating triggers, getting items, running scripts and killing monsters while the map reflects the changes. All data are extracted on the fly from original ones (with or without RNC compression). By the way, i discovered what i call "RNC archive" which is several RNC files stored in one file...

Even if i code all my tools to fulfill my curiosity, i hope you'll be interested in it.

To complete it, i'll need some feedbacks concerning the puzzles:

- Do you remember if you came across some puzzles you've never been able to solve and/or were never explained by walkthroughs?

- Do you remember some puzzles behaving incorrectly?

Edit: I just saw the amiga longplay "Amiga Longplay [169] The Chaos Engine" on YouTube ( [ Show youtube player ]). I'm a little surprise the player resolves so few secrets. Maybe he does this with a speedrun in mind?

Edit2: The replay "Amiga Longplay [328] The Chaos Engine (a)" [ Show youtube player ] is a lot better.

Thank you,
Kroah

[Exl]

That is amazing! I would love to take a look at the code, or how in the hell all the data is laid out in the files. The questions and riddles have not left my mind, they want to be answered!

[Qube]

Kroah - looks very good indeed! Regards puzzles n the like, I recall in one of the walkthroughs of the Rings level (W1L3) that there was a key which could not be collected or something, I'll have to re-check that though. The other thing which was always weird was how on the very last level, if you open the map view, you will see a strange exit shown to the very bottom or something like that..

Was a superb game though. Needs a remix perhaps one day, 4 player internet, but using the same 2D gfx n the like perhaps, maybe a CE3 : Return To Chaos or somin, years later going back to see what happened to the ruins etc... To think they could have done some neat things with Chaos, like introduce a female character even, daughter of the Navvie or somin eh lol.

Q;

[jotd]

Kroah please make your viewer available, and with source code if possible!

The CD32 version is strange because there are mixed ECS pictures and "AGA" (actually 4 bit per pixel) graphics for characters and some monsters.
But that's not new: Cadaver (PC) has 3 types of 16 color graphics: what I call EGA for the most of gfx, amiga bitplanes for the main character (with a 5th bitplane for mask), and ST bitplanes for fonts and dashboard !

I think it depended on the tools the designers used for each sprite/animation.

[Kroah]

Hello jotd,

Originally Posted by jotd

Kroah please make your viewer available, and with source code if possible!

Yes, i'm finishing some stuffs and i'll release it. I always provide source code on demand, so be it.

Originally Posted by jotd

The CD32 version is strange because there are mixed ECS pictures and "AGA" (actually 4 bit per pixel) graphics for characters and some monsters.
But that's not new: Cadaver (PC) has 3 types of 16 color graphics: what I call EGA for the most of gfx, amiga bitplanes for the main character (with a 5th bitplane for mask), and ST bitplanes for fonts and dashboard !

You are right.

There are at least 5 encodings for sprites (all are 4 bitplanes (16 colors) but the last one):
- 1 chunky (like on PC)
- 3 planars (ST format) with different interleaves (1 byte for 8 pixels width, 1 word for 16 pixels width and 1 dword for 32 pixels width). I say ST format because the AM planar format is not interleaved (or sometimes by scanline).
- 1 planar AM (variable bp)

That's why the sprites are 16 colors among the 256 colors palette (There is 1 palette for each world and a special one for the last level).

But what i really don't understand is the directory:
- All .SIN files are the exact copy of their corresponding .BIN file. They are useless.

- The STATIC.BIN file contains 7 files (getready.bin, expl1616.bin, nodes.bin, expl3232.bin, tranmask.bin, panel.bin and sp8x8.bin). Those 7 files are in the directory too but never used (the ones in static.bin overwrites them). Among those 7 files, only getready.bin and expl1616.bin are different.

- SNGARC.BIN is a RNC archive containing 29 RNC files:
000-003 world RJP sng (1 for each world)
004 title RJP sng
005 end level table gfx
006 all hire gfx (AM)
007-022 the level entities datas (monsters, nodes) (1 for each level)
023-026 world items gfx (1 for each world)
027 hire table gfx
028 "the chaos engine cd32 version" gfx

- SNGARC2.BIN is a RNC archive containing 11 RNC files:
000-008 the renegade gfx (all the same but pointing to the same data in the RNC archive)
009 "a bitmap brothers game" gfx
010 "the chaos engine cd32 version" (same as 028 from sgnarc.bin)

I know porting a game may need to change some files format, renaming them, etc... But here there are really strange things. Seems they have left they WIP files in the directory?

[jotd]

thanks for the info!! Exl was looking for node & enemy info everywhere. I would not have thought that it was in SNGARC.BIN!
The rest I pretty had it figured out. I started a RJP player, pretty much figured out the data format too (using Cannon Fodder song) but did not complete it. I can decode most of the data (using the asm source this time), but the format is awful.

BTW I've got a trick when I create dump programs: I dump the hex data but I replace the data by _ chrs where I know what it means:

05 67 __ __ 43 23 __ 01 00 __
and print them decoded below.

So when I get all __ I know all is decoded. Worked well for cadaver, even if there are still undecoded parts (I don't resource the code, so it's a little trickier )

about leaving the files in the directory, what do they care, as there is a lot of space on the CD. This info is very valuable for the WHDLoad slave, though: the data could be left off the HD so PRELOAD eats less memory.

[Kroah]

Originally Posted by jotd

thanks for the info!! Exl was looking for node & enemy info everywhere. I would not have thought that it was in SNGARC.BIN!

Yes i was puzzled about that too. What a strange design choice.

Originally Posted by jotd

BTW I've got a trick when I create dump programs: I dump the hex data but I replace the data by _ chrs where I know what it means:

05 67 __ __ 43 23 __ 01 00 __
and print them decoded below.

So when I get all __ I know all is decoded. Worked well for cadaver, even if there are still undecoded parts (I don't resource the code, so it's a little trickier )

I used to work in a similar way (and still sometimes do). But since i discovered 010 Editor some years ago, i rely heavily on it.

Concerning .ANI files, they -seems- to be regular IFF animation (standard header and chunks).

I've tried several IFF ANI players on PC and Amiga (DP V, Personal Painter), but none of them handle the IFF. Whether i'm wrong and they'are not so regular that i thought, or i've made a mistake.

Any ideas?

[Exl]

Originally Posted by Kroah

I've tried several IFF ANI players on PC and Amiga (DP V, Personal Painter), but none of them handle the IFF. Whether i'm wrong and they'are not so regular that i thought, or i've made a mistake.

Any ideas?

The IFF Anim players I fed them to (those that I could find right now) did not want to play them. Maybe they use some custom adaptations...?

Any progress on other parts of it?

[Kroah]

Hi all,

Originally Posted by Exl

Any progress on other parts of it?

I need some testing.

Anyone here has some spare time and knows sufficiently the game to give usefull feedbacks? I'll send the program via PM.

Thanks

[Exl]

I have spare time, though I don't know the game by heart if that is what you mean.

[Kroah]

Originally Posted by Exl

I have spare time, though I don't know the game by heart if that is what you mean.

Thank you, i've sent you a PM.

Anyone else interested?

[lilalurl]

Originally Posted by Kroah

Anyone else interested?

If you need that on short-term, sorry.
Otherwise, next week I should have some free time. Finished CE a few times but don't know it by heart.

[Kroah]

Originally Posted by lilalurl

If you need that on short-term, sorry.
Otherwise, next week I should have some free time. Finished CE a few times but don't know it by heart.

You're right, i hope putting the viewer online this week if i have enough feedbacks to fix potential bugs.

But your feedback is welcomed after that anyway .

[Exl]

I've had a quick look at it so far, and it is a very impressive piece of work! Regarding entities, I figured out some more of the fields a while ago;

short    X
short    Y
byte    Health
byte    Speed

byte    Unknown3
byte    Unknown4

byte    linkDeath
byte    Angle?

byte    Unknown7

byte    Class
byte    Attack
byte    attackDelay
byte    attackSpeed
byte    attackDuration

byte    Unknown13

byte    Link

short    Unknown15

This is by modifying the values in memory while the game is running (but before you start playing), and seeing what effect they have. Tedious work...

Anyway, I'm not 100% sure about the Angle (1-8 clockwise, 0 for facing player maybe). The Attack seems to describe what type of attack the entity has (see http://www.dvdflick.net/storage/ce_attacks.txt ), with the attack delay, speed (of the projectile) and duration (lifespan of projectile i.e. max. distance it travels) serving as parameters. The linkDeath field describes a link that when activated, kills\removes the entity from the level. "Unknown15" seems to be 0 in all levels.

As far as a cover's 28b_unkEffect field, here's what I found out;

Effects
=========
Values repeat in effect every multiple of 32. Despite being a flag, the
crossfade effect doesn't seem to combine with any of the pop effects. All other
values cause no effect to be used. I'm probably reading them wrong from the
file...

1   Top left pop
2   Top center pop
3   Top right pop
4   Center left pop
5   Center pop
6   Center right pop
7   Bottom left pop
8   Bottom center pop
9   Bottom right pop

17  Top left large pop
18  Top center large pop
19  Top right large pop
20  Center left large pop
21  Center large pop
22  Center right large pop
23  Bottom left large pop
24  Bottom center large pop
25  Bottom right large pop

255 Crossfade

A "pop" being one of those small white explosion things you also get when a coin vanishes. I realize the values are probably flags or something, and I'm interpreting the value wrong, but it's something at least.

I'll continue to peer through the viewer, and see if I can find some more things to comment on.

[Kroah]

Originally Posted by Exl

I've had a quick look at it so far, and it is a very impressive piece of work!

Thank you.

Originally Posted by Exl

Regarding entities, I figured out some more of the fields a while ago

I take note of these useful information!

Originally Posted by Boo Boo

Thanks Kroah i'm very intrested in this kind of thing, I just wanted to ask - do you intend to turn the viewer into an editor?

Well, i will love writing an editor for Chaos Engine, but there are many things hardcoded in the binary and many unknown fields in the data. I'll have to spend more time than i have to find out them.

But the main sensible point imho is the way level data are stored. Some are in the famous ".CAS" files, some in the RNC archive (like the nodes and monster classes of the level). Updating them is a lot of work (rebuilding the RNC archive...). And some files have their length hardcoded in the binary.

Maybe the floppy disk version (ST) has an easier way to store/retrieve data (even if the disk has no file system and data are raw stored). For example Time Bandit does not have any file system on ST, but once mapped, it's easy to expand the levels in size.

[Kroah]

I've updated my reverse engineering page.

You'll find a new section about Chaos Engine. Not much for now besides my Chaos Engine Viewer.

You can download it there:
Kroah's Game Reverse Engineering Page

I'll add a little doc soon. Until then, try left click (simulate hero moves and script steps) and right click (simulate hero missiles) on colored squares.

Any comments are welcomed .

Have fun!

[Crashdisk]

Thanks ^^

[Qube]

Kroah - wicked viewer, very professional look to it also. You sure have worked out a lot of stuff eh. Chaos really is one of the best games made, always a fun blast! Reverse engineering can be such a blast also.

Q;

[jotd]

Just checked the viewer. Excellent stuff. Now you HAVE to code a remake or an editor, whatever the difficulty is
I'm taking care of Magic Pockets & Cadaver.

[Kroah]

Could anyone post in the zone a filed version of Chaos Engine ECS/OCS?

Edit: i have tried to extract the files from some versions i have ([cr FLT]), but even if there's "DOS" in the header with the filenames readable, i can't extract anything. I haven't tried the SPS version.

Thanks in advance!