Terminal Velocity: Christmas on Ymir

The Rectifier · 06-14-2011, 06:51 PM

I turned the pine trees into Christmas trees!

And no, it's not a doctored image...I made a new tile.

Malvineous · 06-15-2011, 06:37 AM

That's a coincidence, today I started examining the TV file formats in more detail as well. Any idea how the levels are constructed? I'm not sure if it's one of those 256x256 images or whether it's made up from the 400-odd coordinates listed in the .def files.

Also in one of the Ymir map files I found the string "Help the Tree People of this Planet! :)" but I've never seen that in-game before. It was in with the descriptions of the enemy aircraft that you see at the start of each planet.

The Rectifier · 06-15-2011, 02:54 PM

This site may have some answers for you.

Have you experimented with TVCad? It's the level editor for TV. It's pretty basic, but you can change the height of the terrain and the attributes of the objects (aircraft, ground targets, static objects, etc.)

The text you found is for the tactical report at the beginning of the level. Not all objects are "visible" in the report by deafult - you can use TVCad to change that.

I've also been using Game File Explorer for taking files out of .PODs, FlyRawGui for converting between .RAW and .BMP for editing tiles, and PODtool for making new .PODs.

Aside from the Christmas tree tile, I've made a .POD that changes Ymir back into a snow planet using tiles from TV 1.1. I always liked it better that way.

Malvineous · 06-15-2011, 04:36 PM

Oh wow, I had no idea anyone had already reverse engineered all the TV file formats! No I haven't heard of TVCad, but that's good to know there are already editors around for it - less importance to implement TV stuff in Camoto, as I'm trying to focus on games that don't already have editors first!

Thanks for the links though, very interesting...

The Rectifier · 06-15-2011, 05:10 PM

TVCad is available on the 3D Realms download page (although you have to register with File Planet to get it.)

Although not an Apogee game, Ancient Empires by The Learning Company does not have a level editor. I would love to see one if you're taking requests.

Malvineous · 06-16-2011, 03:02 AM

Ha, another coincidence - right before I was looking at Terminal Velocity I was poking around in Treasure Mountain and Midnight Rescue, two other games by The Learning Company. If you're keen on getting an editor for any game, the best chance is to make sure all the game's file formats are well documented, like on that wiki you posted (or the ModdingWiki which is a similar one that I run.) Reverse engineering file formats takes time, so all the games with known file formats are likely to be implemented first!

The Rectifier · 06-16-2011, 02:41 PM

I remember making an attempt at "editing" Treasure Mountain when I was about 8... It did bad things to the game.

Very little comprises Ancient Empires. Just a 78 kilobyte executable and two .dat files. One of the .dat files stores not only game data but user data as well, because the timestamp changes everytime one plays the game.

I can screw around with TV tiles all day, but when it comes to poking around in code I am totally lost. I tried using WinHex to change the number of force shields a player gets in AE, which is hard coded at 4 to something like 999, but I had no idea where to even start.

Malvineous · 06-17-2011, 07:57 AM

Changing the behaviour of games (force shields, enemy AI, powerups, etc.) is much more complex as you need to turn the machine code back into something human readable, and then know enough about writing computer programs in assembly language to understand how to read it.

But changing game data (images, maps, sounds, etc.) is far easier because these types of files are usually stored separately (e.g. in .dat files) and often in one of a relatively small number of known formats. So it can be pretty easy to figure them out.

Take a look at duke3d.grp in your hex editor for example. You can immediately see a bunch of filenames, with each filename followed by four bytes of data. Those four bytes are the lengths of each file, so by adding all the lengths up you can figure out where a given file's data starts. (The first file starts after the list of filenames, the second file immediately following the first, and so on.) Even without that as you look through the .grp file you will see text like "Creative Voice File" (the start of a .voc sound) or "MThd" followed shortly by "MTrk" (the start of a .mid music file.) These are the sorts of things I am documenting on the ModdingWiki, and indeed the GRP format is already detailed on there. Once you start poking around in files like these you get pretty good at recognising what particular file formats look like - for this reason a hex editor which can display 8-bit ASCII is a must. I recommend Vernon D. Buerg's DOS-based program "List". The hex view (Alt+H) is ideal.

Going back to the topic (sort of) your TV modification gave me an idea. I thought it would be interesting to modify the fog map so that instead of fading everything out to white, it could fade everything out to blue, as if you were underwater. Submersible TV would be an interesting mod! Unfortunately changing the fog map didn't quite work as well as I'd hoped!

06-14-2011, 06:51 PM	#1
The Rectifier	Terminal Velocity: Christmas on Ymir I turned the pine trees into Christmas trees! And no, it's not a doctored image...I made a new tile.

06-15-2011, 06:37 AM	#2
Malvineous	Re: Terminal Velocity: Christmas on Ymir That's a coincidence, today I started examining the TV file formats in more detail as well. Any idea how the levels are constructed? I'm not sure if it's one of those 256x256 images or whether it's made up from the 400-odd coordinates listed in the .def files. Also in one of the Ymir map files I found the string "Help the Tree People of this Planet! :)" but I've never seen that in-game before. It was in with the descriptions of the enemy aircraft that you see at the start of each planet.

06-15-2011, 02:54 PM	#3
The Rectifier	Re: Terminal Velocity: Christmas on Ymir This site may have some answers for you. Have you experimented with TVCad? It's the level editor for TV. It's pretty basic, but you can change the height of the terrain and the attributes of the objects (aircraft, ground targets, static objects, etc.) The text you found is for the tactical report at the beginning of the level. Not all objects are "visible" in the report by deafult - you can use TVCad to change that. I've also been using Game File Explorer for taking files out of .PODs, FlyRawGui for converting between .RAW and .BMP for editing tiles, and PODtool for making new .PODs. Aside from the Christmas tree tile, I've made a .POD that changes Ymir back into a snow planet using tiles from TV 1.1. I always liked it better that way.

06-15-2011, 04:36 PM	#4
Malvineous	Re: Terminal Velocity: Christmas on Ymir Oh wow, I had no idea anyone had already reverse engineered all the TV file formats! No I haven't heard of TVCad, but that's good to know there are already editors around for it - less importance to implement TV stuff in Camoto, as I'm trying to focus on games that don't already have editors first! Thanks for the links though, very interesting...

06-15-2011, 05:10 PM	#5
The Rectifier	Re: Terminal Velocity: Christmas on Ymir TVCad is available on the 3D Realms download page (although you have to register with File Planet to get it.) Although not an Apogee game, Ancient Empires by The Learning Company does not have a level editor. I would love to see one if you're taking requests.

06-16-2011, 03:02 AM	#6
Malvineous	Re: Terminal Velocity: Christmas on Ymir Ha, another coincidence - right before I was looking at Terminal Velocity I was poking around in Treasure Mountain and Midnight Rescue, two other games by The Learning Company. If you're keen on getting an editor for any game, the best chance is to make sure all the game's file formats are well documented, like on that wiki you posted (or the ModdingWiki which is a similar one that I run.) Reverse engineering file formats takes time, so all the games with known file formats are likely to be implemented first!

06-16-2011, 02:41 PM	#7
The Rectifier	Re: Terminal Velocity: Christmas on Ymir I remember making an attempt at "editing" Treasure Mountain when I was about 8... It did bad things to the game. Very little comprises Ancient Empires. Just a 78 kilobyte executable and two .dat files. One of the .dat files stores not only game data but user data as well, because the timestamp changes everytime one plays the game. I can screw around with TV tiles all day, but when it comes to poking around in code I am totally lost. I tried using WinHex to change the number of force shields a player gets in AE, which is hard coded at 4 to something like 999, but I had no idea where to even start.

06-17-2011, 07:57 AM	#8
Malvineous	Re: Terminal Velocity: Christmas on Ymir Changing the behaviour of games (force shields, enemy AI, powerups, etc.) is much more complex as you need to turn the machine code back into something human readable, and then know enough about writing computer programs in assembly language to understand how to read it. But changing game data (images, maps, sounds, etc.) is far easier because these types of files are usually stored separately (e.g. in .dat files) and often in one of a relatively small number of known formats. So it can be pretty easy to figure them out. Take a look at duke3d.grp in your hex editor for example. You can immediately see a bunch of filenames, with each filename followed by four bytes of data. Those four bytes are the lengths of each file, so by adding all the lengths up you can figure out where a given file's data starts. (The first file starts after the list of filenames, the second file immediately following the first, and so on.) Even without that as you look through the .grp file you will see text like "Creative Voice File" (the start of a .voc sound) or "MThd" followed shortly by "MTrk" (the start of a .mid music file.) These are the sorts of things I am documenting on the ModdingWiki, and indeed the GRP format is already detailed on there. Once you start poking around in files like these you get pretty good at recognising what particular file formats look like - for this reason a hex editor which can display 8-bit ASCII is a must. I recommend Vernon D. Buerg's DOS-based program "List". The hex view (Alt+H) is ideal. Going back to the topic (sort of) your TV modification gave me an idea. I thought it would be interesting to modify the fog map so that instead of fading everything out to white, it could fade everything out to blue, as if you were underwater. Submersible TV would be an interesting mod! Unfortunately changing the fog map didn't quite work as well as I'd hoped!