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how to play perditions gate?

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i got Perdition's Gate, so my question is, how to run it?

is it only possible with dos doom 2? or is there a way with doom95. i found some patches for zdoom here but i dont get how to load it.


ok it started under dos...whats the difference between all the wads? PGDEMO16.WAD PGDEMO17.WAD PGDEMO18.WAD PGDEMO19.WAD PG-RAW.WAD PG-RAW-X.WAD PerdGate.wad. why so many wads? its so confusing.

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Basically, to play, you need the PG-RAW.WAD (or PG-RAW-X.WAD; they are mostly identical).

Then you need a modern source port. Like ZDoom, Eternity, or PrBoom+.

Load PG-RAW.WAD directly in the modern port of your choice (see informations here for ZDoom; other ports work similarly).

Now, for some background technical information:

The original, vanilla Doom engine did not allow to add custom sprites to a PWAD in an easy and straightforward manner. WAD files are sequential archives, and individual lumps can be retrieved by their name or by their number (the first lump is 0, then the next is 1, and then 2, and so on). Quite often, the game refers to things by numbers, for example when loading a map it'll get the number for the map header (e.g., MAP01), then load things from header+1, linedefs from header+2, and so on.

When it looks for lumps by their names, it has to search all lumps for this name. It starts at the very last, compare the name, if it doesn't fit it looks at the lump before, compare the name, and so on.

To make things a bit faster, it has namespaces. So it keeps in memory the index number for namespace delimiters (the *_START/*_END marker lumps), and if it looks for a sprite, it'll start from S_END - 1 and look back until it reaches S_START. Likewise, if it looks for a flat, it'll start from F_END - 1 and look back until it reaches F_START.

Now here comes an interesting thing: when you load PWADs, they are added to the sequence. That is to say, the first lump in your PWAD will come right after the last lump in the IWAD. (And if you load several PWADs, they are similarly queued together.)

So for example, if you add a new MAP01 in a PWAD, it'll replace the MAP01 from the IWAD (since it searches starting from the last). That's how it works.

But of course, you can only have one of each namespace. Suppose it looks for a flat that only exists in the IWAD, and you have both F_START and F_END in your PWAD: it will not find it. Likewise when looking for an IWAD sprite and S_START and S_END are in your PWAD.

There is a trick, though: suppose you only have F_END in your PWAD; but no F_START at all: when looking back for it, it'll reach the F_START from the IWAD; so all the flats in your PWAD and all those from the IWAD will be looked at. As well as many non-flat lumps; but that's usually not a problem as long as they don't have the same name.

However, you cannot do that for sprites. When loading, the game tries to make sure that all sprites obey the proper sprite naming convention. And fatally, there are lumps not named in an acceptable way after the IWAD sprites (starting with S_END...).

So, because of this, all sprites used in the game must be in the same, continuous namespace. Either all in the IWAD, or all in the PWAD. Suppose you only want to replace a few of them, but not all of them: you're screwed. You either also include a copy of all the unmodified IWAD sprites (and make your mod a lot larger, and arguably illegal), or you inject the modified sprites in the IWAD directly, which you must then distribute (and that is definitely illegal).

So, to solve the problem, people created some utilities such as DeuSF or NWT. You'd use them to merge in your PWAD all unmodified IWAD sprites (or merge the modified sprites from the PWAD in the IWAD), but that'd only happen on the user's computer. This way, you didn't need to distribute unmodified resources.

That's what Perdition's Gate, and many other partial conversions of the era, did; and that's why there's such a complicated installation procedure.

However, with modern source ports, all that stuff is no longer relevant. They are perfectly able to have the same namespace in duplicate, triplicate, etc. In short, you no longer need to bother with DeuSF and NWT at all.

PG-RAW.WAD contains the raw modified or original data from Perdition's Gate. Normally, the installer merges in IWAD data to create a file named PERDGATE.WAD. But you don't need that anymore. You can load PG-RAW.WAD directly and it'll work.

(But if you really want to use Doom95, follow the install procedure and load PERDGATE.WAD once it's generated.)

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hey thanks. good explanation why these old addons are so complicated.

i was a bit confused with the shortcut path, because i did a custom directory called "wad". it must be E:\GZDoom\gzdoom.exe wad/perdgate.wad . now i get it. these path things are not for me. i also forgot there is this great drag and drop function.

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If you are using Windows or Linux, you just need to drag the perdgate.wad and drop over the gzdoom.exe
You only need to use other complicated ways if you are using a Mac system.

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Badboy said:

whats the difference between all the wads? PGDEMO16.WAD PGDEMO17.WAD PGDEMO18.WAD PGDEMO19.WAD . . . why so many wads? its so confusing.

They're demo packs for the different version releases of Doom 2, all you need is the one that matches your DOS engine version. I don't think maintaining backward compatibility for demo playback was high on John Carmack's to-do list, as a result, a demo recorded on one engine version tends to desync when played back on another.

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On 3/30/2021 at 2:54 AM, VentoliN13 said:

What's the difference in Pardition's Gate and Pardition's Gate X versions? Someone please explain this to me. . .

The difference is minimal, as far as I know it's only relevant if you're looking to play Perdition's Gate on the original executable/Chocolate Doom. So pick your poison :)

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