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Author Topic: UFO_170.map and the universal patch  (Read 4059 times)

Offline Player701

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UFO_170.map and the universal patch
« on: August 05, 2018, 10:50:07 am »
Hi.

I've been playing XCOM 1 using OXCE+ and sometimes there have been cases where aliens on the second floor of the Supply Ship UFO can see my soldiers down below and shoot through the wall / floor. I thought it was an engine bug at first but then I found this and eventually it led me to this thread where people say the issue is fixed in the universal data patch provided here: https://openxcom.org/download/extras/universal-patch.zip. However, I have the patch installed and the issue is still present.

To quote the aforementioned thread, user hellrazor posted an attachment with the fixed UFO_170.map file and user Tarvis said:
Well, I don't know what to tell you. hellrazor's modified map file is identical to the one in the universal patch.
I just checked and this is not true. Even the size of the two files differs (attached is 9604 bytes long, the one which comes with the patch is 9603 bytes long). hellrazor's attached file does indeed seem to patch the "hole" in the UFO. If possible, could the maintainers of the patch update it with the fixed file? Thank you very much.


Offline Warboy1982

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Re: UFO_170.map and the universal patch
« Reply #1 on: August 07, 2018, 11:58:28 am »
wait, what? i'm like 99.99% sure i've dealt with this in the past... at least twice
of course, this is xcom, so even 100% isn't an absolute.

can anyone else confirm?
all the versions i have are correctly fixed as far as i can tell.

Offline Player701

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Re: UFO_170.map and the universal patch
« Reply #2 on: August 10, 2018, 09:27:05 pm »
Well, since no one has bothered to check, here is a detailed comparison of the two files.

You can see the difference on the first screenshot. The version from the Extras patch has byte 00 occupy the offset 1A0B, while hellrazor's version has byte 19 at this offset. This byte corresponds to the "ground" value of the 17th tile in the 16th row on the 2nd level of the map. With the MapView tool it can be seen that the ground is indeed missing in this particular tile in the Extras version of the map - which is exactly the point from where I can spot targets below and shoot at them (of course, the aliens have this advantage most of the time, but I've run a few tests in debug mode as well).

There is also an extra byte at the end of the file in hellrazor's version, making it 9604 bytes long, which is one byte longer than the intended value of 9603 (because 3 bytes in the beginning specify the dimensions of the map and the remaining part is composed of 4-byte records). I guess this extra byte is simply ignored by OpenXcom, so it doesn't really make much difference - although it makes it possible to simply compare how long the files are to refute the claim that hellrazor's version is the one which comes with the universal patch (because it is not).

Perhaps there is a new version of the patch somewhere which is not that easy to find? Similar to how "1.0" is posted as the latest release on the main page and the nightlies are a bit harder to discover for the uninitiated.

Offline The Reaver of Darkness

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Re: UFO_170.map and the universal patch
« Reply #3 on: August 14, 2018, 10:54:19 pm »
I am not experiencing the issue. I can confirm that the map file I am using for the supply ship does have the hole (seen in MapView), but does not have the hole present in-game (unable to fly up).

Versions tested:
OXC Nightly 2017/11/09
OXCE+ 3.10b 2018/07/21

Offline Player701

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Re: UFO_170.map and the universal patch
« Reply #4 on: August 14, 2018, 11:15:08 pm »
I am not experiencing the issue. I can confirm that the map file I am using for the supply ship does have the hole (seen in MapView), but does not have the hole present in-game (unable to fly up).

Versions tested:
OXC Nightly 2017/11/09
OXCE+ 3.10b 2018/07/21

It is indeed not possible to glitch through the UFO hull using this hole; perhaps OpenXcom fixes the behavior so that flying up into objects is not possible. However, shooting through the hole is still possible. Try aiming at the tile below the one highlighted on the attached screenshot, while standing at the same place where the soldier is. Most of the time the shot will hit the UFO floor (guess this is due to rookie's low firing accuracy), but sometimes it will pass through to the ground. There certainly is a valid line of fire there, which can and will be used by aliens provided they are in the right position. I have experienced this several times during supply ship assaults.
« Last Edit: August 14, 2018, 11:22:21 pm by Player701 »

Offline The Reaver of Darkness

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Re: UFO_170.map and the universal patch
« Reply #5 on: August 15, 2018, 12:44:04 am »
Confirmed. Can see through and shoot through. Merely cannot move through.