Author Topic: SGP: The Modified Gothi Hypothesis or "Bump Glitching"  (Read 3643 times)

ColdGlider

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SGP: The Modified Gothi Hypothesis or "Bump Glitching"
« on: October 09, 2009, 05:01:15 »
Many people (including myself) have already gotten the "Glyph Unlock" to work without getting face-to-face with a glyph in District 06.  So my video, posted on October 4th, needs to be updated.   This is essentially old news.

So I hereby bury the term "Glyph Unlock".  It has been Gothied.

Why did it take so long for me to admit "defeat"?  Well, for one I have been spending ridiculous amounts of time administering the SGP in lieu of actually playing ODST!  Additionally, I wanted to present a replacement hypothesis that would stand up to rigorous testing and hopefully become a theory.  I believe I have found that replacement.

In a sense, this hypothesis is proof of both Gothi's "loading glitch" assumption and my... errr... previous theory (as seen distributed via YouTube).  In reality it is based completely on technical aspects of the game engine's data loading processes as merely deduced though testing and observation.  It is not based on fictional Halo concepts.  The mystery of the glyphs continues.  Due to its technical nature, not everyone will be able to follow along with the details I provide in the "Assumptions" and "Hypothesis" sections.  Hopefully most will be able to follow the "Proof" and will therefore be able to get to the good stuff, as it were.  

I have tested this.  It does work.  (Just like last time!)  The glyphs are not technically in the equation but they do coincidentally mark the key position required to obtain the results shown in my video.  Can this hypothesis be applied to other Districts?  Not only some, but all; however, it remains to be seen how the other districts are affected.  

Of course I had to try it somewhere else and get some new results!  I can report that the "Bump Glitch" removes two locked security doors (the tall dark ones) which lead into the southwest courtyard in District 03.  The bad news is: behind each door is an utterly jet black wall!  Not the kind of breakthrough discovery I wanted to report, but if I spend time looking for the goodies you won't get a chance to find them first!  

So let's learn about "Bump Glitching"...

Most of the abbreviations and terms I end up using in this description are explained as I go.  One notable exception is BSP.  For those who don't know, "BSP" is technical talk for "Halo level data".  That's enough to get you through this!

Disclaimer:  I have never built (or taken apart) a Halo level in my life, although I have designed first-person shooter levels in the past.  I do not know what Bungie's internal names are for the components of their architecture blah, blah, blah.  Do all of the processes I describe exist exactly as I describe?  No, that would be impossible for me to do unless I worked a dream job at Bungie.  The point here is that they don't have to be exact... they accurately describe the game's behavior in a way that allows you to reliably repeat the removal of some objects in the game levels.

Assumptions
  • Each time the "Loading... done" message appears, BSP data has been loaded for the District you are about to enter.  This loading occurred because you triggered a "BSP Loading Point"
  • The game engine keeps two BSPs loaded at a time into two separate BSP Memory Areas (BMAs).  I call these the "Current BMA" (or "cBMA") and the "Adjacent BMA" (or "aBMA").  When you request a third district to load, the BSP data for that third district is loaded into the Adjacent BMA, replacing whatever BSP was loaded in there previously.  When you enter the new district, you effectively swap the BMA assignments as the Adjacent BMA becomes the Current BMA and vice versa.
  • When you trigger a BSP loading point, the game engine checks to see if the requested BSP is already loaded into the the Adjacent BMA in case reloading is not required.  I call this a BMA check.  If this check passes, no loading is done.

Hypothesis

BMA Checks
BMA checks are comprised of two separate checks: a BSP ID Check and a BSP Integrity Check, which occur in that order.  

The ID Check looks to see of the ID of the BSP (which district it belongs to) is the same as the one it is requesting to load.  In other words, if the BSP data is already in there because you're going back to the district you just came from.  If this check fails (because you are entering a new district instead of backtracking) then it skips the Integrity check and loads in the requested BSP.

The integrity check is only called if the ID Check passes; thus, every time the integrity check is called the BSP ID requested (e.g. the ID for District 06's BSP data) will be the same as the ID of the BSP currently loaded into the aBMA.  The necessity of this check is due to the process of preloading which may cause data in the aBMA to be partially rewritten.  The integrity check verifies the contents of the aBMA without having to load the BSP.  When an integrity check passes, the player will move into the District without causing the "Loading... done" message to occur.  If the integrity check fails, then a partial load of the BSP will occur to restore the aBMA's contents so that they match the data in the requested BSP.  This causes an identical loading message ("Loading... done") to the one displayed for a full BSP load.  

Preloading
As you approach a BSP loading point (district doors), you may trigger a preload.  When triggered, the game engine has predicted that you are about to request BSP data.  Some initial data for that BSP is then preloaded into the aBMA.  In the process, some of the data previously in the aBMA will be replaced.  Preloading the aBMA will cause BMA integrity checks to fail.  Preloading does not cause the BSP ID in the aBMA to change!

The crux of my hypothesis is that partial loading is flawed.  This partial loading bug is equivalent to Gothi's "loading glitch".  

Proof

Part 1: Integrity Checks.
  • Begin a new Mombasa Streets mission, beginning in District 05
  • Travel into District 08, noting the "Loading... done" message.
  • Make your way southeast through D08 toward the northernmost door that leads into District 06
  • Stay in the middle of the street that leads up the hill toward the district doors.  As you walk along this clear street (there's nothing to obstruct your progress) you will experience a moment of lag.  The preload has occurred.
  • Continue to the district doors and you once again receive a "Loading... done" message as the BSP data for District 06 has replaced the District 05 data in the aBMA
  • Enter D06, but stop at the first painted crosswalk. Allow the district doors behind you to close.
  • Turn around and go back into District 08.  Note that the loading message does not occur because the BMA check (both ID and integrity) passed.
  • You may repeat the process of walking to the District 06 crosswalk and back into District 08 as much as you want.  You will never receive the loading message when you re-enter District 08.

From this point, you may follow the steps to either Part 2 (the good stuff) or Part 3 (the normal behavior).

Part 2:  Partial Loading
  • Execute the steps outlined in Part 1: Integrity Checks
  • Return to District 06 and make your way toward the northernmost door into District 04
  • As you approach the fold-down roadblocks in front of the doors, you may notice the preload occurring again as there is a moment of lag.  As soon as it does, stop!
  • Optional: If you look to the northwest, you'll see the same glyphs I walked up to in my video.  It just so happens that they lie along the same preload proximity zone line as where you are now... hence my mistaking them as significant.  You do not need to look at these glyphs.
  • Making sure that you haven't hit a BSP loading point (i.e. you have not seen a "Loading... done" message), back up and return to District 08 the way you came in
  • As you approach the District 08 doors, you will now receive the "Loading... done" message because the BMA integrity check failed due to the District 04 preload.  You have just triggered a partial reload of District 08's BSP data.
  • Enter District 08 and notice that the infamous "Glyph Unlock" behavior (video) has occurred.

Part 3: Full Loading
  • Execute the steps outlined in Part 1: Integrity Checks
  • Return to District 06 and make your way toward the northernmost door into District 04
  • As you approach the fold-down roadblocks in front of the doors, you may notice the preload occurring again as there is a moment of lag.  Ignore it.
  • Walk up to the District 04 doors and you will receive the "Loading... done" message as the aBMA has been filled with the District 04 BSP data.  The BMA Check failed due to the ID check, since the requested BSP ID was for District 04 and the BSP ID in the aBMA was for District 08
  • You don't have to activate the district door switch to enter District 04 so long as you received the "Loading... done" message.  You can choose to enter District 04 or not; the results will be the same
  • Return to the doors into District 08 from District 06 and you will receive the loading message as the aBMA is fully loaded with the BSP data for District 08.  The full load occurred because the BSP ID in the aBMA was for District 04 which caused the ID Check to fail.
  • Enter District 08 and observe the normal state of doors, supply caches, etc.

Use
The "bump glitch" owes its name to two things:
  • You are required to pay attention to when preloads occur and stop when they do.  A preload feels like a "bump" in your player's motion due to the moment of lag it creates.
  • You conceptually "bump" objects out of a level by using this glitch

To use the glitch, follow this three step process:
  • Enter the district you wish to bump objects from (the "Bump District")
  • Leave that district and enter a second district which must be adjacent to a third one.  (e.g. You can't bump objects in D03 by using D00 as your second district...you have to use D04)
  • Walk carefully toward the doors to the third district, waiting for the preload "bump"
  • When the "bump" occurs, stop moving toward the doors to the third district
  • Return (preferably the way you came) to the Bump District.  "Bumpable" objects will no longer be there!

Now go bumping!  But don't forget to report your findings here!

Thanks to all of the SGP members for their support and resources.  It wouldn't have happened without you!  (Especially you, Gothi!)
« Last Edit: June 11, 2010, 15:49:03 by ColdGlider »
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ColdGlider

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Re: SGP: The Modified Gothi Hypothesis or "Bump Glitching"
« Reply #1 on: October 09, 2009, 05:29:37 »
WOOOOOOOOOOOO-HOOOOOOOOOOOOOOOOOOOOOOOOOOO!!!!!

Using the "Bump Glitch" I have entered the dark area in District 00!!!  It removes a lot of objects from this District, including the tall, dark security doors on the western edge!

AHHHHHH-HA-HA-HA-HA!!!!!!!!!!!!!!!

GO SGP!!!

Finally a dark area I can get to without having to be Tepec!   :P

I'll stop now so you guys can find some!  I have to work on a video...
« Last Edit: October 09, 2009, 05:32:39 by ColdGlider »
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ColdGlider

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Re: SGP: The Modified Gothi Hypothesis or "Bump Glitching"
« Reply #2 on: October 09, 2009, 12:58:38 »
The video is now available on YouTube!

Get bumping!
::o:-:-:o:-:o:o:o:oo:oo:-:oooooo:o:ooooooo:ooo:oooo:-:oooooo:o:ooooooo::

DeathIsTheEnd

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Re: SGP: The Modified Gothi Hypothesis or "Bump Glitching"
« Reply #3 on: October 09, 2009, 16:34:42 »
Went and tried this out, and just happened to be where you did it already. I wonder why they bothered putting a supply cache out there...
Now to find other places...

Rogue Sniper

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Re: SGP: The Modified Gothi Hypothesis or "Bump Glitching"
« Reply #4 on: October 13, 2009, 15:57:37 »
oh boy....this is going to take awhile to get used to bumbing.........but it will definately be worth it!
To stick or not to stick that is the question.

Scatcycle

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Re: SGP: The Modified Gothi Hypothesis or "Bump Glitching"
« Reply #5 on: December 16, 2009, 01:00:58 »
Went and tried this out, and just happened to be where you did it already. I wonder why they bothered putting a supply cache out there...
Now to find other places...
its there because the city is a mirror. Bungie got lazy so the city is the same backwards and flipped. that suplly cache is most likely on the other side of the city and reachable, and that is the mirror image.
I feel it