Quadrant Glitch

A quadrant glitch or QG is a camera-related glitch that bugs future transitions. Because of it's effects on screen transitions, it's considered a subset of transition glitch. It can be used intentionally by the player to make a transition behave differently, but it's also notable for being one of the transition glitches that can accidentally occur in situations where the player doesn't want it.

Mechanics

Quadrant glitch is caused by either a conflict between two routines attempting to update Link's position on the same frame, or from two routines disagreeing on where Link should end up.

Quadrant boundary lines exist every 256 pixels on both axes. Supertiles are 512 square pixels in area. When viewing coordinates, the quadrant line is crossed when the last two digits of Link's coordinates go from 0x00 to 0xFF, or vice versa. Link's quadrant is split into two variables: one for indicating Link's horizontal quadrant ($A9 in memory) and one for indicating Link's vertical quadrant ($AA in memory). Two routines conflicting and updating Link's quadrant twice happens when a sword spin is released on the same frame as another action that moves Link across a quadrant boundary, such as:

• Recoiling off a sprite (e.g. Moldorm, beetles, bumpers)
• Moving with a conveyor
• Moving with a somaria platform

It is also possible for one routine to believe Link should cross a quadrant boundary and another routine disagrees. This can be done by attempting to move diagonally across a boundary line at the same time a transition is triggered while taking damage or using a medallion. For practical purposes, this can only be done in Desert Palace in the caged-off leever area just north of the lobby. This is the only normally accessible location where a quadrant boundary and a non-door transition intersect. Technically though, this version of quadrant glitch can be done in EG as well.

Practice hack watches

In the v15 practice hack, the RAM watch named Quadrant will show the current quadrant the game thinks Link is in as well as the correct quadrant you are in, based on your coordinates. Link's current quadrant also controls the camera scroll boundaries stored at $0600 in the memory. These can also be viewed in the practice hack with the UW Camera X and UW Camera Y line watches. In short, these control the maximum and minimum positions the camera can scroll to on each axis. These boundaries are controlled by the current quadrant variables and the room layout variables. These also get out of sync when quadrant glitches occur, and they can be noticed by the obvious fact that the camera scrolls too far at screen edges.

Depending on the direction of the quadrant glitch (north-south or east-west), all future transitions in those directions will be broken. While technically possible to fix with other major glitches, it's usually too late to tell. The best course of action for an unintended quadrant glitch is always to mirror immediately after it's noticed. Having the glitch armed is very apparent after the first transition, which will wrap the screen multiple times.

NMG

Quadrant glitches aren't allowed in NMG runs, but it's possible to activate the glitch unintentionally. While it's technically possible to "fix" a quadrant glitch, it would require other major glitches. The best course of action for an unintended quadrant glitch is always to mirror immediately after it's noticed. Having the glitch armed is very apparent after the first transition, which will wrap the screen multiple times.

There are a few places in the Any% NMG No S&Q run whee a quadrant glitch can reasonably happen to a player following the proper route with normal behavior:

• Thieves' Town hellway
• Moldorm 2

For player using less familiar tech, it's also reasonably possible to glitch in other rooms:

• 1st key guard in Hyrule Castle
  • with poor movement and early detection, it's possible to clink and spin across the boundary in this room, which is situated exactly between the statue and the chest
• Ice Palace conveyor room
  • don't attempt spin attacks
• Turtle Rock somaria platform rides
  • don't attempt spin attacks—they're slower and less effective than using sword beams anyway.
• Ganon's Tower final telepad maze room
  • fighting the beetles risks a quadrant glitch—they should just be avoided
• Ganon's Tower foosda bridge (the falling bridge after the conveyor wizzrobes room)
  • don't try to fight the guards, just head straight to the torches room)