The Quadrant Glitch is a camera-related glitch that confuses future transitions.
This glitch is caused by a conflict between 2 movement functions attempting to update Link's position at the same time. All but 1 of the methods involve releasing a sword spin. With sword spins, the quadrant glitch becomes armed and active when Link releases a spin attack on the same frame that he crosses a quadrant boundary line. As such, the glitch is frame-perfect and usually pixel-perfect as well.
In Desert Palace and Desert Palace only, the glitch can also be performed in the first room or the section of it right above. Taking damage that pushes Link across the horizontal boundary line while at the edge of the screen transition will stop his movement. Taking the screen transition as this happens will cause a conflict, resulting in the glitch being armed. This room is the only place in the game where a quadrant boundary and a supertile transition intersect on a walkable tile.
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 is usually too late to tell. The best course of action for an unintended quadrant glitch is always to mirror immediately after it is noticed. Having the glitch armed is very apparent after the first transition, which will wrap the screen multiple times.
From a technical standpoint, the main tell is in a camera array beginning at
$0600. As an example, here is the memory watch for the quadrant glitch in the Desert Palace cannonball room. Take note of the behavior of the highlighted addresses:
|Unglitched 1 pixel down||7E060_||00||0F||00||0E||10||0F||10||0F||00||0B||00||0A||00||0B||00||0B|
In Any% (NMG, No S+Q), there are a few places where the quadrant glitch can reasonably happen to a player following the proper route with normal behavior:
- Thieves' Town Hellway (in general, you should be heading straight to the next room; however, to understand where the boundary line is: if you let the conveyor push you to the top of the second statue, you are on the top-most pixel of the lower quadrant)
- Moldorm 2 (using the bottom concave hole as a guide, boundaries are in its exact vertical center, and right below the wedge graphics)
For a player using less-familiar tech, it is also reasonably possible to glitch in other rooms:
- Escape (with very bad movement and early detection, it is technically possible to clink and spin across the boundary at the first key guard -- situated exactly between the statue and the chest)
- Ice palace conveyor room (don't attempt to spin attack)
- Turtle rock (only the first big room has enemies to kill while on a somaria platform; however, they should be killed with beam attacks, if at all)
- Ganon's tower end of teleport maze (don't kill beetles; head straight to the next room)
- Ganon's tower after wizzrobes 2 (don't even kill the guards, just head straight to torches)