MMBN6 encounter checks

MMBN6 has an internal step counter that increases every frame that you're moving.
- If you're walking, it goes up by 1 per frame.
- If you're running, it goes up by 2 per frame.
- If you're on a staircase, it always goes up by 2 per frame EXCEPT if you have AutoRun or SlipRunner active and are not holding the B Button; in that case it goes up by 1 per frame.

AutoRun (MMBN5):
- Moving without B Button moves you at run speed, but step counter increases 1 per frame, even if you're on a staircase!
- Moving with the B Button also moves you at run speed, but step counter increases 2 per frame.

SlipRunner (MMBN6):
- Moving without B Button moves you at run speed, but step counter increases 1 per frame, even if you're on a staircase!
- Moving with the B Button also moves you at run speed, but step counter increases 2 per frame.
- Pressing the B Button while moving causes you to slip. This moves you faster than run speed, while the step counter increases 2 per frame.

Step counter:
- At any point while you're not in a special animation, an encounter check can occur if the difference between the "current step counter" and the "last encounter check step counter" is at least 64.
- Upon entering a map or exiting battle, the "last encounter check step counter" is reset to 0.
- Slipping with SlipRunner counts as a special animation and will block any encounter checks from happening until you hit a wall or object. However, if you slip into a warp or loading zone, no encounter check will occur.
- When the step counter difference is at least 64, the "current step counter" will be written to the "last encounter check step counter" and an encounter check will occur.
- If the step counter difference is 128 or higher, still only a single encounter check will occur. This normally only happens when you slip for a long distance.

No encounter event:
- Some comps have events where no encounters occur. For instance when a firewall is active in Robot Control Comp, when a shark is chasing you in Aquarium Comp, or when you're on a cloud in Mr. Weather Comp.
- What happens in these cases is essentially, all encounter checks are disabled until the event ends.
- Additionally, when the event ends, the "current step counter" is reset back to the value of the "last encounter check step counter".
- So effectively, this is slightly more beneficial to the player than simply not increasing the step counter as this will also reduce the step counter slightly when the event ends. Presumably the goal of this is to prevent a scenario where an encounter is thrown at you almost immediately when the event ends.

Encounter check:
- Divide "current step counter" by 64. If 17 or higher, set to 16.
- Get the encounter chance curve for the current area.
- Use step counter / 64 as an index in the encounter chance curve to get the current encounter chance.
- If encounter check passes, proceed to battle selection.

Battle selection:
- If LocEnemy is active, 50% chance to select the same battle that is being searched.
- If no battle selected yet and a 1/12 check passes, select a Rare Virus battle in the area if the conditions are met.
- If no battle selected yet and element search is active, select a random battle in the area with that element.
- If still no battle selected yet, select a random battle in the area.
- If SneakRun active and you have 100% run rate in the found battle, skip the battle. When this happens, both the "current step counter" and "last encounter check step counter" are reset to 0.
- Otherwise, start the selected battle.

Encounter bug:
- Bugging SneakRun or an element search NPC will give you an encounter bug. This causes the game to always use the special bug encounter chance curve regardless of which area you're in.

Encounter chance curves:

Dungeon Comps: curve 6
	[ 0/32,  0/32,  0/32,  0/32,  0/32,  0/32,  0/32,  0/32,  0/32,  0/32,  0/32,  0/32,  0/32,  0/32,  2/32,  6/32, 12/32]

Internet/Undernet, Pavilion Comp: curve 5
	[ 0/32,  0/32,  0/32,  0/32,  0/32,  0/32,  0/32,  0/32,  1/32,  2/32,  3/32,  4/32,  5/32,  6/32,  8/32, 10/32, 12/32]

- Graveyard/Immortal, HomePages, small comps: curve 3
	[ 0/32,  0/32,  0/32,  0/32,  0/32,  1/32,  2/32,  3/32,  4/32,  5/32,  6/32,  8/32, 10/32, 12/32, 14/32, 16/32, 18/32]

- SneakRun bug: curve 0
	[ 0/32,  0/32,  6/32,  7/32,  8/32,  9/32, 10/32, 11/32, 12/32, 13/32, 14/32, 15/32, 16/32, 18/32, 20/32, 26/32, 28/32]

All curves (including unused):
0	[ 0,  0,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 18, 20, 26, 28]
1	[ 0,  0,  0,  1,  2,  3,  4,  5,  6,  8, 10, 12, 14, 16, 18, 20, 26]
2	[ 0,  0,  0,  0,  1,  2,  3,  4,  5,  6,  8, 10, 12, 14, 16, 18, 20]
3	[ 0,  0,  0,  0,  0,  1,  2,  3,  4,  5,  6,  8, 10, 12, 14, 16, 18]
4	[ 0,  0,  0,  0,  0,  0,  1,  2,  3,  4,  5,  6,  8, 10, 12, 14, 16]
5	[ 0,  0,  0,  0,  0,  0,  0,  0,  1,  2,  3,  4,  5,  6,  8, 10, 12]
6	[ 0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  2,  6, 12]
7	[ 0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0]
Some other games have different curves per stage or area. For instance in MMBN1, Oven Comp has a higher encounter rate than other dungeons, whereas Waterworks 5 and Power Plant have a lower encounter rate. I haven't checked in the other games, though.