Charging and hindering movement

[Feragore]

I'm having some difficulty determining when a charge is allowed and what constitutes as 'hindering movement'.

PF SRD wrote:

You must have a clear path toward the opponent, and nothing can hinder your movement (such as difficult terrain or obstacles). You must move to the closest space from which you can attack the opponent.

If nothing can hinder your movement, does this apply to all effects that slow you down? For the main example, flying vertically cuts your speed in half even if you ascend only 5' out of your 60'+ fly speed. Is gravity hindering your movement or is it treated like spending extra squares as with diagonal movement?

How does this work with the Slow spell? It staggers you, forcing you to use the standard-action charge, but it also halves your speed. Are you able to charge or is the Slow spell 'hindering your movement'?

It's also curious when considering armor or a heavy load, which technically hinder movement from your base speed. But that clearly isn't a problem for charging otherwise the game would be fairly broken.

Or is it just the listed examples of 'difficult terrain or obstacles' and also effects that specifically state you can't run or charge?

[havok hiro]

I think the hinder your movement part just refers to difficult terrain, holes, fences etc. Most things that slow you down will specifiy if they prevent charging such as caltrops or anything that causes fatigue.

[Cry Jay]

Havok Hiro got it pretty much right on the dot.

Pretty sure if there's something that slows down your speed you can still charge, but things like holes and difficult terrain would prevent you like Hiro said.

CRB Under Combat wrote:

If you are able to take only a standard action on your turn, you can still charge, but you are only allowed to move up to your speed (instead of up to double your speed) and you cannot draw a weapon unless you possess the Quick Draw feat. You can't use this option unless you are restricted to taking only a standard action on your turn.

Couldn't find anything in there about encumbrance and effects on charge. Being encumbered just changes your base land speed doesn't prevent you on taking actions such as a charge. Check out the additional rules section. It really doesn't say anything about not being able to do actions, just says that base land speed is reduced and DEX or STR checks would come into play while doing skills.