Wind and swimming updates

[biggeryetbetter]

This PR includes an overhaul of wind and swimming physics.
Included changes:

• Player doesn't jitter in certain scenarios with wind
• No skidding noise in wind.
• Player is not slowed down when they work with wind.
• Most flying enemies can now interact with wind
• A "Current" variant of wind that does not affect Dive Mines.
• Swimming feels looser
• Wind acceleration and speed is now part of the Physic class for convenience.

Most levels should be unaffected by these changes, however levels that rely on certain swimming quirks may break.

[Rusty-Box]

A issue that does still persist is that when the wind is set to values (I believe) below Tux max. walk/run speed, Tux will not be moved by the wind when standing still, stuck in his run animation.

Also, I feel that wind should always affect things when they are in their zone. Right now if you don't jump it will not affect you at all, even though you are clearly inside the wind zone.

wind.mp4

[biggeryetbetter]

I have made several changes to the wind physics process that seem to have fixed these behaviors. I've also added a prototype "current" that does not affect dive mines. I would like some clarification about what you mean in #2592:

You have better control within the current for better navigation and correcting

By this, do you mean faster acceleration/deceleration?

[Rusty-Box]

So the thought behind the current was that (since it is underwater) it can be used to suck/push Tux into an area. However, Tux should be able to swim against the current if it is not too strong. Now that should probably apply to both the current and wind. Main difference is that the current type would have different particles (i.e. bubbles) to better fit the aquatic theme.

[Rusty-Box]

Somethig I noticed with the "Current". It is very hard to fight it. Especially with an acceleration of 100. You would expect setting the speed of wind lower than Tux's swim/boost speed, he'd still be able to slowly go against the current. However, I seemingly get force-halted by the current even thought techincally Tux should still be able to swim through (obviously slower). It lets me swim for a short moment before halting all my progress, even when oosting which is moves very fast! Even with an acceleration of 10.

current_wip_issue.mp4

Also, make sure to have the "Current" particles fade out rather than suddenly disappearing in an instant.

[Rusty-Box]

I would not be suprised if something similar applies to the normal wind as well

[biggeryetbetter]

I'm admittedly a bit stuck on this issue. While the normal wind seems to be working correctly, it seems that in water, the acceleration from current is still vastly overpowering that from swimming. Unfortunately I'm not really sure how to fix that without also altering how swimming works- any ideas would be appreciated.

[Rusty-Box]

Unfortunately I'm not really sure how to fix that without also altering how swimming works- any ideas would be appreciated.

Altering swimming in what way? Swimming is still a fairly "unpolished" mechanic so alterations are still legitimate as long as they improve it. So depending on how would have to alter it, you might be able to go through with it.

[biggeryetbetter]

Alright, I've tried tweaking swimming to actually work with wind. Let me know what you think. Boosting in particular seems to sometimes create large radii on turns which might need to be fixed.

Also, how can I make the water bubbles fade out?

[Rusty-Box]

Found a couple bugs:

• Walking through wind and standing, Tux gets pushed much weaker as when he jumps afterwards

inconsistent_wind_push.mp4

• When underwater Tux will attempt to always move left when letting go of the directional keys.

swim_bug.mp4

• At higher acceleration, around 100 (default value) but also noticeable aroud 50, Tux begins kinda jittering in a current and also somewhat stop an go when at higher speed wind

wind_current_jitter.mp4

---

It also seems that the wind affect Tux statically, i.e. instead of his speed accelerating or decelerating "smoothly" it changes instantly. Atleast that's how it felt to me. It should ease into the new faster/slower speed to make the transition more smooth. This seems to apply to both wind and current, if that is truly what is happening, maybe I'm mistaken here.

[biggeryetbetter]

I can confirm the first and third bugs but I'm not able to recreate the second one. Can you upload the setup that is shown in the video?

Another bug: Pressing the down arrow rapidly while moving into fast wind somehow allows you to go through easier. This is caused by some stuff around line 1586 of player.cpp and I don't know what they are supposed to do so I won't touch them.

[Rusty-Box]

Can you upload the setup that is shown in the video?

This is the level I tested and discovered that bug:

wind_test_level.zip

[Rusty-Box]

More bugs I found:

• Buttjumping in downwards moving wind breaks the animation, i.e. Tux gets stuck in his buttjump an/or stomp animation after touching the ground.
• Tux cannot duck when in wind that goes downwards

[Rusty-Box]

I also noticed that when you swim in the Current and you move in the direction it goes, you kinda seem to break the speed at which it is pushing you, like you get a bit slower than when you just get pushed without moving yourself. This might also apply to normal wind. Not sure on that. I usually notice it best while swimming.

[Rusty-Box]

Okay I keep finding many more bugs - sry 'bout that :D

So apparently, Dive Mine is still affected by currents but also when they leave the current/wind area they keep on going, never stopping. Also getting pushed underwater is still somewhat jittery. Feathering help a little bit but overall needs a much higher value than normal wind to be smoothed out fully, for the most part.

Speaking of feathering, so idk if I fully get what it does specifically but the best values I've seen with it seems to be around 350? Can shed some more light on what it does exactly because with default value of 16 it looks horribly jittery

[biggeryetbetter]

Don't worry; that's what open-source is all about. I haven't done a particularly good job testing each change, to be honest.

Also, the way feathering works is that it calculates how far the center of your hitbox is from the edge of the wind area (in pixels), then divides it by the feathering distance and clamps it between 0 and 1. It wasn't introduced to fix the jittering (that is caused by friction) but rather the fact that tux would keep "bouncing" off the edge of strong wind instead of pushing up against it like you might expect.

My main problem with how it works right now is that if you put wind in a tunnel, like in the test level you showed previously, the top and bottom edges of the wind will have feathering, even though this makes no sense inside a tunnel.

Also, I found out that I was calculating m_wind_velocity (should actually be m_wind_acceleration) completely wrong which seems to have been what was going on when you said

It is very hard to fight it. Especially with an acceleration of 100. You would expect setting the speed of wind lower than Tux's swim/boost speed, he'd still be able to slowly go against the current.

I will keep attacking these issues and hopefully we can get this to work soon!

[Rusty-Box]

Any further progress on this? Just checking :)

[biggeryetbetter]

Not really as I have again been busy with other things. It seems like the cause of the weird jittering bug is that wind only collides with tux every few game ticks and adds velocity, in between which, friction causes tux to suddenly slow down. That is what I have been stuck on currently.

[biggeryetbetter]

Alright I think I got the jittering issue fixed finally... Sorry that took awhile. Let me know what you think and of any bugs you find.

[Rusty-Box]

Swimming feels now quite heavy. Not the worst thing in the world, I definitely don't hate the idea. Anyway, back to wind:

There still persists the issue that when getting pushed by wind and Tux standing on the ground he is getting pushed much weaker than when you are mid-air which feels rather off. I also agree with Daniel that the acceleration is quite weird as well. To get a descend upwards wind I had to set it to 2000, for example. Downward facing wind meanwhile doesn't seem to have any effect on you at all, even at 2000 acceleration.

[biggeryetbetter]

I've made a change that was suggested by @MatusGuy in Discord a month or so back which was to put wind logic with the Physic class. Team members should let me know what they think.

There still persists the issue that when getting pushed by wind and Tux standing on the ground he is getting pushed much weaker than when you are mid-air which feels rather off.

To be honest, I'm not really sure how to fix this. I would say just keep it as a sidenote for now.

I also agree with Daniel that the acceleration is quite weird as well. To get a descend upwards wind I had to set it to 2000, for example. Downward facing wind meanwhile doesn't seem to have any effect on you at all, even at 2000 acceleration.

I can understand this, however it aligns much better with how physical values like speed and acceleration are handled within the code. Nonetheless we do already multiply sector gravity by 100 in the Physic class, so I decided to apply the same logic to wind. Levels like A Leaf In the Wind sort of work like they used to.

[Rusty-Box]

Could you please resolve the merge conflicts on the PR so we can get builds for testing?

[Rusty-Box]

Swimming has gotten rather worse here, or rather swim boosting. It is very sluggish now, you can't build up speed anymore properly for swim jumping. I like how it eases into faster speeds but the execution isn't so great.

The max speed should be reached much faster but still ease into it, turning also needs to be made just a bit tighter. I'm also unable to push against currents of weaker strength when swim boosting even though technically Tux should be able to swim through. This might be linked to how slow you build up speed when boosting right now.

[MatusGuy]

To be honest, I'm not really sure how to fix this.

Have you taken a look at the ground movement manager? It could possibly be related

[Rusty-Box]

Swimming feels much better again. Still the issue of being unable to swim against a weaker currents is present but the rest seems great 👍

[Rusty-Box]

Hold up, is Tux swim boost faster? I'm testing out some levels and he zoomin'. Maybe a bit too fast. It's like he keeps gaining speed underwater. I keep ramming into stuff :D

[swagtoy]

I haven't tested this PR, nor do i like it's description, because I have a question regarding the swim updates. Is it directional? Meaning, does the turn still happen instantly or is there a bit of slowdown now when turning in the water?

I think an issue i've noticed with the old swimming is that turning is too easy, it's much like the frog suit in the mario games. I always wished there was some turnaround 'lag', where the player's turning is clamped to where they want to go (up, down, left, right). This creates an immersion of realistic swimming and also makes swimming feel more challenging (not just flying in midair sort-of)

Not to mention, I would really like if swimming wasn't as fast as it is now.

[Rusty-Box]

I haven't tested this PR, nor do i like it's description, because I have a question regarding the swim updates. Is it directional? Meaning, does the turn still happen instantly or is there a bit of slowdown now when turning in the water?

With this PR turning has gotten a bit looser now, though Tux is rather fast which causes some issues. Especially while boosting.

Not to mention, I would really like if swimming wasn't as fast as it is now.

I wouldn't be against fine tuning a couple values here (as long as swim boosting remains on the faster side for swim jumping mostly) though not sure if required for this PR specically as the main focus is wind.

[swagtoy]

With this PR turning has gotten a bit looser now, though Tux is rather fast which causes some issues. Especially while boosting.

Can you show a video of you turning?

[biggeryetbetter]

Here you go:

2024-10-30.19-52-14.mp4

[Frostwithasideofsalt]

One thing i wish would be added back to this pr's swimming is the ability to jump out of the water with a lot of speed after dropping into the water with a lot of speed.

as.mp4

it let to a lot of cool and fun speed-running opportunities. currently when you drop into water from a high place you just loose all your momentum. I dont feel like something like this is required for this PR, but it would be really nice if this got added to this Pr, because it would be a shame to see this go.

[Rusty-Box]

Swim and swim boost speed is still way too high. Very uncontrollable in narrow water areas.
The rest seems good I think.

[Rusty-Box]

Definitely getting closer. While normal swimming is better now and boosting technically feels much better to control, an issue that arises is the jump height you gain from jumping out of the water. It is very low. Previously you used to be able to jump about 4-ish tiles. Now it's barely 2. Adding a little bit more speed for boosting, it may run the risk of making boosting uncontrollable again. You could try increasing the boost speed to 500? Not sure how much that will fix it.