How to implement moving platforms in a 2D platformer!

Here's a look at how I implemented 2D platforms in my NES game, Super Sunny World!
I'm not sure if this is the best way, but it's the way I've found works best for me, and is fast enough to run on the NES.

[@MattHughson]

A couple things that might not be clear in the video: 1) The different phases I go through all happen in a SINGLE FRAME *before* rendering. 2) The Update logic and the Rendering logic need to be separate, so that all of the "corrections" shown here happens BEFORE the screen is drawn.

[@Satorl]

finally someone explains this in an understandable way!

[@AidinZolghadr]

Another lifelong sworn enemy of mine is ladders, would love to see how you would handle ladders. Like how to land in middle of a ladder and catch it, etc.

[@AidinZolghadr]

How would you handle slopes? I think it's a 10-hour long video haha. Very complex.

[@kennyryan4173]

Would be nice if you also mixed in the platforms that drop a second after you land on them. Makes for more of a challenge.

[@MattHughson]

I actually just implemented that a few days ago!

[@theboy181]

I want to be your best friend! am I too late? With the flickering line under the game and before the menu, is it possible to hide it better ? anyone figure out a creative way yet?

[@MattHughson]

Yes it can be hidden. It's very timing specific so I don't want to dig into it until the game is more locked down, and i know the frame timing won't change anymore.

[@akaNekete]

Thanks for the explanation. Would it be possible to have one video about how you managed the "cutscenes" in your games? (like the ones in “Witch N Wiz” -that are gorgeous-). Thank you 🏖🌞

[@MattHughson]

Yah, I could! Although, they are pretty hacky! Most of the time it's just a giant hard coded state machine, hand coded to do what I want. I don't have any tools for editing etc.

[@akaNekete]

@@MattHughson thanks anyway for giving it a thought and for your channel 👍

[@esotericsean]

I assume the moving platforms are sprites?

[@MattHughson]

That is correct.

[@AidinZolghadr]

I honestly don't like outside force moving player freely because for example when an object is attached to the player, it has no idea such thing is happening and may lose a frame, same "order" problem. But I think you'd tackle it in a similar way.

[@AidinZolghadr]

How the moving platform "know" which objects it's colliding with? Do they get registered when they touch it?

[@MattHughson]

They simply do an box-to-box collision check. In my case, I update the player first, so I actually cache the platform that play is touching (if any), and then in the update for the platforms, they can quickly say "am I THE platform the player is touching right now" before doing the "move the player" code. However, it could also be that each platform does a collision check with the player in their own updates (prior to moving).

[@AidinZolghadr]

OMG you went above and beyond and made a video about our chat :)) you're such nice person!

[@MattHughson]

No problem. I think it's a great topic to share!

[@AidinZolghadr]

What happens when platform is moving up and player jumps, does it add speed of the platform to it's jump speed? Because if platform is moving fast and player jumps, it would pass the player. (Unless you have CCD!, btw, do you?)

[@MattHughson]

In my game it does not. It could thought. I think the way I would implement that is rather than having the platform "teleport" the player around, it would set the player's "velocity" to match the platform, so that if the 2 separate, the momentum of the player would be maintained.

[@MattHughson]

And yes, I do have the problem that if the player is moving faster than the "width/height" of the platform, they can pass through it. This isn't an issue in reality though, due to the constraints of the game. This is not isolated to moving platforms either; it could happen on a static floor if the player is moving faster than 16 pixels per frame.