(2026-03-26) Battle Init Data

Yo! Another update to a structure you know (and love?): BattleInitData, which as the name implies, holds the data needed to initialize a Castagne fight! Most probably didn’t use it much, but it’s been a cornerstone internally.

There is not much to talk about to be quite honest with you, as the ideas work the exact same, the interface is just better. It used to be an unwieldy JSON dictionary with a weirdo format, now it’s a properly reified object with a functional interface. Here’s an example where I create two players and their character, both have a 100 meter but the second one only has 1 HP.

// Assume we got config, player_1_scripts, and player_2_scripts properly handled before
let mut bid = BattleInitData::new(config);
let character_1 = bid.player().entity(player_1_scripts);
let mut character_2 = bid.player().entity(player_2_scripts);
character_2.entity_override("HP", MemoryEntry::Int(1));
bid.entity_override("Meter", MemoryEntry::Int(100));

As you’ve seen, it is simpler to build, and the previously available functions are there. Overrides allow you to change a variable from the character at creation, and you can set them up to be inherited. As such, the Meter override here was set at the root, so it applied to all entities defined in this BID, while the HP one was only done to a single entity. You can override global, player, and entity variables, as well as create entities with no player parent.

This is still a work in progress, as I’m focusing first on key functionality there. The new idea is that known data can be set more easily in general when the engine knows about it, with simple functions. Here’s an example of a new functionality: instancing subentities directly:

bid.player().entity(scripts).subscript(fireball_subscript_id)

This is honestly fairly low priority compared to other tasks once that the basic functionality is there (some overrides don’t currently work because there’s no player memory yet for instance). It’s needed to set up fights in the editor and game, but at the moment only the first is needed to get started with the engine (as you remember with my priority list). Still, are some planned / potential functionalities:

• First of all, there is going to be a host engine interface. That example was in Rust, but you’ll be able to have a very similar interface from within Godot.
• The flow module will be able to handle “standard” variations of this. An example you already know is the fighting variation, which just gives you a 1v1 with potentially multiple characters.
• An idea I’m evaluating, is the ability to save a state to a BattleInitData, which would allow to store state on disk. This could be REALLY strong for editor tools.
• Another idea in a similar way, is the ability to add BattleInitData DURING a fight. With proper management (keyword: proper), this could allow complex worlds and situations, which would be quite interesting for the more platforming focused cases.
• Another one that’s linked to both, is the ability to reference existing HostStructs or similar from within. I’m not sure yet of what this would imply, but the idea is to be able to integrate Castagne into game flows better, like starting a fight from an RPG overworld seamlessly. We’ll see when I need it I guess lol, that’s real low prio compared to actually making stuff work.

Next up is multiple file loading for CASP files, as well as Editor control there. It’s time for the Base CASP to get a tune up, and that would already cover most of the prerequisites for the engine!

(2026-03-24) Physics engine okay!

Big milestone! I’ve advanced the whole engine flow enough so that we now have both physics and attacks working! They kind of go together.

First off: Physics. The new engine is more advanced than the previous one, as it’s made to handle more colliders and both 2D and 3D at the same time. 2D colliders are compatible with 3D and vice-versa, although it’s not what I would recommend to use lmao

At the current moment, it’s at mostly parity with the previous engine. While I could finish it right this week, I know people will want to use the new Castagne for the upcoming Indie FG jam this april, so I’ll be postponning it for a bit to focus on the editor.

Something that is of note here is the interface: the collider functions have changed. While I know this adds additional work for the porting of projects, after tests I’ve seen that this way is a bit better.

• Colbox and Hurtbox now work with an horizontal center, and a base and height. This is a better way to adjust colliders that are close to the character imo. Colbox(0,100,0,500) (equivalent to Colbox(100, 500)) will produce a box going from -100 to 100 horizontally, and 0 to 500 vertically, so it’s a simple way to add one to characters.
• Hitbox now works with width and height from the lower back corner. Hitbox(0, 100, 0, 500) (equivalent to Hitbox(100, 500)) will produce a box going from 0 to 100 horizontally, and 0 to 500 vertically. It reflects the more forward-facing nature of hitboxes, and thus allow faster set up.

I’ve set it up this way because it also becomes easier to move colliders around from code, as instead of being coordinates it’s now origin and dimension. This makes operations easier, except shrinking a collider forward which is the same difficulty as before. Do note that the order of parameters stays coherent: it’s dimension by dimension, and the shortcuts are (width, height) and (width, base, height) for each function, covering most cases.

This is not fixed in stone yet, so you can discuss it on the forum. Something to note is that I’m planning on adding drag-and-drop in the editor for these, so it should be easier to set up once the editor is more featured.

Some changes on the Attack module front too, although this one is quite tamer. It’s just a slight rework of the attack events, which work as such:

• At the start, OnAttacked is called on the defender. This is the first event, where most attack overrides will happen. This is before the blocking computation, so you can potentially decide to get hit or not, which is a new ability.
• After that, either OnAttackHit or OnAttackBlocked is called on the attacker depending on the result. The rest of the overrides happen here, and that’s where the attacker gets his meter and whatnot.
• Finally, OnGetHit or OnBlocking is called on the defender. This is where you apply the changes to HP and the like.
• In the case of a clash, only OnAttackClashed is called on both clashers.

All attack events share two properties: the target is the opponent for the attack, and Attack. allows you access to the current attack instead of preparation. This is intended to allow more flexibility in case of multiattacks and to enable more behaviors. Do note however, that the engine doesn’t store recieved/inflicted attacks anymore so you can’t refer to them outside of these events.

There’s more upcoming changes, although this post is long enough and I’m deciding on the details. Something to note, in this whole rework, is that the engine now makes more assumptions about your game, one of the key ones being the ground. The previous Castagne didn’t really care, but this one assumes that being grounded or airborne is a fundamental caracteristic of the game. I like that because you can ignore it if you don’t care, but it allows better integration, which really helps many cases. This is a throughline of the updates.

My next step is to advance the flow module, and to advance the editor workflow. I want the engine to be ready for the jam, although if you want to use it you’ll need strong basics with the previous one. Please get in touch, as this will probably be a closed beta, as it has enough caveats that I don’t want it available without supervision, and instead focus on a polished release. See you next update!

(2026-03-21) Forum Launched!

Hey hey! So up until now, the Castagne community was a bit spread around, but especially on Discord. This isn’t always the best for storing information long-term and having transparent discussion, but it was good enough for a while. However, now that Castagne has grown, it’s time to migrate to a proper forum!

You can find a couple things on the forum already:

• You can ask for help! There’s a support category where people can help each other, and answered questions are marked!
• You can post and read tutorials! Share your own knowledge there!
• Share your games!: Create a thread for your own game so that progress doesn’t get lost! You can also find likeminded people to work with!
• Castagne Development!: You can discuss all these progress updates I’m doing there! Threads are created quickly after publication, and you can also talk about improvements to Castagne.
• Real-Time Chat: You can still do lightweight discussions there! There’s also more general categories on the forum.

GO TO THE FORUM

The Discord will still exist, but I’m going to focus more and more on the forum as time goes on. The forum is going to be the one pushed forward on the website from now on, and there are integrations from the forum to discord.

Little extra info: at the moment the forum is using DiscourseID, since my mail is blocked by gmail (probably previous owner of the IP doing weirdo stuff with it), but I’m hosting it on my own server. When I have the time to properly investigate and fix this, I’ll add the option for local accounts.