Scaffold Level Editor

https://blog.littlepolygon.com/posts/scaffold/

by mwkaufma • 1 year ago

137 29 1 year ago

blog.littlepolygon.com

mwkaufma11• 1 year ago

A whistle-stop tour of some game-engine collision/pathfinding background, how modern engines work, how old engines work, and how I'm applying a mixed-approach in my game.

charlietran• 1 year ago

Excellent article, and I appreciate how you gave an overview of solutions that didn't make sense for you but were otherwise important to know about.

Could you expand on how your pathfinding works for both ground-based and flying enemies? I've been trying to wrap my head around how to handle this on my own game, and trying not to invent a wholly separate solution for enemies than can avoid obstacles vertically.

mwkaufma11• 1 year ago

The scaffolding is built from convex volumes, and I know which cuboid faces are "walls" and which are "windows" so I link the windows into a graph where the shared-faces are waypoints and do A*, using straight-line distance as the cost function.

Big obstacles are just built from the scaffold itself, and small obstacles are avoidable by just doing "whisker-traces" to veer around them (the navigation path is a movement hint used to calculate accelerations, not followed strictly).

squiggy22• 1 year ago

I have such an appreciation for write ups like this. Reminds me I'm not a real programmer at all.

Esras• 1 year ago

Thanks for sharing! I was thinking how this is a good example of the kinds of things that you can do with a game engine that already exists, as opposed to having to write everything yourself.

Also a nice mention of octrees' use outside of voxels.

rdw• 1 year ago

Thanks, Max! I've personally never been able to wrap my head around BSP; I appreciate your diagrams explaining everything, and I am optimistic about the new engine. It's crazy how much faster it can be; really drives home how much extra stuff Unreal is doing that your game may not need.

LarsDu883• 1 year ago

Isn't this kind of like simply putting the data structures from the first Unreal Engine (which I believe used BSP), into the latest one? For the game you appear to be building, this appears to be rather unnecessary, even for authoring purposes. Even the Nintendo Switch 1, which is being phased out, might not necessarily benefit enough performance-wise to overhaul these core systems.

mwkaufma11• 1 year ago

It's not a BSP, it's volumetric data (this is in the actual article). Just off the bat I get aerial navigation "for free" without having to hand-place regions, and a secondary collision-query for bullet-hell that's much faster than Chaos, which was a huge perf regression in UE5 from PhysX (which already wasn't great).

Additionally, there's productivity + rapid iteratoin. Trying to build interiors with Unreal's built in drag-out-an-actor-at-time interface is too laborious, and the built-in automations (Construction Scripts, Blutilities, PCG) are impedance-mismatched for constructing interiors quickly.

LarsDu883• 1 year ago

How is it that you are running into cpu limitations for raycasts in a bullet hell game with UE5 to the extent you built this?

I wrote a VR game that has hundreds of bullets running at 72 fps on Quest 2. Never went multithreaded and never actually encountered FPS drops due to CPU limitations

LarsDu883• 1 year ago

I don't think I quite understood what you are trying to accomplish that is distinct from what 90s BSP engines like Unreal 1, Quake 2, and Source were doing?

Are you trying to do convex spatial partitions for 3d pathfinding in the air?

I did an indie VR starfighter game Rogue Stargun (https://roguestargun.com) and quite honestly intermittent navigation raycasts from the enemy ship AI is sufficient for this sort of stuff.

The bullets all run on the main thread on mobile hardware and so does all the AI. It's not optimized and I have yet to witness CPU bottlenecks being the main cause of frame drops.

Your game looks simple enough and is on the PC platform... I suspect you may be optimizing for the wrong thing.

dcrazy3• 1 year ago

UE still has BSP for blocking out levels: https://dev.epicgames.com/documentation/en-us/unreal-engine/...

mwkaufma11• 1 year ago

It's a bit legacy, since it's just used to tesselate PhysX/Chaos trimesh collision, rather than doing true BSP collision in game :/

enbugger• 1 year ago

I was always inspiring the level editor in Cube 2: Sauerbraten (http://sauerbraten.org). This seems like an alternative to BSP approach which was more popular at the time. But I think this game's octree-based solution has more potential than just the render and raycast logic implemented in the engine. You could potentially make the entire level fully destructible and keep it optimized at the same time. The level building was also fun when I was teenager. No game allowed to edit levels with other players connected to the server and that was working in 2004!

mwkaufma11• 1 year ago

That's a cool reference, thanks for showing me. Similar energy to Q1K3 https://phoboslab.org/log/2021/09/q1k3-making-of

aschearer• 1 year ago

Great write up, very interesting. Shame y’all couldn’t get funding even after Day of the Devs! Hang in there, game looks cool.

mwkaufma11• 1 year ago

Last year was rough for indie funding because of interest rates. Luckily, Absolute Nothing Economically Destabilizing Is Happening This Time (O___o).

OccamsMirror• 1 year ago

This is very cool. I would pay for this.

mwkaufma11• 1 year ago

Wishlist! https://store.steampowered.com/app/3038700/Nightshift_Galaxy...

shadowgovt• 1 year ago

Those are some good missile effects right there.

dcrazy3• 1 year ago

I created my HN account to comment on the post announcing the release of the Descent 3 source code last year. So of course I immediately recognized the similarity to Descent 1 and 2’s cube-based level design, and was pleased to see the screenshot of DLE. :)

keyle• 1 year ago

Note that there is also TrenchBroom [1]. An editor which you can then use to create levels and import them in UE4/5 [2], including textures and collisions.

[1] https://trenchbroom.github.io

[2] e.g. https://www.youtube.com/watch?v=41HZzy-nJDU

klaussilveira• 1 year ago

TrenchBroom caused a renaissance in Quake 1 mapping community, bringing tons of new mappers:

https://www.quaddicted.com/

As well as dumptruck_ds tutorials:

https://www.youtube.com/watch?v=gONePWocbqA&list=PLgDKRPte5Y...

Scaffold Level Editor

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