Article reply “Godot is not the new Unity” from Juan Linietsky (BDFL of Godot)

https://gist.github.com/reduz/cb05fe96079e46785f08a79ec3b0ef21

by mdtrooper • 3 years ago

277 80 3 years ago

gist.github.com

mdtrooper• 3 years ago

The original link in HN is in: https://news.ycombinator.com/item?id=37561762

ladberg• 3 years ago

Additionally, modern processors all have at minimum 64 bit buses, so exposing anything other than 64 bit scalar types makes no sense.

I feel like this entirely disregards the caching costs of using >2x more memory in some cases, speed of float32 vs float64 operations on CPU, and potential CPU <-> GPU memory transfers.

EDIT: Nvm disregard this comment, I just noticed the existence of: PackedByteArray, PackedInt32Array, PackedInt64Array, PackedFloatArray, PackedDoubleArray

Anything set of numbers needed by the GPU or big enough to affect the cache will probably use those arrays.

jackmott42• 3 years ago

In the context of function parameters at the edge of C# and c++ I don't think it will ever amount to a large amount of memory being wasted. The cache point may be relevant, but generally if you are calling into C++ in tight loops from your scripting language in a game you have already screwed up. So maybe not so bad.

jayd162• 3 years ago

but generally if you are calling into C++ in tight loops from your scripting language in a game you have already screwed up.

How do you figure? Are you saying there should be no tight loops that hit engine code, none that live in the C#/scripting lifecycle or all tight loops should be rewritten in C++?

The elephant in the room, Unity, cross compiles the C# to C++ which makes this blanket statement about all games even more confusing to me.

lainga• 3 years ago

I think part of the problem is that using GDExtension is like a two-way FFI. You can call (C++) extension functions from GDScript, but the same interface and overhead are used to call (lib) Godot functions from the (C++) extension. AFAIK it's not like there's a <godot_impl.h> with engine functions that the compiler could inline.

Here's a good example (look, there I am!), although it's a bit old and actually led to perf improvement:

https://github.com/godotengine/godot-cpp/issues/1063

gabereiser• 3 years ago

Yes, however, by the time they fix the dictionary hack glue code as described, PCI bus transfer speeds will have increased (again).

I’m a fan of making everything 64bit from an api level, but sometimes you have to work with the right type for the architecture.

3seashells2• 3 years ago

Yet

jmull• 3 years ago

Strong response.

I'm not sure I would have been so generous to the author of the article this is in reply to. But I suppose that's a skill of a successful open source leader -- to turn interactions with critics into productive discussions rather than arguments, and perhaps even turn the critics into supporters.

It seems to have been that author who chose the FUD-ful title "Godot is not the new Unity". I guess there are times in life where you face a choice: be fair, reasonable, and intelligent, or... just try to get them clicks.

Well, that article got a lot of click. Good job?

kbelder• 3 years ago

I said this not long ago in a different thread, but after reading this article I want to say it again. I'm very impressed with the management of the Godot project. They seem to be avoiding all the common mistakes and drama that so many projects fall prey to. They're doing everything professionally.

Lerc• 3 years ago

I have contributed a very small amount of code to Godot. In the process of doing so I was very impressed with the entire process. They were very supportive and quick to respond. Overall it was one of the best open-source contribution interactions I have experienced.

JD557• 3 years ago

I'm not sure I would have been so generous to the author of the article this is in reply to. But I suppose that's a skill of a successful open source leader -- to turn interactions with critics into productive discussions rather than arguments, and perhaps even turn the critics into supporters.

FWIW, reduz (Godot author) and sprudd ("Godot is not the new Unity" author) previously discussed this on Reddit[1], and sprudd was actually sounded pretty nice (the first reply even includes a "and I hope that I wasn't too rude in the article. :)").

Overall, I think the original article was written in good faith, just with a click-baity title (and I imagine reduz thought the same thing). That might have helped to avoid a more angry reply.

1: https://www.reddit.com/r/godot/comments/16lti15/godot_is_not...

Xeamek• 3 years ago

Common now, the original article is perfectly reasonable one, and that includes its title as well.

For the past few days everyone is talking about Unity, and I don't think it's exaggeration to say that Godot has become the de facto alternative in low to mid level game development.

Godot itself will (if not already is) benefit from that status a lot. Article that brings highlights parts well Godot is lacking compared to Unity is perfectly valid criticism to have.

pelasaco2• 3 years ago

Godot itself will (if not already is) benefit from that status a lot. Article that brings highlights parts well Godot is lacking compared to Unity is perfectly valid criticism to have.

And that's because the author didn't even touch the "in-app" purchase and "in-app" ads capabilites from Godot x Unity, which is the way the studios complaining about the new Unity pricing, generate their income..

Rapzid2• 3 years ago

Agree 100%. The conversations sparked from this article are how the project improves. The maintainers seem very appreciative of it.

davidgerard• 3 years ago

The original author is also diving in to help with the problem he saw, which is an ideal outcome for a bug report from a new user.

json2d• 3 years ago

"Godot is/is not the new Unity" is a pretty loaded statement, and would mean different things to different folks.

This particular discussion focuses on the performance gap between the two engines looking specifically at how raycasts are implemented, and the larger implications from that analysis.

LarsDu885• 3 years ago

Somehow, I feel like reading that article diminished the original critique, however, inefficient raycasts aren't some sort of pathological edge case.

Raycasts are the most commonly used spatial queries in a 3d game. Hopefully this discussion will lead towards this issue being resolved.

I actually found Sam Pruden's complaint a bit odd since it sounds like he's developing a 2d game. If you're spamming 1000s of raycasts per frame for your 2d game, there's probably something else going on...

hutzlibu11• 3 years ago

"If you're spamming 1000s of raycasts per frame for your 2d game, there's probably something else going on..."

Yup .. but maybe not stupidity, but rather a non generic game.

In my case I need lots of raycasts, to determine what exactly the player and the enemy bots can see. Basically I have a simulation in 2D (using box2d directly in js as a wasm libary) - and all the bots and the player only (mostly) get information based on raycasts. They have to scan the world and react to that information, which leads to a different result, than the usual approach (cheating). So I am looking forward to get this fixed asap as well and also cannot really consider godot before that.

Edit: performance problems with raycasts I had to experience as well, because the roundtrip js to wasm is expensive. I first wrote a WebGPU shader doing only raycasting in my world, but better was modifying box2d (and compiling to wasm) to include a function, that does all my raycasts in one call and returns a big array (or rather a array with pointers to the structs in the internal wasm heap).

rngname22• 3 years ago

If the game is 2D and you can divide space into tiles/blocks and walls/obstacles have their own blocks/tiles (or you can easily establish a grid over your world and determine what cell each actor is in), I wonder if there's way to use BFS in a maze-solving manner to calculate shortest path between a given actor and the target you want to check visibility for, and if the distance in blocks/tiles returned by BFS/pseudo-pathfinding is greater than a direct distance formula calculation between the two blocks/cells then maybe you know there's an obstacle? I guess that requires you to be able to create the network/graph of traversable nodes as well.

ehutch792• 3 years ago

Wait. that doesn't sound like you're doing 1000s of raycasts? Just a few, maybe a dozen?

also, sounds like you're using JS, not Godot?

fidotron2• 3 years ago

because the roundtrip js to wasm is expensive.

Is this a thing?

I've been using ammo (wasm bullet) and while wasm interfacing certainly has a mismatch with idiomatic js I haven't knowably hit a problem with that bridge.

LarsDu885• 3 years ago

It's hard to tell without seeing a screenshot or video of the game in question, but there are almost certainly ways to optimize this problem.

If there are on the order of even several dozen enemies on the screen at any given time, you could simply maintain runtime sets of different factions and only do line-of-sight checks between hostile groups within a certain proximity.

There's probably hundreds of better ways to do this than by spamming raycasts. I have a VR space game with dozens of spaceships, and there are generally never more than num_spaceships raycasts getting fired every frame

db48x5• 3 years ago

If you’re doing thousands of raycasts per frame in any game, 2D or 3D, then something has gone wrong. Raycasts are very general, and there is often a more specialized way to get the same information that won’t require as much work.

moffkalast• 3 years ago

Maybe there's thousands of guns being fired.

pelasaco2• 3 years ago

I don't think how it can be wrong. I wrote a beaten-up game, 2.5D. Player(s) + Enemies + NPCs + Weapons + Bullets.. I can imagine that in some moments, we were easily doing a few hundreds of raycasts per frame.

bluescrn2• 3 years ago

I learned to code in the 8-bit days where you'd count to 1000 in a BASIC for loop to create a significant delay. I guess I've not got out of the mindset that doing anything 1000x is quite a lot (particularly when you're aiming to do it 60 or more times per second).

But as somebody working in Unity (and often on mobile), there's still many cases where 1000 of something is a lot, and should perhaps be cause to rethink your approach. For example 1000 draw calls, 1000 UI elements, 1000 instances of even the most simple prefab.

1000 raycasts per frame is also something that I'd try to avoid. But if they seemed important, you've just got to try it and profile it. Nobody can answer 'what is the cost of 1000 raycasts?' without a fair bit more information.

TazeTSchnitzel• 3 years ago

There are multiple APIs for doing raycasts in Godot; this one happens to be the least efficient.

Kiro• 3 years ago

Isn't that how you do line-of-sight/shadows, with thousands of raycasts for all pixels on screen?

kaibee• 3 years ago

Absolutely not. There's uh, a lot of tutorials on YouTube about how to go about implementing this kinda thing, depending on the kind of game (top-down 2d, vs 3d etc). Sorry don't have time to do a full write up lol.

starkparker• 3 years ago

That's raytracing. You can do LOS by raycasting only at line segments and points of blocking shapes, especially in 2D, which is the original post's concern. https://ncase.me/sight-and-light/

TylerGlaiel• 3 years ago

There's nothing wrong with spamming 1000s of raycasts per frame in a 2D game. They should be very cheap, so the performance impact of that should not be something you have to think about, and if some interaction or mechanic is easy to express with a boatload of raycasts, you should be able to just do that

LarsDu885• 3 years ago

It depends on the type of game, but 360 raycasts per bot is definitely a code smell that warrants a closer look at how the game is being architected.

Cyphus• 3 years ago

inefficient raycasts aren't some sort of pathological edge case.

You're right that raycasts aren't an edge case in terms of usage, but Juan Linietsky's point is that the inefficient path used for this API call is a rare exception to the efficient paths used by the vast majority of the API.

marcodiego• 3 years ago

Of course not. It won't have a draconian license agreement.

26fingies• 3 years ago

It seems weird to extrapolate where Godot will live in the game development ecosystem from its current performance characteristics for certain operations. It's like trying out Windows 95 and saying "Microsoft isn't going to dominate the PC world because Windows 95 crashes a lot!" Maybe.. but these sorts of technical minutae are not the things that determine winners as far as I can tell.

dundarious• 3 years ago

“Godot is not the new Unity” is a present tense statement, issued at a time when many studios are considering a hasty and impromptu transition from Unity -- they are looking for a suitable equivalent now, not many years into the future. It's a sensible question about today and the very near future.

gsuuon• 3 years ago

It sounds like Godot just needs a few more hands on deck to close up a lot of these smaller gaps, as Juan mentions most of the issues are already being discussed or were simply lower priority to fix. Hopefully with the influx of Unity refugees (and potential contributors) they'll be able to quicker ship more of the things they already have on their roadmap.

I do think the original article's claim of 'Godot is not the new Unity' is accurate, just not for the architectural reasons claimed. Folks probably shouldn't go into it thinking that Godot will handle every use case just as well as Unity. It hasn't had billions poured into it like Unity, but it is mature and ready for serious games. Plus - open source means you can just get your hands dirty and fix critical (for you) bugs instead of hoping Unity gets around to it.

philipov• 3 years ago

Offtopic: BDFL is a funny initialism. Although it means Benevolent Dictator For Life, its visual similarity to BOFH evokes a second meaning.

lukebitts• 3 years ago

Great response, I downloaded Godot because I was looking for a lightweight engine that doesn't take two minutes to load. This seems to explain the reason for the performance, I'm glad its one of their focus

stephc_int13• 3 years ago

I think this type of discussion can help the design team behind Godot to improve their practices and implementation, in the end it would be very healthy for the gamedev community to have a reliable and performance open-source engine as the "standard" for students, indies and AA projects alike.

Godot is better than Unity on many sides, but the internal architecture is coming from a place where they relied too much on naive and inefficient OOP constructs, those can be very hard to optimize later.

Performance should not be treated as a second class citizen when creating an engine, there are always solutions but it can be very time consuming to find workarounds to palliate design issues with the engine, it can also be a real motivation killer for a small team when they discover the framerate of their game on older/smaller devices...

kaveh808• 3 years ago

The killer feature of whatever game engine replaces Unity in developers' hearts and minds is going to be the platform delivery aspect.

Once you can press a button and get Win/Mac/Linux/Android/iOS/etc versions of your game built, you're in business.

All the higher-level features (3D, ray casting, etc) will be contributed by the community over time.

andrewmcwatters• 3 years ago

I think you mean lower-level.

johnnyanmac2• 3 years ago

Additionally, modern processors all have at minimum 64 bit buses, so exposing anything other than 64 bit scalar types makes no sense.

I believe the issue was less with the sizes of items being passed in and more with the API conforming to work with GDScript first and formost. Returning a dictionary for an operation that has a few float64's feels overkill and doesn't make sense even with an explanation of the available datatypes.

Only a pathological use case is shown, the rest of the API is fine.

I wouldn't call raycasting in a full blown engine "pathological". Especially one that touts 3D

Secondly, that doesn't inspire confidence. "Don't mind the room on fire, the rest of the house is fine!". The onus is on the engine to prove that, and numbers prevail over words. So far only one part of the conversation has shown that.

Even in the next sentence it sounds like they focus on a simple API over performance, and that doesn't fill me with confidence. If Godot isn't focusing on 3D, that is fine but there's so much noise trying to to say otherwise

Eventually, C# will be moved to the universal extension system and this will allow the unifying of the default and .net editors, it is just not the case yet, but its top in the list of priorities

I hope so, but there seems to be a trend of various "top priorities" from Godot that have trouble crossing the finish line. That's a reocurring issue even in this response alone: I'm not convinced that performance is a top priority for Godot. And that confidence means everything if the "BDFL" controls what gets into the project proper.

The problem is that, at the C++ level, this function takes a struct pointer for performance. But at the language binding API this is difficult to expose properly. This is very old code (dating to the opensourcing of Godot) and a Dictionary was hacked-in to use temporarily until something better is found

Yup... so 10 years later that hack stays in and modern programmers come cross it.

This isn't even a critique, that's simply the nature of legacy code. Unreal has an entire part of a forced namimg scheme (the compiler won't let you run the game without conforming) that can only be explained as "well we wanted to do this in the 90's but we slowly took it out sp it's not relevant today". But if it took 10 years for someone to do more than a few dozen raycasts a frame, it says more about the battletesting than any deep dive. It goes back to my confidence above.

, you need to create a C# version of a C++ instance as an adapter... Why is it troublesome? because C# has a garbage collector and C++ does not.

slight nitpick: while garbage collection is annoying, you technically do have a built in way to disable it in certain regions, as well as the option in later versions to have unmanaged blocks of code. I'm not saying this is easy to do, but it is something that developers much smarter than me in c# have gotten around. I know c# bindings was a relatively recent endeavor so I'm not going to give it too much flak

Godot containers don't work like STL containers. Because they are used mainly to pass data around, they are allocated once and then kept via reference counting.

1) reference counting implies some sort of automated memory free-ing scheme. 2) That doesn't necessarily address potential issues of inefficiently allocating memory and keeping it contiguous. But I won't talk much on that because I'd need to first read more on the engine's memory allocating schemes first.

Godot uses far more optimized containers that are not directly exposed to the binder API.

Okay, but why? Someone wanting to use C# or c++ or whatever script extension that isn't GDScript wants those optimized containers. Does it go back to the earlier quote of "it's difficult to get right and no one wanted it"?

As a result, we created a special path for GDScript to call more efficiently.

okay, and the link is... an open issue on Github made 2 months ago, with no additional comments or discussions. Simply a request from a code owner.

I don't know if this conversation is simply happening in IRC/chat, but it's unusual given how much other activity I have seen in other PR's/proposals (recent and from years prior). Was this the best reassurance that they are addressing performance?

---------

I don't mean to sound like a downer, but I feel the article is overall missing the forest for the trees. I've read about several different kinds of devs from years prior talk about how they passed on Godot because they hit hitch after hitch once they were doing something slightly advanced. a dismissal of "this is a pathological use case" sounds fine in a vacuum, but it sounds like this has been a long standing issue, and priorities simply weren't on smoothing out such hitches.

I'm not saying they should have listened to those devs, but I think the most frustrating thing is that I don't know what or who Godot wants to service. So far it sounds like they want to have all the cake, but currently are also low-key fine being a hobbyist 2D engine that can maybe do some simple 3D stuff. Which again, is fine. But that's not what it sounds like Godot is selling. It unfortunately reminds me a lot of Unity, both on the outside (yeah, having 2 unsupported netcode solutions with a 3rd in pre-alpha isn't a good look) and within the company itself. I'll quote some part of a post from the creator of Rimworld, who had similar evaluation and conclusions over 5 years ago:

There's obviously a tremendous amount of technical talent going into Godot, but from what I can tell there's no strategic thought about market positioning or success pathways or goal pillars at all. It basically comes down to "make a good game engine", with all the lack of boundaries and lack of focus that implies.
My initial thought: Be best at one valuable thing first, then expand out from there into adjacent domains, using the momentum accrued from the initial success. (e.g. If you want to build a restaurant empire, you start with one restaurant to dominate one neighborhood and then expand from there - you don't try to build 100 restaurants at once).

imtringued• 3 years ago

Additionally, modern processors all have at minimum 64 bit buses, so exposing anything other than 64 bit scalar types makes no sense.

Yeah but you have a 32 bit data type and a packed 32 bit array, so why not have the same for 16 bit? Not just that, there are also SIMD operations that work better with 16 bit numbers.

throwawayyy9237• 3 years ago

"Godot is not production ready"

Personally, I find this a refreshing admission.

Article reply “Godot is not the new Unity” from Juan Linietsky (BDFL of Godot)

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