I wouldn't say ECS is unstable or buggy
#archived-dots
safe lintel
incomplete is how i would phrase it. ymmv depending on your ability to overcome whats missing
safe lintel
i cant answer that
median glen
No one can lmao
safe lintel
simple questions of when its ready you should bring to them on the forums
sand prawn
I found NetCode didn't suit my purposes, but DOTSNET was good enough (and quite performant on the server side)
tired mulch
I'm also having some thoughts about if I should use NetCode or not, or if I might go with a different approach.
I'm currently writing a 2d shooter game with ECS, where I create pretty much everything from code (custom renderer etc).
NetCode as I've seen does everything with prefabs when it comes to creating players / objects that should be predictable (Ghosts) etc.
Is there some form of workflow where I won't need to create prefabs for everything, because that doesn't really fit the creation of a 2d game using spritesheets with a custom renderer etc.
I thought about possibly using Unity Transport to create my own custom solution and maybe borrow some concepts from NetCode.
Any advice would be appreciated!
stoic monolith
Ok just wanna confirm.
U can NOT interact with unity default physics (physx) from Jobs, right?
stoic monolith
What are ParallelForBatch for?
I wanna update all my PS particles in a single big nativearray for locality, is this possible? Like, give array of particleSystem as input for the job?
zenith wyvern
If you mean IJobParallelForBatch it lets you a define a batch size, so the scheduler will spawn one job for each batch size until it hits length
So you could have a bunch of jobs running over N different elements of a single container
stoic monolith
But the ParallelFor also got a "minIndicesPerJobCount", what's the difference?
Oh wait, so parallelFor actually executes per index, while batch executes a range of index
zenith wyvern
Exactly
stoic monolith
Ok im still trying out the different jobs
But really, my case is, i got on average 100 PS at a time, just 30 particles each
If each PS schedules its own job, im kinda suspecting it's not very efficient?
That's why i'm looking into how to combine all the particles from all the (registered) PS to be handled in a bigger "batch".
Bcoz well, in my case the max batch size for each of the PS will only be 30 and that's kinda small i guess?
Like, this doesnt look very efficient?
zenith wyvern
I would say it would be better if you could combine a bunch of your particle systems and feed them into fewer jobs, yeah. No idea how you would do that though, sorry
stoic monolith
Yeah i did this in the past. At least in the actual game, the same "Skill" just asks the particle manager to spawn x amount normall (to make use of the spawn parameters) then offset by the pos/rot requested
Anyways hmm, yeah i'll have to think about this a bit
Oh wait just another confirmation
So the difference between the ParallelFor and the Batch, in terms of use case, is i guess..
ParallelFor works on each index. So i assume this is better for a "heavier" element in the array
Whereas the Batch is more for the "smaller" element arrays, a single Execute can zip through a bunch at once so its better for bigger element arrays
zenith wyvern
Yes, parallelfor is for when you need to do a lot of work per index. ParallelForBatch is for when you need to do less work but have a lot of indices to go through
You wouldn't want to use ParallelFor for very large arrays since you'd be creating a lot of overhead from all the job scheduling
stoic monolith
In the context of particles, then i'd say i'd have to really do some weird stuff on single particles to really make use of the ParallelFor, i guess?
zenith wyvern
I would think doing everything in a single job would be fine, especially with burst
Don't underestimate how fast it can tear through linear arrays
Even huge ones
stoic monolith
Im testing gradually to 1 job for 3000 elements
Yes it reaches 200fps eventually(the highest out of all the numbers), but always starts slow on the fps. Like it needs to warm up
zenith wyvern
I've heard burst jobs won't compile for the first couple of runs. So it will run slow a couple of times then go insanely fast
That's been my observation with my pathfinding library
stoic monolith
2job x 1500array, gets to 200fps in like 20secs
1job x 3000array, wow really slow. 5fps for 30secs, 100fps in 1 min, and now like 1.30 mins finally gets to 200
gentle osprey
Hey, is there any constraints I could put on my generics that would make this possible? I have some places where I need to convert stuff from UInt16 to Int32, etc, and would like to avoid having to type out all the permutations
public struct ConvertJob<T, U> : IJob
where T : struct
where U : struct
{
[ReadOnly]
public NativeArray<T> Src;
[WriteOnly]
public NativeArray<U> Dst;
public void Execute()
{
for (int i = 0; i < Src.Length; i++)
Dst[i] = (U)Src[i];
}
}
Like, some where T : Castable<U> or something.
zenith wyvern
Are you sure you're running with burst on and safety checks disabled?
stoic monolith
But my profiler still looks like this
(Yes i'm dealing with unity physx so that must be the big overhead)
zenith wyvern
Hahah...yeah it certainly looks like physx is your bottleneck there
I don't think there's a way to add castability to generic constraints
C# generics are pretty limited
gentle osprey
I see, shame. Thanks anyway :)
zenith wyvern
@gentle osprey UnsafeUtility.MemCpy(Src.GetUnsafePtr(), Dst.GetUnsafePtr(), Dst.Length); You could try something like that...I'm assuming that wouldn't end well
But maybe something along those lines
gentle osprey
That would break due to different memory representations no?
gentle osprey
Would break for the same reason as MemCpy.
I Could perhaps do MemCpyStride. https://docs.unity3d.com/2019.4/Documentation/ScriptReference/Unity.Collections.LowLevel.Unsafe.UnsafeUtility.MemCpyStride.html
zenith wyvern
Oh yeah that seems potentially promising
gentle osprey
Though, I don't get what the documentation is trying to say, because incrementing the destination with both destination and source stride makes no sense to me.
https://forum.unity.com/threads/unsafeutility-memcpystride-just-seems-broken.542734/ Looks like I'm not the only one :P
zenith wyvern
Yeah I'm staring at it trying to make sense of it. No idea
stoic monolith
Can i have a continuously running Job, without the the main thread ever needing any nativearray access (or not even use any nativearray at all)
So i dont have to schedule every frame whatsoever. Only once, or "once in a while" ?
dusty sleet
Hi guys, I found that if I don't restrict local native array as readonly, I can't access its elements other than the the same id as entityInQueryIndex one. Why is that?
stiff skiff
Likely because it doesnt know if you're reading or writing there
It just checks if the index is outside of it's allowed range
which is fine when reading, but could cause race conditions when writing
dusty sleet
so if I do want to write, I can't write to other index of that container?
stiff skiff
Pass in a copy of the same array
To give a clearer example of the issue here. Lets say your array had 4 values. index 0 1 2 3.
Lets say this is split over 2 jobs
then job 0 will be reading from 0, then write to 0. Then read from 1 AND 0, and write to 1
job 1 will read from 2 AND 1, then write to 2, then read from 3 AND 2, then write to 3
Notice how job 1 is reading from 1, while job 0 is writing to this
if this happens at the same time, you have a race condition and stuff breaks
dusty sleet
oh I understand, so the read and the write happens on two arrays. so no problem
odd cipher
In ECS, is using 'in' instead of 'ref' any faster?
deft stump
yes.
the burst compiler can expect to just read the data.
karmic basin
In is readonly, ref is to update. Si yeah prefer in if you only need to read a var
amber flicker
always want to use in where you can - if you test it in isolation it might not appear much/any faster but it makes a massive difference at scale due to the scheduling
odd cipher
Alright nice
stoic monolith
I have Mathematics installed but can't do using the namespace?
amber flicker
are you using asmdefs? Have you added a reference to the package if so?
stoic monolith
Ah that's probly it
Sorry another question (since dots people deal with package headaches often)
How do i uninstall package, if it's not showing in the package manager?
This is Newtonsoft json, apparently it's conflicting bcoz i have 2 of them?
amber flicker
if it's not showing in the package manager you may just need to enable 'show dependencies' in the project settings but the easiest way is just to edit the manifest file directly
which is in the `Project/Packages' folder
amber flicker
hmm haven't seen that, are you using some 3rd party thing with a version in? If you haven't tried it yet, it's always worth trying a complete rebuild of your library.
odd cipher
I'm trying to make a quick utility to make it easier to instantiate entities from prefabs but it for some reason gives an error saying that the 'settings' variable is null. I'm not sure why it's null. ```csharp
static EntityManager entityManager;
static BlobAssetStore blobAssetStore;
static GameObjectConversionSettings settings;
static Dictionary<GameObject, Entity> prefabsAsEntities;
static bool initialized = false;
public static Entity Instantiate(GameObject prefab) {
if (!initialized) {
World defaultWorld = World.DefaultGameObjectInjectionWorld;
entityManager = defaultWorld.EntityManager;
blobAssetStore = new BlobAssetStore();
settings = GameObjectConversionSettings.FromWorld(defaultWorld, blobAssetStore);
Debug.Log("A");
}
if (!prefabsAsEntities.ContainsKey(prefab)) prefabsAsEntities.Add(prefab, GameObjectConversionUtility.ConvertGameObjectHierarchy(prefab, settings));
return entityManager.Instantiate(prefabsAsEntities[prefab]);
}
would recommend you avoid statics - my guess is you will almost certainly run into problems trying to e.g. store a static of the BlobAssetStore like that
odd cipher
I suppose that makes sense, I'll make it into a GameObject instead and see if that works.
amber flicker
hmm static methods are fine but I'd suggest e.g. passing in the EntityManager as a parameter
actually, I'm not sure you want to be creating a new blob asset store like that
odd cipher
It's how I've done it before and it worked so I'm not sure why it wouldn't work now
but as I mentioned the error is that the settings variable is null even though that line that sets it gets executed.
amber flicker
try passing in null instead of blobAssetStore
Entity entity = GameObjectConversionUtility.ConvertGameObjectHierarchy(gameObject, GameObjectConversionSettings.FromWorld( World.DefaultGameObjectInjectionWorld, null));
``` works for meNope, same error.
amber flicker
paste the error - also when are you calling this?
odd cipher
You can see all of that info here
amber flicker
according to what you pasted line 18 is saying nullrefexception for prefabsAsEntities[prefab]
odd cipher
Ah yikes, I thought it was referencing the settings but the problem was that I never created the dictionary
well, that's embarrassing
stoic monolith
Hi guys
So i'm doing some IJobParticleSystem, and the docs suggests to call this in OnParticleUpdateJobScheduled bcoz that's when the default PS simulation would already be scheduled.
Is it possible to simulate fast forward the default job inside ur job?
So if normally i schedule a "move particle towards a pos" job per frame. I wanna do 5 seconds worth of this (5 x framepersecond) taking into account the default PS simulation
Possible?
odd cipher
So for context, I need to be able to find the closest entity with a certain component from another entity. And there are thousands of those entities. I'm not sure what a good way would be to go about this without causing lag problems. I suppose something like a quadtree could work but I do not know how that would work in DOTS. I do use the Physics package so that might have something, dunno.
olive kite
Is anyone else experiencing emission not working after converting to entity?
deft stump
So for context, I need to be able to find the closest entity with a certain comp...
You could query first a singleton entity, getting its translation
Then do an entity foreach (in translation, in componentX) and then compare if they're close or not.
odd cipher
Do you think you could explain the 'query first a singleton entity' a bit further? I'm not sure I understand
karmic basin
I think he meant "single" entity ?
Try YouTube Channel of Code Monkey, he has a good spatial search tuto with quadtree
odd cipher
Oh! I didn't know he had a video on that, I saw the original Find Target video which wasn't very efficient in my case, Hopefully this will be much better.
Thank you for mentioning it
karmic basin
You're welcome. Happy coding.
stoic monolith
How do i debug this?
I have LeakDetection Full Stack Trace and there's no difference
deft stump
do you have any Native Containers that are set as TempJob?
check if any of those aren't being disposed
stoic monolith
Yeah it was an error elsewhere.. 😄
stoic monolith
Sorry not so dots related
Why is this wrong?
amber flicker
@stoic monolith because you're comparing 3 elements - you can use e.g. math.all(tr == float3.zero)
stoic monolith
Is that the same as this btw?
tr.Equals(float3.zero)
amber flicker
that's also good yup 👍
stoic monolith
Ive been using Allocator.Persistent most of the time
So i have a single PS for a shot skill, it can last anywhere between 1sec to 20sec
I have nativearray<byte> to store the state of each particle, bcoz it's relevant for the whole lifetime
Then i also have array for positions of all particles. It used to be TempJob but now i'm changing it to Persistent too
Is this... appropriate?
maiden delta
how do i use MotionVelocity to apply forces to rigidbodies in unity/havok physics?
i was told to use it instead of ApplyAngularImpulse in PhysicsWorld
but when i try to get it as component data i get an error that it's not component data parameter 'velocityMotion' has type MotionVelocity. This type is not a IComponentData / ISharedComponentData and is therefore not a supported parameter type for Entities.ForEach.
and if it's not component data, how do i use it?
hollow sorrel
@maiden delta the component is called PhysicsVelocity i think
compact robin
Hey, is there anyway to do Physics.Simulate() in DOTS?
scarlet inlet
@compact robin probably more than one
what we do is to create a world dedicated for the physic and then do world.update
ofc this may not work in your case
compact robin
What does world.update do?
scarlet inlet
it updates all the systems in the world, which for us are basically only the physic systems
it ticks them
compact robin
Like it calls Update()?
scarlet inlet
yes
compact robin
Oh how do you disable it?
scarlet inlet
you must disable the auto system creation and add the system manually in the world
when you do that, you just don't put it in the update system
if you don't know what I am talking about , I will show you some code
compact robin
Yes pls lol I'm new to DOTS
scarlet inlet
var physicsWorld = new World("Default");
World.DefaultGameObjectInjectionWorld = physicsWorld;
physicsWorld.AddSystem(new YourSystem());
it is actually straightforward how the systems are managed inside the world
if you want to get the standard systems, including the physic ones you do:
world = new World("Svelto<>UECS world");
var systems = DefaultWorldInitialization.GetAllSystems(WorldSystemFilterFlags.Default);
DefaultWorldInitialization.AddSystemsToRootLevelSystemGroups(world, systems);
World.DefaultGameObjectInjectionWorld = world;
tbh unless I would do something very simple, I prefer to use the manual way
much more control
compact robin
Oh
Ok so the first one is adding your own system, while the latter is like the default?
scarlet inlet
the latter adds to my custom world all the default systems
then I can add mine too
compact robin
Meaning it calls update() on its own?
scarlet inlet
you know what? I am actually not sure what calls Update() automatically since I have never used it 🙂
but nope, when you do it manually, it's not called
compact robin
Oh
Do I have to run World.DefaultGameObjectInjectionWorld = physicsWorld;
If I just wanna create a secondary world to simulate physics
scarlet inlet
no that's only for when you want to use the world from inside monobehaviours that is not a great thing to do anyway
you can have only one default world
compact robin
Isn't DefaultGameObjectInjectionWorld the world GOs are injected into during the start of the game?
scarlet inlet
check the multiple world part: https://docs.unity3d.com/Packages/com.unity.entities@0.1/manual/system_update_order.html
as far as I understood is a naive way to access to a world from inside a monobehaviour
I don't think it's used for GO to entity conversion, but I may be wrong
it shouldn't be used IMO
scarlet inlet
at that point you do physicsWorld.Update()
which is what we do as we want complete control over the ticking
scarlet inlet
I don't blame you, as the automatic system hides too much logic
compact robin
Like I wanna step forward by 0.25f
scarlet inlet
but in reality is quite simple
compact robin
Every call
compact robin
Physics.Simulate(Time.fixedDeltaTime);
Which is 0.25 I think
By default
Like an ECS version of this
scarlet inlet
var currentElapsedTime = Time.ElapsedTime;
World.SetTime(new TimeData(currentElapsedTime, UnityEngine.Time.fixedDeltaTime));
that's what we do
you can override the time used inside the systems
scarlet inlet
you have control on what you want to do
yes
you don't need to use fixedDeltaTime
we do only because we read the value from the editor settings
scarlet inlet
yes there are reason why it can get hard of course
scarlet inlet
this in fact is not about ECS
compact robin
Yeah
scarlet inlet
it's confusing because with the auto ticking/creation you don't know exactly what is going on
but studying it is useful
compact robin
Ok so just to reemphasize
var physicsWorld = new World("Default");
World.DefaultGameObjectInjectionWorld = physicsWorld;
physicsWorld.AddSystem(new YourSystem());
This wouldn't auto-tick right
world = new World("Svelto<>UECS world");
var systems = DefaultWorldInitialization.GetAllSystems(WorldSystemFilterFlags.Default);
DefaultWorldInitialization.AddSystemsToRootLevelSystemGroups(world, systems);
World.DefaultGameObjectInjectionWorld = world;
But this will
distant imp
Let's say I want to have 1000 quads in different colors, my code would look like this:
for (var i = 0; i < 1000; i++)
{
var entity = EntityManager.CreateEntity(quadArchetype);
var mesh = CreateRandomSizeMesh();
var material = CreateRandomColorMaterial();
EntityManager.AddSharedComponentData(new RenderMesh { mesh = mesh, material = material });
}
As far as I know SharedComponent makes the entity unique if the value is different making it take a chunk for itself. With the code above, I end up with 1000 chunks with only 1 entity in it (assuming all quads will have different size and color). Is there any way to optimise such case?
hollow sorrel
@distant imp you def don't want to create 1000 different materials for that case
if you're using hybrid renderer look into material overrides
it should have an example scene but not sure
for the meshes you could reuse the same quad mesh and scale them differently if you want random sizes so you only need 1 rendermesh sharedcomponent
distant imp
@hollow sorrel I've been trying to find info about material overrides, but they only seem to be available using custom shader graph. However we write our own custom shaders and create our materials in the code, and I can't find any info on how to do it in code.
Good tip on using scale on quad sizes though, thanks!
hollow sorrel
yea you can use them in code too
having a hard time finding docs on it atm but from what i remember you just add the component you want to override to your entity and it should just work
i think BaseColor is the one for color
gotta set its value too
for custom materials/shaders there is also a way to create new override components in code
not sure if this one is still accurate or outdated but https://forum.unity.com/threads/per-instance-material-params-support-in-entities-0-2.782207/
distant imp
Thanks! I read through the thread, and it seems I have to create a shader graph and a material in the Editor. I will try and reverse engineer the generated shader and see what I can figure out from there. Thanks again!
dull copper
safe lintel
Maybe this is it 😀
pliant pike
stupid basic question but how do I get a specific entity from an entitymanager in a monobehaviour?
neh mind I think I got it CreateEntityQuery then ToEntityArray
odd cipher
Hello, I'm wondering how I could avoid the Structural Changes error on the main thread, I want to add something to a DynamicBuffer Element on the mainthread but that same Element gets altered in a System which runs every frame parallel. Which causes the mentioned error.
deft stump
look up EntityCommandBuffer
also
I see a struct called nativestring
is this a way to pass a string into a native container?
low tangle
yes, but use FixedString<number>
nativestring was the previous name, fixed string is the newer ones that can be appended and what not
deft stump
nice nice
compact robin
Hey guys, what's the FixedUpdate() equivalent of DOTS?
pulsar jay
Can anybody explain CollisionFilters to me? The docs only have an example colliding with all layers which isnt helpful. I dont really get why I need a BelongsTo for a raycast and setting both (BelongsTo and CollidesWith) does not change anything. It still returns every collider regardless of its layer:
{
BelongsTo = 1u << 1,
CollidesWith = 1u << 1,
GroupIndex = 0
};```As the first layer is called 0: (Undefined Physics Category) is it 0u or 1u << 1 in code?
pulsar jay
Ok found it: Layer 0 is actually 1u
And one has to be really specific on each object about what can collide with what
compact robin
Hey guys, what's the FixedUpdate() equivalent of DOTS?
Hey so I did some research and found FixedRateUtils
I wonder what's the diff between EnableFixedRateSimple(ComponentSystemGroup, Single) and EnableFixedRateWithCatchUp(ComponentSystemGroup, Single)
zenith wyvern
compact robin
Oh I see
I'm still confused as to why OnUpdate() is not called for Worlds I manually create @_@
lean raptor
What is the Unity Job equivalent of Physics.OverlapSphere?
karmic basin
With or without ECS ?
lean raptor
I don't use DOTS if you mean that, but the every day GameObjects
karmic basin
With ECS there's an example on the manual, I can show you the link.
Without, I'm not sure it's supported, you would have to do so in main thread but you probs want multithreading so you might need to make your own distance check
lean raptor
With ECS there's an example on the manual, I can show you the link.
Can you post the link please?
Maybe I found something useful that I can use outside ECS
rancid geode
@lean raptor have you tried SpherecastCommand? https://docs.unity3d.com/2018.3/Documentation/ScriptReference/SpherecastCommand.html
I am not sure if it works on already overlapping colliders, but you can try. If it works, using it with distance = 0 should be the equivalent to a OverlapSphere
gusty comet
Hello, I wonder how could I pass particle system to a entity?
lean raptor
Ok, I'll see
karmic basin
@lean raptor I was thinking of this one for ECS, look the collider example they use a sphere https://docs.unity3d.com/Packages/com.unity.physics@0.0/manual/collision_queries.html
Link posted by Bruno looks interesting too
stray yoke
i'm new in DOTS and i want to know where i can find resources to learn
compact robin
I wonder as well :c
karmic basin
CodeMonkey has a lot of Youtube videos on the topic
But first I recommend reading the official manual
Well not a lot of videos, but good ones on programming with ECS
compact robin
I'm trying to make multiple worlds in which I can simulate physics in, but I can't seem to find resources on that @_@
karmic basin
Alright try the Unity Official github
they have many physics with ECS axamples
And more specifically for physics https://github.com/Unity-Technologies/EntityComponentSystemSamples/blob/master/UnityPhysicsSamples/Documentation/samples.md
maybe they did multiple worlds simulations, otherwise the Physics package manual should give you a starting point I hope
compact robin
I don't think they did unfortunately :c
distant imp
I want to remove a component from an entity that is referenced by a component I'm iterating on, how do I go about it?
This doesn't seem to work:
var commandBuffer = _endSimEcbSystem.CreateCommandBuffer().AsParallelWriter();
Entities.ForEach((Entity entity,
int entityInQueryIndex,
in MyComponentWithEntity component) =>
{
commandBuffer.RemoveComponent<ComponentIWantRemoved>(entityInQueryIndex, component.Entity);
})
.ScheduleParallel();
Never mind, it seems to work now 🤔
pliant pike
don't suppose anyone knows the syntax for the nativearray contains method?
the docs don't seem to make any sense or make it clear it seems it's like this currentnativearray.Contains<Entity, 0>(0);
but that doesn't work
distant imp
It should just be currentnativearray.Contains(0); assuming your native array is NativeArray<int>
It's the same as saying currentnativearray<int, int>.Contains(0)
odd cipher
@karmic basin I'm having some trouble converting the Quadrant system from his video to the new way ECS works, There was a comment on the video with a Github link to a working version for how it works now but still not sure how to get that working either.
pliant pike
thanks, Jonah I guess the problem is the native array is of type nativearray<Entity>
karmic basin
<@!317274156578111488> I'm having some trouble converting the Quadrant system fr...
Yeah it was some time ago he was one of the first to publish videos on ECS and the specs changed a lot at that time
odd cipher
Mhm, it's making it quite a bit difficult for me to remake it.
pliant pike
not sure what I would use for that, I just need to figure out if the native array contains any entitys at all
karmic basin
Mhm, it's making it quite a bit difficult for me to remake it.
The concept is still a robust one to learn. What are you trying to achieve ? I don't remember
odd cipher
A quadtree to make it more efficient to find the nearest entity. But I'm not sure if it's a great solution.
karmic basin
not sure what I would use for that, I just need to figure out if the native arra...
yourNativeArray.Length > 0 ?
karmic basin
A quadtree to make it more efficient to find the nearest entity. But I'm not sur...
Yeah it is when you scale a lot.
odd cipher
True but it seems a bit difficult to implement for ECS
karmic basin
Easiest way is to have a double for loop and check distance between each object against each other object in the scene, keeping only the lowest one, but please dont do that if you have many objects 🙂
odd cipher
Yes that's the problem. It's what I am doing currently but it is way too slow for what I need.
karmic basin
ANother solution is, if you have a maximum range, to use a sphere around origin object position, and check if something inside. Using Physics so might not be more simple in the end :p
odd cipher
Yeah I am using Physics and I would like to have a maximum range so that might be the best solution? not sure.
karmic basin
Alright, I got a link for you to study, gimme a sec
CHeck the "Collider casts" example
sorry link was wrong
^^
odd cipher
Alright
karmic basin
they cast a sphere and check if any entity collide with it
odd cipher
Do you know how performant this is?
compact robin
<@!773209210904903680> Check out the pool example
Aight I will have a look thanks :>
distant imp
not sure what I would use for that, I just need to figure out if the native arra...
It depends on how you're creating/getting the native array. If you're creating it manually like so: myNativeArray = new NativeArray<Entity>(5, Allocator.Persistent); then doing a myNativeArray.Length > 0 will always return true. However you can use LINQ's Any extension method to check if there's any non-null entity in the native array, i.e.: myNativeArray.Any(e => e != Entity.Null)
pliant pike
awesome, thanks @distant imp
karmic basin
Oh right the length is preallocated, my bad
pliant pike
yeah, I should have said I did try length
karmic basin
Do you know how performant this is?
Depends on your scene. I'd say first try to ake it work, see if that's what you're looking for. If so, then convert it as a job so you can finally use Burst 🙂
odd cipher
Alright
compact robin
var World = new World("Test 5");
var CSG = World.GetOrCreateSystem<Test5SystemGroup>();
Can someone tell me why the system is not showing up in the Systems Debugger?
deft stump
when did they say that enable/disable components is going to be released?
opaque ledge
i think they mentioned that 2 months ago
deft stump
yeah iirc, it's going to be relased on december right?
opaque ledge
i dont think they gave any release date
opaque ledge
arent we in q4 2020 rn ? 😄
karmic basin
```cs
var World = new World("Test 5");
var CSG = World.GetOrCre...
Do you .Update() your system at some point ?
compact robin
Yes
Both .Update() and without Update() doesn't work
Apparently it only works if I add it to playerloop
But that's not what I want
Besides, that approach only works for 1 world @_@
karmic basin
ANd if you choose an arbitrary systemgroup and AddSystemToUpdateList() in that group ?
compact robin
Yes
var World = new World("Test 4");
var Systems = DefaultWorldInitialization.GetAllSystems(WorldSystemFilterFlags.Default);
DefaultWorldInitialization.AddSystemsToRootLevelSystemGroups(World, Systems);
World.EntityManager.MoveEntitiesFrom(World.DefaultGameObjectInjectionWorld.EntityManager);
var SysGrp = World.GetOrCreateSystem<SimulationSystemGroup>();
World.DestroySystem(World.GetExistingSystem<PresentationSystemGroup>());
World.DestroySystem(World.GetExistingSystem<InitializationSystemGroup>());
var Sys = World.GetOrCreateSystem<Test4System>();
SysGrp.AddSystemToUpdateList(Sys);
Btw do you think this is a good idea if I just need to like simulate physics
deft stump
arent we in q4 2020 rn ? 😄
Not in unity's calendar. to them it must still be q2 2020
compact robin
Ignore the MoveEntitiesFrom() btw, that's just to test if physics work
karmic basin
Nah I dont think so. Might be better to use Physics.Simulation like in the pool example
karmic basin
I know you can control the step of simulation at least in the future. You're saying it doesn't work in the past ?
backwards
compact robin
No like I wanna do some sort of client prediction
And it needs to rewind time and check if the prediction is accurate
Also some lag compensation server-side
compact robin
Something like that
And I don't think Physics.Simulate() or whatever it was called would work out
I want a custom physics world where I can update at a fixed rate
Or on demand
karmic basin
Did you check the official DOTS multiplayer FPS example ? they stopped support but implemented all that
compact robin
They use some ghost authoring comp which I don't quite understand tbh
I bet they use a separate world as well
karmic basin
I didnt dig that project that far so couldnt tell, looks like you studied it more than me
compact robin
Tbh no
I'm not certain
I'm really new to all this ECS stuff
Struggling cuz there's lack of documentation
Like what could be easily implemented in monobehaviour objects would take hours of research and / or asking here
karmic basin
Yeah it's still early and lot of boilerplate
compact robin
I mean it has been 2 years, no?
karmic basin
Probs... Time flies by so fast
compact robin
Oh yeah
My above code works so far, but I'm concerned as to whether
World.DestroySystem(World.GetExistingSystem<PresentationSystemGroup>());
World.DestroySystem(World.GetExistingSystem<InitializationSystemGroup>());
Would have any form of negative repercussions
Like I don't need any of the drawing
But idk what InitializationSystemGroup is for
karmic basin
Ok so the main idea it that your server is authoritative and compute the physics simulation in another world. And for lag compensation you can invalidate the simulation and make another one, right ?
Honestly I think it's overkill yeah
But I never implemented what you're trying, so...
compact robin
For lag compensation you have to rewind time
Because the client input is always behind due to latency
karmic basin
Yeah but you can do it in a standard way
compact robin
How? I don't get it
karmic basin
Weither you simulate another world or not
is not relevant I guess ? Unless you encountered a blocker
compact robin
Because I don't want to affect my present world
the present world still runs
I just want to rewind time when like say, a player shoots another player
And I think a separate world is the best way to do it
Or rather easiest
xd
karmic basin
I think I dont understand why you want to rewind time.
I would assume server is authoritative so whatever data it sends to the client, the client override its own, eventually interpolating so it doesnt teleport. And then prey for low ping :P
What am I missing in your project ?
compact robin
Because the client's requests are always behind time
Due to latency
Like say if the client has 100 ms round trip to server
The req would be 50 ms behind present server time
That might make shots inaccurate, so we need to rewind to 50 ms from before
And see if like say, a raycast actually hits
karmic basin
Ok that looks like a standard network concern. I don't think the whole simulating in another world is relevant
compact robin
But I also want to keep current simulation on-going while that happens
compact robin
Ok that looks like a standard network concern. I don't think the whole simulatin...
I was trying to do it in another world because it felt like the easiest way to do it
I also don't have to affect my current world
karmic basin
But current simulation is invalidated if you receive new input ?
Ok I fear I'm not sure I understand what you need, sorry
compact robin
But current simulation is invalidated if you receive new input ?
No it will always be behind time
Requests will always be behind server time
karmic basin
You want movement prediction on the cliet then ?
compact robin
So I need to rewind :c
north bay
A world just to do backwards reconciliation sound really overkill to me
north bay
Do you only need to rewind them to process the request? And what do those requests look like?
compact robin
Dots
north bay
Or a custom implementation?
compact robin
I plan to do it via dots
I want to like rewind time server-side, raycast and do stuff if it hits
karmic basin
You mean your simulation has to be deterministic based on frame number ?
north bay
Well then you are pretty good to go already.
The Netcode package has an assembly that is called Unity.Netcode.Physics which makes use of a class called PhysicsWorldHistory which stores the PhysicsWorld for the last x ticks.
compact robin
But what if I don't want to use the netcode package?
north bay
Than you grab that assembly from the package cache, copy it into your assets and uninstall the package
Modify the code of it so it takes your time logic
Should be fairly straight forward
karmic basin
Not always, but not suited to your network case
compact robin
Why?
north bay
Cause you would clone lots of none essential data
How would you set that up? You would have to sync between that physics world, your simulation world and your presentation?
compact robin
I mean its sole purpose is just to see if a shot hits
north bay
If that's all you want to do I highly recommend to check the PhysicsWorld of the Dots Physics package out, or the PhysicsWorldHistory of the netcode package
north bay
Yes, that's what the PhysicsWorldHistory does based upon ticks
compact robin
Wow interesting
north bay
The PhysicsWorld struct has a method called clone if i remember correctly
compact robin
:o
Yeah now my "solution" sounds overkill LOL
Not to sound dumb, but is it possible to step like a physicsworld forward by x amount of steps
If what I'm asking even makes sense xd
karmic basin
yes it is
karmic basin
you can .stepImmediate() or smthg like that, check API reference
karmic basin
yeah
compact robin
The problem is Unity docs don't really explain how to use them
:c
Though I do have a rough idea
I just hope it works xd
north bay
That's the nature of DOTS docs 😉
compact robin
Yeah the lack of documentation is why its hard to use
Sadly
I have a theory they are just doing this on purpose so braindead people like me don't spam their forums with stupid shit xd
Like they want people who actually know their stuff to use it
🧐
World.DestroySystem(World.GetExistingSystem<PresentationSystemGroup>());
World.DestroySystem(World.GetExistingSystem<InitializationSystemGroup>());
Back to my original question though, are there any repercussions as to doing this
Because even if I don't have an additional world to simulate physics, I still want a world whereby I can tick my own time
odd cipher
@karmic basin I'm having some trouble understand how to get CollisionFilters to work. They seem to be the problem.
CollisionWorld collisionWorld = World.DefaultGameObjectInjectionWorld.GetExistingSystem<BuildPhysicsWorld>().PhysicsWorld.CollisionWorld;
collisionWorld.CalculateDistance(new PointDistanceInput() {
Filter = new CollisionFilter() {
BelongsTo = 1 << 1, CollidesWith = ~0u, GroupIndex = 0
},
MaxDistance = 50, Position = position
}, out DistanceHit hit);
if (hit.Entity != Entity.Null) UnityEngine.Debug.Log(hit.Distance);
This is how it's set on the entities I want to find.
The debugged distance is always -0.5 for some reason.
karmic basin
Try bitmask 1 << 0 ? If I'm not mistaken
odd cipher
Nope didn't work either
karmic basin
Alright and when you set to everything in Inspector and in filter it works as expected ?
odd cipher
I'm unfamiliar with bitmasking but I'm guessing ~0u means everything. If so, no it doesn't work either. It might be that -0.5 is the distance to the ground entity.
karmic basin
yeah it's all 1's on a Byte so everything
Shot in the dark, do you have objects inside each other ?
odd cipher
No
karmic basin
Just to pinpoint the problem, try Filter = CollisionFilter.Default ?
odd cipher
Nope same thing
karmic basin
Yeah maybe the CollideWith everything grabs the ground then...
try 1 << 1 for the COllidesWith bitmask ?
sorry too lazy to launch Unity
odd cipher
Now it looks like this Filter = new CollisionFilter() { BelongsTo = 1 << 0, CollidesWith = 1 << 1, GroupIndex = 0 }
though no difference
karmic basin
Filter = new CollisionFilter() { BelongsTo = ~0u, CollidesWith = 1 << 1, GroupIndex = 0 }
odd cipher
Didnt work either.
karmic basin
I'm confused right now. I'd have to try myself to find source of the problem.
Wait if it's unsigned it supposed to be 1u << 1, could you try that ?
but I thinnk that wont help
odd cipher
nope, no difference
karmic basin
I you debug log hit.Entity it says it's the ground ?
odd cipher
I'm not sure how to differentiate it, it says its (3:1)
karmic basin
iit's the index in your entity debugger window
odd cipher
I'm guessing it's referring to a entity with index 3 then?
karmic basin
yeah it should be the third in your entity debugger
odd cipher
if its the one with index 3 then it's referring to itself.
karmic basin
ok so distance starts from center position of entity and collides with itself... we should ignore layer 1
Just to make sure, you have an entity looking for food, so you distance check on your Layer 1 ?
odd cipher
Yes
karmic basin
OK maybe I'll try myself later (Unity not installed on my new SSD right now)
stoic monolith
How do u deal with nativearray has not been disposed when exiting play mode?
I tried to dispose them in OnDestroy (and calling Complete first if needed) but still throws those error
amber flicker
I think you may potentially have issues if they're static but if not, you should be able to just dispose them - any better if you use OnStopRunning() (I think that's what it's called)?
tbh I'd expect OnDestroy to work fine - do you have a small repro?
amber flicker
virtual? Isn't this in a system? Is that ever being called?
amber flicker
if it was in a system I'd expect to see protected override void OnDestroy() - if that's not in a system then yea that's different
stoic monolith
Weird i cant recreate it now @_@
I thought it only happens when i Pause, and then stop Play (instead of just stop Play)
But yea, not happening anymore
odd cipher
How would I set specific indexes in a DynamicBuffer in a Parallel ForEach? ```csharp
Entities.ForEach((ref Translation translation, ref DynamicBuffer<InputNeuronData> inputNeuronData, in HealthData healthData, in DNAData dnaData) =>
inputNeuronData[0].SetNeuronValue(ref inputNeuronData, 0, healthData.energy);
inputNeuronData[1].SetNeuronValue(ref inputNeuronData, 1, closestFoodDistance);
}).ScheduleParallel();
I'm trying this but it doesn't work due to racing conditions. (Cleared up some of the code for the snippet, some missing variables).SetNeuronValue() is just a quick short cut to make the code shorter
public void SetNeuronValue(ref DynamicBuffer<InputNeuronData> neuronData, int index, float value) {
neuron.value = value;
neuronData[index] = this;
}
@odd cipher For the -0.5 value earlier i did some tests: the way I understand it, it gives you the distance you would have to move the collided entity so it stays at the surface of the other entity collider, instead of getting inside it.
It's negative so you go outwards the shape, and it's 0.5 because yo might test with a capsule of scale 1 for example ?
So from the center you have to move minus 0.5 to get the point on the surface.
odd cipher
@karmic basin I'm not sure I understand, though the entities that are trying to find targets are capsules of size 1 and the targets themselves are small cubes
karmic basin
Im gonna show you a screenshot
odd cipher
Alright
karmic basin
your food is the yellow sphere (scale of 1) so you would have to move -0.5 unit from center to be at the purple point
if your player would like to collide with it
In the end it's not what you're looking for
odd cipher
Ah yeah
karmic basin
I still think a distance check and eventually an octree for performance is the way to go
or an overlapSphere
odd cipher
The problem is I don't know how to do either of those things. I have a usual distance check against all food entities but it's verryyy expensive and doesn't really allow for a max distance.
odd cipher
Yeah, in the thousands.
karmic basin
ok I see
did you have time to try to jobify it and use burst ?
or you just dont want to try that route ?
odd cipher
I haven't been able to get it to work with Burst no, but I'm sure it's possible. Not exactly sure how though, I can share the code if you want it.
karmic basin
Nah I wont go this far 🙂 just giving you ideas
odd cipher
Hm well, I'll try and get the already existing method I have to work with Burst and see from there.
odd cipher
Yeah no, I'm completely stuck.
karmic basin
You can keep this (or do the spherecollider way) for now, knowing you will be able to optimize later when you're more confident with ECS
the most important at the beginning is that it works
Also you can look at the official Unity Boids demo to get more inspiration
this one has A LOT of boilerplate though and probably outdated now
I'll do an octree for my own project, but not before next year sorry
odd cipher
Hm yeah, I looked at the boids example and it's quite out of my expertise. I'll take a break from trying to optimize it for now and focus on other things. I'll come back to it later I suppose.
karmic basin
yeah as long as it work you can keep you project momentuum 🙂
frigid onyx
Is there any means to run a system only when a query does not return any matches?
.WithNone<>() will return every entity that doesn't have a given component, that's not going to work.
I'm looking for a RequireForUpdate() where the EntityQuery result length == 0. Like oh, hey, geeze, an entity with such-and-such component doesn't exist, I'm going to go build one
karmic basin
Do the query with those components as usual, then count them and early-exit if you find any ?
Or encapsulate in an if statement
frigid onyx
Yeah, it's just annoying to have to have the system running at all, checking every frame when this is a really rare occurrence in the game's logic
karmic basin
That wont overload your game
If it really is that rare, you could check count only when destroying these entites for example, because otherwise tehre's no way the count change
frigid onyx
I'm going to try it the first way you suggested, in the OnUpdate do a CalculateEntityCount() and then only run if I don't find any that match. I'm probably just overthinking it.
thanks
hollow sorrel
if you just want to check any matches you can just query.IsEmpty, it's more efficient than calculatecount
karmic basin
Yeah dont try to optimize until you see it in the Profiler
hollow sorrel
and also it's pretty much the same what systems currently do to detect if they should run or not
even if you think a system doesn't "run" because it doesn't meet its query requirements, it's actually still doing an onupdate just with a check for if the query is empty or not, before checking if it should do the user onupdate
karmic basin
and also it's pretty much the same what systems currently do to detect if they s...
You saw that from the source ?
hollow sorrel
yeah
karmic basin
nice
hollow sorrel
oh seems they're actually using query.IsEmptyIgnoreFilter which should be even faster because it ignores filters, but not sure what filters means in this case
frigid onyx
Awesome, thanks
Interesting. Apparently when you destroy an entity, it doesn't automatically destroy its children? Or am I doing something wrong?
zenith wyvern
Only if they're in a linkedentitygroup
safe lintel
Need linkedentitygroup to include children and any other entities you want to link in destruction or instantiation
zenith wyvern
Also it's a bit weird, the first entity in the buffer needs to be the "parent"
compact robin
Yo, is there anyway to copy a collider of an entity to another?
zenith wyvern
Assuming the collider is just a component, just assign the collider to a variable and pass it to SetComponent
compact robin
So would it copy the shape over
Like say if its a box collider
And the other entity's a sphere collider
zenith wyvern
Oh I'm not sure, I haven't messed with the physics system too much. Based on my limited knowledge of it yes i believe it would
compact robin
Oh ok thanks dude
zenith wyvern
If I understand it right it would overwrite the shape, since the "shape" is just stored as a header on the component
compact robin
Wow epic
Wait does that mean we can no longer have two types of colliders on a single obj
Not talking about nested ones in children
zenith wyvern
I don't know much about it but no I don't think you could. Unity's ECS has a hard limit of one component type per entity, and all physics shapes share the same component
But the physics system definitely does do compound colliders, so you'd have to do some digging to see how they do it
Like if you create a gameobject physics shape with multiple colliders, convert it and see what the component/entity structure looks like
karmic basin
Yeah I dont know how they would convert it, because they incite you to build compound GOs for colliders
glacial berry
Does anyone here know if Shader Graph with Visual Effect target should work on URP? (https://forum.unity.com/threads/simple-shader-graph-does-not-generate-a-visual-effect-shader.1011460/)
karmic basin
Did you ask in #archived-shaders ?
glacial berry
Did you ask in <#497874081329184799> ?
Not yet – I see now that they also discuss the Shader Graph and not just handcrafted shaders. Thanks for the pointer!
karmic basin
Yo Mr K, does PhysicsWorld store the transform of all entities?
I dont know. But you can access the Translation, Rotation, LocalToWorld, ... Components on the Entity itself
karmic basin
Translation is position
Transform is pos + rot + scale
scale is not yet exposed as far as I know, but you can mess with the transform matrix
Still trying to duplicate entire worlds ? 🙂
karmic basin
looks like there's a scale component now :p
compact robin
Translation is position
Yeah I meant this
So in this case
Does PhysicsWorld store ALL Translations?
Cuz I find that a waste
Say if I have thousands of ents
But only like 20 are players
And as such, require rollback
Wouldn't it be a waste to store the entire physicsworld
Per tick
karmic basin
Well if you want your players to collide with other ents (ants?) they should live in the same world ?
compact robin
Yes I want them to collide
But remember the rollback system
We spoke about yesterday
I don't have to rollback certain stuff
Especially static objs
They still need to collide
But I don't need to store their positional data
karmic basin
You still clone the whole relevant physics world, then update ECS data on the cloned world I guess
Dunno never tried
I guess it's not that simple
compact robin
No the thing is
Cloning physicsworld works
But I think it includes lots of unnecessary data
I only need positional datas of certain entities
They account for less than 5% of the total entity count
Which I think is why I wanted to make a simulation world
karmic basin
Yeah. I don't remember what we talked about yesterday (my memory is as crap as this) but I wouldnt clone. I would just have an authoritative server and client update positions without asking questions
compact robin
You mind if I recap?
karmic basin
Sure go ahead
compact robin
Ok
So basically
When there's network connection involved
There will always be latency
As such, sent reqs are always behind server time
So the server needs to store data every tick
So that it can rollback
Say 1 tick is around 25 ms
And the round trip is 100 ms
So it would take around 50 ms for req to reach server
That means the data is 2 ticks behind server time
So the server would rollback to data 2 ticks from before
So the suggestion yesterday was to clone physicsworld every tick
Which works
But if physicsworld contains translation and velocity data of ALL entities
I find that its a waste
Say I have 10 k entities
And only 20 of them are players
I don't have to store data of non-players
Since they are mostly static
I only need to store data for stuff I shoot
karmic basin
Ok so it really is a network concern
karmic basin
I dont see how you problem is different from other games
compact robin
It isn't
The thing is
If physicsworld stores everything
I might as well make a new world
And then send required data for simulation to it
And simulate there
Instead of storing physicsworld every tick
So basically players have a dynamic buffer of prev datas
karmic basin
I'm really not fan of cloning the world each time you receive a network message
compact robin
No
Its only once
I reuse the world
The world pools entities
And whenever I need to simulate
I send a set of data for the particular tick
To the world
It takes an entity in pool
Sets its component datas
And a raycast is performed
To see if stuff hits
That saves memory cuz I just have to store prev tick data for the 20 players
karmic basin
DId you try setting the component data but on a non-cloned world ?
compact robin
DId you try setting the component data but on a non-cloned world ?
That's not what I want since I want simulation to continue
In the main world
compact robin
That's not what I want
karmic basin
That's what I dont understand in your game
compact robin
Current world should keep ticking
And never go back
Whereas a separate world
Is responsible for going back in time
And verifying if a raycast would hit
At a given tick
karmic basin
oh yeah because different latencies
compact robin
Yes
karmic basin
I'm tired -_-
compact robin
It goes back by Round trip / 2 ms
Storing physicsworld is a cool concept
But it stores a lot of irrelevant data
Say minecraft
I would ideally have each block as an entity
But I don't need them to store prev pos
Cuz they are mostly static
And I dont shoot them
I'm not saying cloning and storing physicworlds don't work
I'm trying to find a better way
karmic basin
I would need to check again the DOTS online shooter demo to remember how they manage that
compact robin
I would need to check again the DOTS online shooter demo to remember how they ma...
According to the dude named script yesterday
They have something called PhysicsWorldHistory
karmic basin
I think they dont care and override the world for everyone
with interpolating and such
compact robin
Which is basically cloning and storing physicsworld every tick
Which is inefficient for my case
Since it stores a lot of redundant data ( Or at least I think so )
karmic basin
I never saw that, try it
karmic basin
I know of PhysicsWorld.Bodies and DynamicBodies (rigidbodies)
karmic basin
CHeck inside PhysicsWorld.DynamicBodies ?
compact robin
No what Im saying is
Say if you have 10 k entities
PhysicsWorld would contain data for all 10k ents
I think
So whenever I clone
it would clone all the 10k data
When I only need like 20 of them
So my current plan is -
-
Players have dynamic buffers of a certain size ( Based on max amount of ticks you should rollback )
-
A raycast req is received, which contains a tick number
-
A job finds all entities with the buffer, and then grabs the relevant tick data, then stores them in a native array
-
Data is sent to simulation world, which sets data to the ents
-
Simulation world does a raycast
I think that's better since I only need to like store 20 sets of data every tick
As opposed to the entire physicsworld
Also storing just the physicsworld is flawed in the sense that
Should I require other data
Say data of a comp previously
Storing a physicsworld wouldn't help
What I plan to do is to store my own struct of tick data
karmic basin
PhysicsWorld.NumBodies (total)
PhysicsWorld.NumStaticBodies (PhysicsShape, no PhysicsBody component)
PhysicsWorld.NumDynamicBodies (PhysicsShape + PhysicsBody)
PhysicsWorld.Bodies -> NativeArray of rigibodies
PhysicsWorld.DynamicBodies
do these help ?
compact robin
No because when you do PhysicsWorld.Clone(), all of those get cloned
I just need players' data
karmic basin
then only clone dynamic ones ? but it means your own implementation
compact robin
then only clone dynamic ones ? but it means your own implementation
Is that even possible?
And how would I do physicsworld.raycast then
Besides physicsworld doesn't include custom component data I believe
karmic basin
I mean working with data and not cloning
compact robin
So I can't check for previous state
compact robin
I mean working with data and not cloning
Yeah but I can't just do a raycast against a set of int3 s
I need the physicsworld
If I clone to another world, then I could use the physicsworld of that world
To raycast
And I only copy 20 set of data
Instead of 10k
I can also copy custom component data
Say if a player is invulnerable in tick 20, but not in tick 21
amber flicker
Fwiw I think you'll have more luck on the dots netcode forums (unless you've already tried). Unless someone here has actually tried doing netcode and physics I think you'll be limited to fairly general advice. I'm surprised it the teams aren't thinking quite a lot about these kind of issues but perhaps I'm wrong. Apologies for not taking the time to fully understand your problem. Having not done any serious networking myself I lack the experience but I wonder if you're approach is a little untypical? I.e. I think you would normally send the users inputs to the server and the server would simulate (with rollback and prediction) then tell client whether e.g. a raycast hit.
compact robin
server would simulate (with rollback and prediction) is what I'm trying to achieve
So my plan is
So my current plan is -
1) Players have dynamic buffers of a certain size ( Based on max amount of ticks you should rollback )
2) A raycast req is received, which contains a tick number
3) A job finds all entities with the buffer, and then grabs the relevant tick data, then stores them in a native array
4) Data is sent to simulation world, which sets data to the ents
5) Simulation world does a raycast
ah so you're not using netcode and want to roll your own?
compact robin
Yes
According to a guy named Script
Their impl is
PhysicsWorldHistory
Which is basically cloning PhysicsWorld every tick
But I find it a waste
Cuz say if I have 10 k ents
And I only need to rollback 20 of em
Why would I want to clone data of all 10 k?
Besides the physicsworld approach constraints me to only physics related data
amber flicker
if they're physics bodies, how do you know they don't interact?
compact robin
Say minecraft
We have blocks
But we dont need to shoot them
Hence I dont have to rollback data
And as such, I don't have to store data about them
Every tick
Things like maps won't move
And are static
amber flicker
then why would they be in the physics world?
amber flicker
afaik... it contains a representation of all the colliders but doesn't contain e.g. meshes and all the entity stuff
but surely everything in a physics world can in theory interact with everything else in the world
compact robin
Yeah like their translation
But I don't need to store previous translations
Of static stuff
Only for stuff I need to rollback you see
In present time, I need data of all ents
But only specific ents need to be rollbacked
For instance, players
Because they can be shot
But due to latency, the req would always be behind server time
amber flicker
So.. this is a concern about performance right? Trying to minimise memory usage?
compact robin
Yes
Haha
Cloning physicsworld works
As mentioned earlier on
But have two main drawbacks
Or at least I think they do
- I have to clone all 10k
- If I need custom comp data, I need a separate collection
amber flicker
So out of these 10k, how many do you imagine being static?
amber flicker
I assume that any clone of physics world would just clone some blob data of the static colliders - which will likely just be a pointer
that could be worth asking on forums/checking if that would alleviate your concerns
is this a problem you've measured or theoretical?
amber flicker
Seems like a lot of work you're giving yourself if it doesn't prove to be a problem. I would also have expected the teams to have considered this.
I would check your assumptions on the forums.
compact robin
Not really I find it easier tbh
Cuz I can just copy entities to a separate world
And set their data
And simulate from there on
north bay
Do you actually want to simulate the rollbacked entities or only do queries on them?
compact robin
Raycast
And maybe simulate
and I may need to store prev data of some comp data
Which is why physicsworld may not work out
And I don't want to clone redundant data
north bay
That might be interesting to you: https://github.com/Unity-Technologies/FPSSample/blob/master/Assets/Scripts/Game/Modules/HitCollision/HitCollisionHistory.cs
They did a similar approach to what you suggested as your 'plan'.
compact robin
Like a separate world?
north bay
They didn't use a separate world, that was before Dots Physics. They had their own raycast implementation.
compact robin
So would my impl be better?
north bay
Idk
compact robin
I feel its much less work than cloning physicsworld every tick
Should I have a ton of entities
Which is the whole point of ECS
compact robin
Isn't it the same for cloning comp / entities
north bay
What do you mean?
north bay
Cloning the world doesn't iterate over the individual entities.
north bay
The data inside the collision world is already linear, cloning just copies the content of the CollisionWorld and DynamicWorld into a new location
compact robin
Like what about the copying process
Since I only have around 20 ents
Which can be rollbacked
Its not gonna be that slow as well
karmic basin
@north bay you were talking about that yesterday ?
https://github.com/Unity-Technologies/DOTSSample/blob/09543c800c4ab58f061db4a407c3f564dc04f734/Assets/Unity.Sample.Game/PhysicsHistory/PhysicsWorldHistory.cs
compact robin
Yes
north bay
Yea, they might did some changes to it compared to the NetCode version. Haven't checked that out
amber flicker
if most of those are static, I don't think it will create copies
compact robin
Idk what unity means by "static" tbh
My def of static is basically stuff that don't have to be rollbacked
Even though that's not what static means xd
north bay
You can also just copy your entities and do the approach that you suggested. It really just depends on your requirements.
compact robin
Nice
Oh yeah, do you think its faster to like say remove all components of an entity, and then set comps, or just create a brand new one with all the comps needed?
Sorry for the ton of qns btw
amber flicker
I'm not sure how those things equivalent? Likely creating an entity from scratch is fastest (provided you use an archetype and ideally batch create) than using e.g. 'RemoveComponent'
compact robin
Nice
Cuz I planned to pool ents in simulation world
And reuse them
But since such is the case, I should just destroy them all
And recreate
vagrant surge
@compact robin as a rule of thumb
changing an entity (adding/removing comp) costs the same as deleting the entity and creating a new one
compact robin
Or maybe pool them for similar archetypes
amber flicker
Caching an entity itself is a bit like caching an index of an array to my mind.
vagrant surge
and everything inside the ecs is already pooled, so its completely useless to try caching it
vagrant surge
an entity is literally only an integer
compact robin
With a certain archetype
Instead of destroying them
I could reuse them
If I need to simulate an ent of a similar arch
vagrant surge
but then you have to add code to check if the entities are alive or not
compact robin
an entity is literally only an integer
Yeah and version number
vagrant surge
so it becomes trickier
compact robin
I could store them in managed arrays
Like a queue
Where T is the particular arch
vagrant surge
ive done simulations where i was deleting and creating entities hundreds of times per second and there was no need for any pooling
sorry
hundreds of thousands
per second
compact robin
But if I can avoid deletion why not lol
vagrant surge
this is the scale we are talking about
because it costs more
to try to avoid deletion
than to just delete it
vagrant surge
full delete
vagrant surge
it is
vagrant surge
the problem is that removing comps is done "individually"
so you remove one component by component
deleting the entity "clears" the entire thing in 1 go
vagrant surge
im not fully sure if they added batching or something, but it wasnt there last time i looked
no
compact robin
Looks like I'm wrong
vagrant surge
in the unity ecs model creating and deleting is cheaper than adding components to an entity
compact robin
Because they have to move them to another chunk
vagrant surge
well, kinda bout the same
compact robin
Right?
vagrant surge
yes
compact robin
in the unity ecs model creating and deleting is cheaper than adding components t...
Is this under the assumption that I init them with a particular arch
vagrant surge
yes
compact robin
Ok nice
vagrant surge
you should allways init directly on the archetype
compact robin
Oh
vagrant surge
creating an entity and then modifying it is a lot more expensive
compact robin
I see I see
vagrant surge
as commented, each component change is a bit like destroying the entity and creating it into a different archetype
so if you create empty entity and add 2 comps, thats 3x more expensive than just creating it into the correct place from the start
compact robin
I just hope I don't run out of version numbers LOL
vagrant surge
its an int64 bruh
vagrant surge
literal heat death of the universe even if you create a billion a frame
vagrant surge
we are talking number-of-atoms-in-universe level huge
compact robin
Yeah looks like premature optimization to me
Oh yeah could you tell me if
RoomWorld.DestroySystem(RoomWorld.GetExistingSystem<PresentationSystemGroup>());
RoomWorld.DestroySystem(RoomWorld.GetExistingSystem<InitializationSystemGroup>());
This is a good idea
vagrant surge
that i dont really knowp
compact robin
If I don't need to visualize stuff
I know destroying presentation grp
Makes stuff invisible
Cuz no rendering
But I plan to run it in headless mode anyway
Idk what InitializationSystemGroup is for
But so far my tests conclude that OnCreate() still works
For systems
My default world has all the def systems, its just those worlds I manually create in which I'm trying to purge the systems from
karmic basin
- InitializationSystemGroup (updated at the end of the Initialization phase of the player loop)
BeginInitializationEntityCommandBufferSystem
CopyInitialTransformFromGameObjectSystem
SubSceneLiveLinkSystem
SubSceneStreamingSystem
EndInitializationEntityCommandBufferSystem
compact robin
Yeah Idk what those do
karmic basin
I think yo should keep it ?
compact robin
I believe its related to gameobject injection
But it should be fine since my def world has all 3 def system groups ( And its systems )
karmic basin
oh right probably
compact robin
The thing is
RoomWorld.DestroySystem(RoomWorld.GetExistingSystem<PresentationSystemGroup>());
RoomWorld.DestroySystem(RoomWorld.GetExistingSystem<InitializationSystemGroup>());
you'll see when you get an error :p
compact robin
When I dont have this
For each world
It creates a new debug drawing comp
To allow me to see stuff
But I dont need it
I just need the sim
Since its a headless server
So I think destroying RoomWorld.DestroySystem(RoomWorld.GetExistingSystem<PresentationSystemGroup>()); is safe
But idk about init
I need the sim group because it has all the systems responsible for physics simulations
I add my own custom systems to the group
so I can manually call update by doing World.Update()
karmic basin
I think you dont need to worry about empty system groups
karmic basin
they cost close to nothing
compact robin
I think you dont need to worry about empty system groups
They are not empty
The presentation grp renders stuff
Which is significant overhead I think
Say if I create a thousand worlds
Its gonna render stuff for all thousand
karmic basin
oh yeah because you cloned, right
compact robin
And it creates a debug drawer for each world
karmic basin
yeah I see
compact robin
oh yeah because you cloned, right
No
I don't think you can clone worlds
Well at least idk how
I was trying to find out how
RoomWorld = new World(Key);
var Systems = DefaultWorldInitialization.GetAllSystems(WorldSystemFilterFlags.Default);
DefaultWorldInitialization.AddSystemsToRootLevelSystemGroups(RoomWorld, Systems);
RoomWorld.EntityManager.MoveEntitiesFrom(World.DefaultGameObjectInjectionWorld.EntityManager);
var SysGrp = RoomWorld.GetOrCreateSystem<SimulationSystemGroup>();
//Destroy useless systems
RoomWorld.DestroySystem(RoomWorld.GetExistingSystem<PresentationSystemGroup>());
RoomWorld.DestroySystem(RoomWorld.GetExistingSystem<InitializationSystemGroup>());
var Sys = RoomWorld.GetOrCreateSystem<Test4System>();
SysGrp.AddSystemToUpdateList(Sys);
This is what I do
Ignore moventitiesfrom
I use that to test physics
karmic basin
Yeah I never tried that so really I dont know
I would just monitor with and without and let numbers talk if you're really concerned about it
compact robin
I see
I mean its def going to be faster without additional systems
The question is, would it break stuff
🧐
pliant pike
I don't suppose anyone can tell me how I avoid this error Attempted to access BufferTypeHandle<CellDataBuffer> which has been invalidated by a structural change.
when I'm just using this if(celldatasbuffer.IsEmpty) to read the buffer
zenith wyvern
Don't do any structural changes between creating the buffer and adding to it
Or accessing it in any way really
pliant pike
I'm trying to read from a buffer in a monobehaviour so how would I do it without a structural change
zenith wyvern
Keep a reference to the entity with the buffer, and only get the buffer through the entity reference and access/change it within the same function
pliant pike
I'm guessing that's not really compatible with using it in an OnDrawGizmos() 🤔
zenith wyvern
I don't see why not
Just verify the world is created any time you access it. I feel like DrawGizmos might try to run while ECS is initializing
pliant pike
DrawGizmos runs all the time in editor mode also
that's what I'm trying to get around
zenith wyvern
Yeah so just do if(!World.DefaultGameObjectInjectionWorld.IsCreated) return; at the start of OnDrawGizmos
You can't keep a reference to any ECS component or buffer. The only practical way to reference a part of an entity is through the entity
pliant pike
yeah its just a matter of making sure they are valid when I get them
thanks @zenith wyvern
compact robin
Yo guys, is there like a dynamicbuffer that overrides values once its internal buffers are full? As much as it sounds ironic
amber flicker
sounds like you want a circular buffer? You'll have to roll your own I believe but should be pretty straight-forward? Easiest I can think is dynamicbuffer with an additional index.
compact robin
Like a ringbuffer?
compact robin
Oh they are the same thing
Yeah in a sense
But I need something that is usable in jobs
So basically, a dynamicbuffer with int?
amber flicker
Off the top of my head, can't think of anything wrong with that 👍
compact robin
Hmm ok
Thanks again
Using a native array wouldn't work right? Since sizes may vary
amber flicker
dynamic buffer if you want it per entity, native array if you want to store it e.g. within a system. Depending how much you care about every micro second, one e.g. giant native array with a second that stored current index per array segment or something might be fastest? Though writing that out I find it hard to work out why you'd ever want that. Flat native arrays always win if you can work with them.
compact robin
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