Game Development

4:00 AM

That would be the same principle though. Create a method for each side of the cube that adds the sides vertices to the list verticesToDraw

Sean Middleditch

@VaughanHilts: you can't fully avoid heap allocations, especially in C#; just be mindful of them and your algorithms. if you do have objects like that, try to do everything you can in one pass, instead of iterating over the list of objects multiple times

Vaughan Hilts

Haha, y eah.. I need to change some of that, too

Sean Middleditch

one of the reasons the "pros" stick to C++ for core engine work is that we can have full classes allocated and arranged any damn way we please, which is important for games of larger scale

Vaughan Hilts

Need to change systems to have an updateEntity function

Instead of in update, iterating the list for each of them

Sean Middleditch

You mean in an ECS kind of design?

Vaughan Hilts

4:02 AM

Aye

Sean Middleditch

the idea there is you put each component in its own systems' list, so you iterate over each type of component once in a single run

depending on the component, you can make it a struct, too

Vaughan Hilts

Structs can't inherit.

Which makes the code a bit hard to generalize =)

Especailly things like 'add component'

And yes, they do

Sean Middleditch

you don't need inheritance... really. if you're doing a pure ECS, you just tell the system "make a new component for object id x"

Vaughan Hilts

How does the system know what it is?

Sean Middleditch

you don't need to reference the component, you just need that id

Vaughan Hilts

4:05 AM

Like, when the system goes to consume it?

Sean Middleditch

the struct contains a copy of that id

Vaughan Hilts

I mean, in your update loop

Sean Middleditch

i'm not sure I understand what you're asking... just iterate over all the components in the system's component array

Vaughan Hilts

Wouldn't you need multiple arrays though?

So if a system needed all movement components

Er

transform

And sprite components

Sean Middleditch

each system has one array for the components it manages

Vaughan Hilts

4:06 AM

How do you factor them into the same list, though?

Sean Middleditch

how do you mean?

Vaughan Hilts

foreach(Component c in components)
{
// Try and figure out what something is...
}

Sean Middleditch

why do you need to know "what it is" ?

all the components in a particular array are of the same type

Vaughan Hilts

If this is a drawing system, for example.

I need transform AND sprite components for a given entity

Sean Middleditch

ah, ok, sure

so each component struct also includes its id

so you can do something like matrix = TransformSystem.GetAt(draw_component.id)

Vaughan Hilts

4:10 AM

Yeah, if you don't mind coupling the systems.

Sean Middleditch

you have already coupled the systems if your draw system needs both components

Vaughan Hilts

I suppos.. I do something like that already, I guess

It just looks something more like this

for(Entity e in registeredEntities)
{
transformComponent = e.getComponent(typeof(TransformComponent));
.. get draw component
draw();
}

Which was the best way I could think of that time of writing it.

Internally, components are just stored in a hash map organized by type

So retrieval is instant

Sean Middleditch

i'm not saying do everything like this. this is my problem with ECS. it tries to teach yuo that ther eis but one way to do it all. especially hilarious given that it's champion engine is Artemis, in Java, which has nothing like C#'s struct. also hilarious that they put a video of me on their front page a couple months back talking at length about how real data-oriented design is done.

@VaughanHilts: that code is not "instant" - it's a hash map lookup. that is going to be a good deal slower than an index into an array. not exponentially slower, but still slower.

Vaughan Hilts

Sorry, I meant "constant"

Sean Middleditch

sure

one thing you learn in game development though is that not all O(1) are the same

Vaughan Hilts

4:14 AM

Oh, of course not.

One unit of time is not the same as another unit

Constant just guarentees.. constant for a particular data set :)

Situations vary

Is that video any good?

Sean Middleditch

it's okay

they're talks I give to underclassmen, generally without any rehearsal

Vaughan Hilts

Oh DOD

That's optimizing memory layouts

Sean Middleditch

basically

also just designing your code around the data it operates on instead of around excessive abstractions like OOP tends to promote

Vaughan Hilts

Yeah, I defintely over abstract a lot..

But I do like it, it gives a degree of flexibility.

Sean Middleditch

really, just read the BitSquid blog at bitsquid.blogspot.com if you are interested in that approach - those guys are insanely good at what they do

yeah, it's a trade off

you can take it too far

or not far enough

... all four of my spinning disks just went offline from SMART errors.

Vaughan Hilts

4:18 AM

I read some of their articles. :)

Haha

False alarm?

Sean Middleditch

I think this motherboard might be junk

Vaughan Hilts

That'd be a shame haha

Sean Middleditch

I just bought a new Haswell-based rig, already had to return the GPU, wouldn't be surprised with my luck if the mobo's disk controller is bad

i have the worst luck with hardare, you have no idea

Vaughan Hilts

P.S: Thanks for the insight - I think the best way to figure out is just read, fail, fix and learn :)

lol

Sean Middleditch

i mean, like, bad. of everything I buy, i Swear i end up having to return like 70% of it

Vaughan Hilts

4:19 AM

My uncle just installed a new 1k RAID card

8 drives

3 failed with a hardware alarm in 30 days

Sean Middleditch

can i presume you're a Linux fan from your avatar icon?

yeah, if I boguth all these drives together, I'd suspect a bad batch of drives - it happens a lot

Vaughan Hilts

Actually, I primairly use OSX and Windows... but the penguin is cute :)\

Sean Middleditch

these were all different drives bought at different times, though

Vaughan Hilts

Yeah, his were bought from the same retail store all at once

In a batch

Sean Middleditch

At scale you just start assuming that X% of drives you buy in a batch will be bad and plan for it

Vaughan Hilts

4:22 AM

I've never had a drive fail on me.

I replace mine after 1-2 years, though usually.

Sean Middleditch

... this is a bit different. in any case, Borderlands 2 was on one of those drives and I haven't finished the Tiny Tina DLC yet, time to go figure out what's up

Vaughan Hilts

I've been meaning to get around to building a RAID array

It's just finding a CPU that isn't a power whore

Then at least when something like this happens, you can keep playing for a bit ;)

Sean Middleditch

well, i think it was the controller, not the drives... i've seen raid controllers go bad. even destroy the drives attached to them. time to power down and inspect hardware bits, peace out

Vaughan Hilts

LOL

That's insane.

Take care, hope your drives are fine

Kikaimaru

5:31 AM

@VaughanHilts i think its much better to register components, and not entities, and components can have normal field with references to other compoenents, so no lookups

like when you have ModelRenderer components its logical that it will have reference to Transform component (because it really doesnt make sense without it) so if you register ModelRenderer in your RendererSystem and go through all ModelRenderers, and get world matrix from modelRenderer.Transform.World

Tordin

7:30 AM

Morning!

Alex M.

11:30 AM

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