Generated greedy mesh improper behaviour

[umbral wigeon]

See attached image. Faces rendered are wrong.
I also randomly get a message like the following (which is coming from rapier, probably while generating the collider):

thread 'Compute Task Pool (3)' panicked at 'index out of bounds: the len is 512836 but the index is 512840', /Users/visual/.cargo/registry/src/github.com-1ecc6299db9ec823/parry3d-0.10.0/src/shape/trimesh.rs:502:17

Code is here: https://github.com/ChefKissInc/CaveGame/blob/master/src/plugins/terrain/world.rs

[high stone]

I think this happens when the AlphaMode is set to Blend. Try Opaque

[umbral wigeon]

the faces are drawing the wrong way

it's supposed to be cubes

[high stone]

Oh, you're right 😅
It looked very similar to a different bug :v

[modest coyote]

You might be able to reverse your triangle indices and it'll work correctly.

Winding order is important

[umbral wigeon]

uhm, the triangles are correct, the problem is that the wrong sides get enabled and disabled

see the big get_voxel_data_for function

[umbral wigeon]

(there's probably a lot of flaws with this code)

[wicked verge]

Yea that's what winding order does. Triangles winded the wrong way around are hidden, this means you only need to draw half the number of triangles, however, if you wind them the wrong way around you see only the back instead of only the front

[umbral wigeon]

As in, left side of the cube instead of the top for example

not 50% of the cube side is not visible

or triangles flipped

[wicked verge]

Yea some traingles seem to be winded differently from others

The bottom is flipped but left/right is correct

Back/front seems to also be flipped

[umbral wigeon]

did that, it's slightly better, but there's still an issue

[wicked verge]

Ok can you post a image what it looks like now?

[umbral wigeon]

here you go

[wicked verge]

Still seems the sides are flipped

[umbral wigeon]

is this not what you meant

[wicked verge]

Are you using a custom shader?

[umbral wigeon]

no custom shader

[wicked verge]

The lighting seems off too but IDK

[umbral wigeon]

i have ambient lighting

[wicked verge]

No, that's not what I meant, change the order of the verticies, not their sign

[wicked verge]

If you add a direcitonal light the normals will be easier to see

[umbral wigeon]

but why? it was fine before i added the face checks

[wicked verge]

Winding order = order of verticies

[umbral wigeon]

if i switch the .filter(...) to always return true, it displays fine

[wicked verge]

Oh that might be voxel code then

My bad it looks just like a winding issue

[umbral wigeon]

i copied the vertices, normals, and uvs from bevy's cube shape

the sides were commented like in my code, and i assumed that by front, back, etc, they meant in the actual axis

[wicked verge]

Is there a way for you to color the sides depending on what cube they are from? So it's easier to see if you are filtering the wrong cubes of positioning the faces of each cube incorrectly?

[umbral wigeon]

oh, there is actually another code bug

i wasn't skipping drawing air blocks

here it is now

[umbral wigeon]

i could add some kind of texture, idk

[wicked verge]

That looks a lot better

[umbral wigeon]

any ideas now

[wicked verge]

Can you send a piture more zoomed in one one of the blocks please?

[umbral wigeon]

sure

[umbral wigeon]

does this help

and this

[wicked verge]

So I'm looking at your code and not seeing any obvious issues, though I'm not looking very closely

What's odd is the right faces seem to work very consistently

But the others all sometimes appear correct and sometimes not

In the top screnshot the front faces seem ok on the left half of the screen but missing completely on the right

[umbral wigeon]

i'm like extremely new to all this stuff; rendering and the vertices, triangles, the coordinate system, bevy itself, etc so i am clueless

[wicked verge]

So I'm unfortunalty not sure what the issue is, but if I where you I'd reduce your scene to be very small, maybe 2x2x2. Then instead of random generation manually try some combinations of faces to see if you can find a pattern what works and what not

[umbral wigeon]

i do not understand

[wicked verge]

Like right now you are trying a huge map. I know the faces are in the wrong place but I don't know where they are supposed to be. If you use a tiny map, as small as you can, like 2 by 2 by 2 or 3 by 3 by 3 cells it will be much easier to see

[umbral wigeon]

like this?

that's 4x4x4

[wicked verge]

Also you can use a debugger or print the values. See which ones are not what you expect

[umbral wigeon]

i don't know what i am expecting in values

i think there is some kind of relation between the vertices and the world's positions

that i am not getting

[umbral wigeon]

i projected the "top" side in my head with the values

the top is actually the front

why'd bevy mislabel the data

@wicked verge there we go

Top/Bottom was actually Front/Back and Front/Back was actually Top/Bottom

thanks for getting me into thinking more through the code

i have one minor issue though, if i set the chunk width/height to 64 i get a "bus error" and from macos "application exited unexpectedly" for some reason
but this doesn't seem related

thread 'Compute Task Pool (0)' has overflowed its stack
fatal runtime error: stack overflow
[1] 83810 abort cargo run
interesting
EDIT: nvm, fixed by using a Vec<Vec<Vec<>>> instead of nested arrays

[wicked verge]

Nice

[wicked verge]

If you ever want to improve performance switch back to a array for better cache locality, but the only way to do that is unsafe code

it's a unfortunate rust limiation

[pseudo night]

What's the limitation?