[Question] Directly accessing packed array

[HexitCZ]

Hi,
I recently stumbled upon this library and so far I am loving it!
But I managed to find a problem I am not able to resolve.
In short, I am trying to make a 2D game in raylib with many entities (thousands) and I pretty much have to utilize instanced rendering for it, but I am unable to manage to get a contiguous array (of transforms for the drawcall) from EnTT and I am still unsure if it's even possible.

1. I have entities with CustomTransform component (which is just a struct with a matrix member variable).
2. I get the storage_type object from the registry of the CustomTransform component.
3. Then I get the packed array with data() from the storage.

• And this is where my tries fail. I need the packed array of the transforms (matrices) to pass into the drawcall function. I tried casting it to const pointer array of the component, but then if I read the data with a loop for example, I get garbage data.

            auto& transform_storage = registry.storage<CustomTransform>();
            const auto* transformData = (const CustomTransform*)(transform_storage.data());
            //transformData contains only garbage or seemingly random/uninitialized data

I tried sorting, doing the same with groups, but to no avail.

Thank you and sorry in advance if this is dumb question, but I had to ask for my own sanity.

[skypjack]

Elements in a storage are paged. You don't have everything fully contiguous. Instead, you've fully contiguous pages of components. You can iterate them and pass one page at a time to the renderer.
component_traits<Type, Entity>::page_type is the page size of the given type (which is customizable btw). This function can give you the inspiration probably. It searches an element in the storage, one page at a time. Well, sort of 😅 but it does something close to what you need at least.

[HexitCZ]

Thank you for such a quick response!
I'll look more closer into that, thank you!

[skypjack]

Feel free to reach out if you have doubts. 👍

[skypjack]

Let me know if there is anything else I can do. Otherwise, I'm closing the issue soon. 👍

[HexitCZ]

Hi, sorry for keeping this unawnsered. I rethought the architecture I though wanted and it occured to me that I don't need the fully contiguous data and then I got occupied with something else. Nevertheless thank you for everything nd sorry again.

Early Merry Christmas!