How to for_each with groupby?

[vkensou]

I want to batch process objects with the same material and mesh. How should I do it?
sort group and then record batch's begin/end in an extra vector? Does entt support this immediately?

[skypjack]

I guess you want to pass around all components of a given type as a packed array? Remember that EnTT storage is paged by default, you still have to provide a page at a time in case. Do you know it?

[vkensou]

I guess you want to pass around all components of a given type as a packed array? Remember that EnTT storage is paged by default, you still have to provide a page at a time in case. Do you know it?

I want group entities by a value/a lambda, like opaque objects is group1 and transparent objects is group2, etc. Not group by component, but group by value.

[skypjack]

As in:

struct clazz {
    int foo{3};
    // ...
};

Gimme all the entities for which foois equal to 3?
No, EnTT doesn't support it out of the box unless you use something like the reactive storage and keep track of the entities of interest by checking a runtime value like this.
However, it smells of an XY-problem to me.

[vkensou]

Thank you for your reply. It seems that I need to think deeply.