Framework to allow burnt items to drop byproducts on destruction

[NotFuji]

closes #22983

Items destroyed by fire drop items; included example is wooden items leaving wood ash when burned.

Number of products depends on the weight of the burned item, the fuel efficiency for the reaction, and the amount of the item that is made of flammable material. (Since how much of each material is present in an item isn't defined, it's assumed that each is in equal parts by weight. IE, a tool made of wood and steel is assumed to be 50% wood and 50% steel.

Modular as to handle items made from different materials, including multiple.

[smolbird]

Byproduct as a property material definitions can cite in JSON might be more useful overall, but interesting idea anyway.

[BevapDin]

Please move the new code into a separate function. I don't want to scroll horizontal while reading code.

[BevapDin]

Please use empty() when you check a container for emptieness.

[BevapDin]

Why is this using the type weight instead of the item weight item::weigth. Those are not necessarily the same same (e.g. for items with dynamic weight (corpses)). The function has a parameter to exclude the weight of its contents.

[BevapDin]

You don't need a full item instance to get the item type, you can use item::find_item instead.

[BevapDin]

Why two separate vectors when you apparently need them synchronized (element N in one belongs to element N in the other). Use a single vector containing std::pair<itype_id, int> instead.

Actually, why the separate step of gathering type and count and later creating the item? You can create the item directly inside the if branch below.

And when you call an emplace function on a container, the parameters are forwarded to the constructor of the contained type. You don't need to create the instance yourself. In other words: write emplace_back( "item_type", turn, charges ) and the container will create an item for you.

[NotFuji]

Added requested changes, and moved byproduct definitions to JSON

[BevapDin]

Please use 4 space characters instead of a tab character.

[BevapDin]

Does the function really need a reference to a non-const item?

[smolbird]

Allowing for materials to yield different burn by-products. Main use would be for items that should melt rather than burn. Future use might be for tin and other metals that fire could melt. Having wooden-handled items return a blade, scrap metal, etc would be viable too.

[BevapDin]

Instead of adding a level of indentation to the whole function body, you can return from the function when the condition is not true - e.g. if( all_mats.empty() ) { return; } or you can continue in a loop.

Our (style)[doc/CODE_STYLE.md] requires the opening bracket to be on the same line as the if clause.

[BevapDin]

burn_products is called twice (here and above), calling it before the if clause and using all_bp in the condition would be more efficient. But you don't need this variable (and the emptiness check) at all. It's perfectly valid to iterate over an empty container, and it's valid to iterator over a function result:

for( auto &bp : mat->burn_products() ) {

[BevapDin]

This information is quite useful, but it does not belong here. People that want to edit JSON files won't search here. And when the format is actually changed, the loading code in "material.cpp" is updated, but most likely not the comment on this function. It might be more suitable as comment for material_type::_burn_products.

[kevingranade]

This is the remaining astyle regression.

[Coolthulhu]

Style: should be on 3 lines (if(){, body, }).

[Coolthulhu]

Style: don't omit braces

[Coolthulhu]

You could make it a reference, to avoid copying the result.

[Coolthulhu]

Plastic is flammable too

[Coolthulhu]

You've got a tab here

[Coolthulhu]

Tab

[Night-Pryanik]

Should be like if( all_mats.empty() ) {. Also excess space after curly bracket.