Method DEFINE_VMETHOD_INTERPOSE

plugins/add-spatter.cpp:219–274

    typedef improvement_product interpose_base;

    DEFINE_VMETHOD_INTERPOSE(
        void, produce,
        (df::unit *unit,
         std::vector<df::reaction_product*> *out_products,
         std::vector<df::item*> *out_items,
         std::vector<df::reaction_reagent*> *in_reag,
         std::vector<df::item*> *in_items,
         int32_t quantity, df::job_skill skill,
         int32_t quality, df::historical_entity *entity, df::world_site *site, std::vector<df::item *> *improv_items)
    ) {
        if (auto product = products[this])
        {
            auto object = find_item(product->object, in_reag, in_items);
            auto material = find_item(product->material, in_reag, in_items);

            if (object && (material || !product->material.reagent))
            {
                using namespace df::enums::improvement_type;

                int mattype, matindex;
                find_material(&mattype, &matindex, material, product->material);

                df::matter_state state = matter_state::Liquid;

                switch (improvement_type)
                {
                case COVERED:
                    if (flags.is_set(reaction_product_improvement_flags::GLAZED))
                        state = matter_state::Solid;
                    break;
                case BANDS:
                    state = matter_state::Paste;
                    break;
                case SPIKES:
                    state = matter_state::Powder;
                    break;
                default:
                    break;
                }

                int rating = unit ? Units::getEffectiveSkill(unit, skill) : 0;
                int size = int(probability*(1.0f + 0.06f*rating)); // +90% at legendary

                object->addContaminant(
                    mattype, matindex, state,
                    object->getTemperature(),
                    size, -1,
                    0x8000 // not washed by water, and 'clean items' safe.
                );
            }

            return;
        }

        INTERPOSE_NEXT(produce)(unit, out_products, out_items, in_reag, in_items, quantity, skill, quality, entity, site, improv_items);
    }
};