builder_i.hpp

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#pragma once
 
#include "../filter/builder_i.hpp"
 
namespace flecs {
 
template<typename Base, typename ... Components>
struct observer_builder_i : filter_builder_i<Base, Components ...> {
    using BaseClass = filter_builder_i<Base, Components ...>;
    observer_builder_i()
        : BaseClass(nullptr)
        , m_desc(nullptr)
        , m_event_count(0) { }
 
    observer_builder_i(ecs_observer_desc_t *desc) 
        : BaseClass(&desc->filter)
        , m_desc(desc)
        , m_event_count(0) { }
 
    Base& event(entity_t evt) {
        m_desc->events[m_event_count ++] = evt;
        return *this;
    }
 
    template <typename E>
    Base& event() {
        m_desc->events[m_event_count ++] = _::cpp_type<E>().id(world_v());
        return *this;
    }
 
    Base& yield_existing(bool value = true) {
        m_desc->yield_existing = value;
        return *this;
    }
 
    Base& ctx(void *ptr) {
        m_desc->ctx = ptr;
        return *this;
    }
 
    Base& run(ecs_iter_action_t action) {
        m_desc->run = action;
        return *this;
    }
 
protected:
    virtual flecs::world_t* world_v() = 0;
 
private:
    operator Base&() {
        return *static_cast<Base*>(this);
    }
 
    ecs_observer_desc_t *m_desc;
    int32_t m_event_count;
};
 
}