AttributeProjection.h

浏览该文件的文档.

#pragma once
#include "common/Export.h"
 
 
#include "attributes/AttributeSet.h"
#include "common/ECS.h"
#include "common/Result.h"
#include "common/Revision.h"
 
#include <span>
#include <string>
#include <string_view>
#include <vector>
 
namespace eve::attributes {
 
struct AttributeSnapshotBase {
    AttributeId attribute;
    double      base = 0.0;
};
 
struct AttributeProjectionSnapshot {
    ecs::EntityHandle                  owner{};
    Revision                           capturedRevision = Revision::zero();
    std::vector<AttributeSnapshotBase> bases;
    std::vector<AttributeModifier>     modifiers;
};
 
class EVENGINE_API_FOUNDATION AttributeProjection {
public:
    AttributeProjection(std::string subject = {});
 
    [[nodiscard]] Result<void> bindOwner(ecs::EntityHandle owner);
 
    [[nodiscard]] const ecs::EntityHandle& owner() const noexcept { return owner_; }
 
    [[nodiscard]] Revision revision() const noexcept { return revision_; }
 
    [[nodiscard]] bool isStale() const noexcept;
 
    [[nodiscard]] bool initialized() const noexcept { return initialized_; }
 
    [[nodiscard]] Result<void> initialize(std::span<const AttributeSnapshotBase> values);
 
    [[nodiscard]] Result<void> setBase(std::string_view attribute, double value);
 
    [[nodiscard]] Result<void> modifyBase(std::string_view attribute, double delta);
 
    [[nodiscard]] Result<double> getFinal(std::string_view attribute, double fallback = 0.0) const;
 
    [[nodiscard]] bool has(std::string_view attribute) const;
 
    [[nodiscard]] Result<ModifierId> addModifier(AttributeModifier modifier);
 
    [[nodiscard]] int modifierCount() const noexcept { return values_.modifierCount(); }
 
    [[nodiscard]] const AttributeModifier* modifierAt(int index) const { return values_.modifierAt(index); }
 
    [[nodiscard]] Result<AttributeProjectionSnapshot> snapshot(std::span<const std::string_view> attributes) const;
 
    [[nodiscard]] Result<void> restore(const AttributeProjectionSnapshot& snapshot, Revision expectedRevision);
 
private:
    [[nodiscard]] Result<void> advanceRevision();
    [[nodiscard]] bool         ownsSameLiveEntity(ecs::EntityHandle owner) const noexcept;
 
    AttributeSet      values_;
    ecs::EntityHandle owner_{};
    Revision          revision_    = Revision::zero();
    bool              initialized_ = false;
};
 
namespace source {
inline constexpr std::string_view definition = "definition";
inline constexpr std::string_view runtime    = "runtime";
inline constexpr std::string_view effect     = "effect";
inline constexpr std::string_view equipment  = "equipment";
}  // namespace source
 
namespace priority {
inline constexpr ModifierPriority definition = 0;
inline constexpr ModifierPriority runtime    = 100;
inline constexpr ModifierPriority effect     = 200;
inline constexpr ModifierPriority equipment  = 300;
}  // namespace priority
 
}  // namespace eve::attributes