OpenMW/apps/openmw/mwmechanics/aifollow.hpp

#ifndef GAME_MWMECHANICS_AIFOLLOW_H
#define GAME_MWMECHANICS_AIFOLLOW_H

#include "aitemporarybase.hpp"
#include "typedaipackage.hpp"

#include <string>
#include <string_view>

#include <components/esm/defs.hpp>

#include "../mwworld/ptr.hpp"

namespace ESM::AiSequence
{
    struct AiFollow;
}

namespace MWMechanics
{
    struct AiFollowStorage : AiTemporaryBase
    {
        float mTimer;
        bool mMoving;
        float mTargetAngleRadians;
        bool mTurnActorToTarget;

        AiFollowStorage()
            : mTimer(0.f)
            , mMoving(false)
            , mTargetAngleRadians(0.f)
            , mTurnActorToTarget(false)
        {
        }
    };

    /// \brief AiPackage for an actor to follow another actor/the PC
    /** The AI will follow the target until a condition (time, or position) are set. Both can be disabled to cause the
     *actor to follow the other indefinitely
     **/
    class AiFollow final : public TypedAiPackage<AiFollow>
    {
    public:
        /// Follow Actor for duration or until you arrive at a world position
        AiFollow(const ESM::RefId& actorId, float duration, float x, float y, float z, bool repeat);
        /// Follow Actor for duration or until you arrive at a position in a cell
        AiFollow(
            const ESM::RefId& actorId, std::string_view cellId, float duration, float x, float y, float z, bool repeat);
        /// Follow Actor indefinitely
        AiFollow(const MWWorld::Ptr& actor, bool commanded = false);

        AiFollow(const ESM::AiSequence::AiFollow* follow);

        bool execute(const MWWorld::Ptr& actor, CharacterController& characterController, AiState& state,
            float duration) override;

        static constexpr AiPackageTypeId getTypeId() { return AiPackageTypeId::Follow; }

        static constexpr Options makeDefaultOptions()
        {
            AiPackage::Options options;
            options.mUseVariableSpeed = true;
            options.mSideWithTarget = true;
            options.mFollowTargetThroughDoors = true;
            return options;
        }

        /// Returns the actor being followed
        ESM::RefId getFollowedActor();

        void writeState(ESM::AiSequence::AiSequence& sequence) const override;

        bool isCommanded() const;

        int getFollowIndex() const;

        void fastForward(const MWWorld::Ptr& actor, AiState& state) override;

        osg::Vec3f getDestination() const override
        {
            MWWorld::Ptr target = getTarget();
            if (target.isEmpty())
                return osg::Vec3f(0, 0, 0);

            return target.getRefData().getPosition().asVec3();
        }

    private:
        /// This will make the actor always follow.
        /** Thus ignoring mDuration and mX,mY,mZ (used for summoned creatures). **/
        const bool mAlwaysFollow;
        const float mDuration; // Hours
        float mRemainingDuration; // Hours
        const float mX;
        const float mY;
        const float mZ;
        const std::string mCellId;
        bool mActive; // have we spotted the target?
        const int mFollowIndex;

        static int mFollowIndexCounter;
    };
}
#endif