Peacekeeper

#include "ScriptPCH.h"

typedef struct {float x, y;} Point;

// This is a list of X, Y coordinates that you want to make your "safe area"
// The first and last points MUST be the same for this to work
static const Point V[] = { {4513.935f, -4256.359f}, {4510.568f, -4236.598f}, {4490.970f, -4249.030f}, {4489.567f, -4194.844f}, {4513.935f, -4256.359f} };
// Set n to the number of elements in V - 1
// Since there are a total of 5 points, n is 4
static const int n = 4;

class npc_peacekeeper : public CreatureScript
{
public:
    npc_peacekeeper() : CreatureScript("npc_peacekeeper") {}

    CreatureAI* GetAI(Creature* c) const
    {
        return new npc_peacekeeperAI(c);
    }

    struct npc_peacekeeperAI : public ScriptedAI
    {
        npc_peacekeeperAI(Creature* c) : ScriptedAI(c) {}

            int isLeft(Point P0, Point P1, Point P2)
            {
                return ( (P1.x - P0.x) * (P2.y - P0.y)
                        - (P2.x - P0.x) * (P1.y - P0.y) );
            }

            // Checks if a Point is inside the predefined area
            bool IsInArea(Point P)
            {
                int wn = 0;

                for (int i=0; i < n; i++)
            {
                        if (V[i].y <= P.y)
                {
                            if (V[i + 1].y > P.y)
                                if (isLeft(V[i], V[i+1], P) > 0)
                                    ++wn;
                        }
                        else
                {
                            if (V[i + 1].y <= P.y)
                                if (isLeft(V[i], V[i+1], P) < 0)
                                    --wn;
                        }
                }
                return wn != 0;
            }

            void Reset()
            {
                // Only run the check every 1 second rather than every update
                // Not sure how intensive this algorithm is, but it's better to be safe
                timer = 1000;
            }

        void UpdateAI(uint32 diff)
        {
                if (timer <= diff)
                {
                        Map::PlayerList const& Players = me->GetMap()->GetPlayers();
                        for (Map::PlayerList::const_iterator itr = Players.begin(); itr != Players.end(); ++itr)
                        {
                            if (Player* player = itr->GetSource())
                            {
                                if (player->GetAreaId() != me->GetAreaId())
                                        continue;
                                Point p = { player->GetPositionX(), player->GetPositionY() };
                                if (IsInArea(p))
                                        player->SetPvP(false);
                                else
                                        player->SetPvP(true);
                            }
                    }
                        timer = 1000;
                } else timer -= diff;
        }

            uint32 timer;
    };
};

void AddSC_npc_peacekeeper()
{
    new npc_peacekeeper();
}