ddnet/src/game/server/entities/dragger.cpp

/* (c) Shereef Marzouk. See "licence DDRace.txt" and the readme.txt in the root of the distribution for more information. */
#include <engine/config.h>
#include <engine/server.h>
#include <engine/shared/config.h>
#include <game/generated/protocol.h>
#include <game/server/gamecontext.h>
#include <game/server/gamemodes/DDRace.h>
#include <game/server/player.h>
#include <game/server/teams.h>
#include <game/version.h>

#include "character.h"
#include "dragger.h"
#include "dragger_beam.h"

CDragger::CDragger(CGameWorld *pGameWorld, vec2 Pos, float Strength, bool IgnoreWalls, int Layer, int Number) :
	CEntity(pGameWorld, CGameWorld::ENTTYPE_LASER)
{
	m_Layer = Layer;
	m_Number = Number;
	m_Pos = Pos;
	m_Strength = Strength;
	m_EvalTick = Server()->Tick();
	m_IgnoreWalls = IgnoreWalls;

	mem_zero(m_apDraggerBeam, sizeof(m_apDraggerBeam));
	GameWorld()->InsertEntity(this);
}

void CDragger::Tick()
{
	if(Server()->Tick() % int(Server()->TickSpeed() * 0.15f) == 0)
	{
		int Flags;
		m_EvalTick = Server()->Tick();
		int index = GameServer()->Collision()->IsMover(m_Pos.x, m_Pos.y, &Flags);
		if(index)
		{
			m_Core = GameServer()->Collision()->CpSpeed(index, Flags);
		}
		m_Pos += m_Core;

		// Adopt the new position for all outgoing laser beams
		for(auto &DraggerBeam : m_apDraggerBeam)
		{
			if(DraggerBeam != nullptr)
			{
				DraggerBeam->SetPos(m_Pos);
			}
		}

		LookForPlayersToDrag();
	}
}

void CDragger::LookForPlayersToDrag()
{
	// Create a list of players who are in the range of the dragger.
	CCharacter *pPlayersInRange[MAX_CLIENTS];
	mem_zero(pPlayersInRange, sizeof(pPlayersInRange));

	int NumPlayersInRange = GameServer()->m_World.FindEntities(m_Pos, g_Config.m_SvDraggerRange,
		(CEntity **)pPlayersInRange, MAX_CLIENTS, CGameWorld::ENTTYPE_CHARACTER);

	// The closest player (within range) in a team is selected as the target
	int TargetIdInTeam[MAX_CLIENTS];
	bool IsTarget[MAX_CLIENTS];
	int MinLenInTeam[MAX_CLIENTS];
	mem_zero(MinLenInTeam, sizeof(MinLenInTeam));
	mem_zero(IsTarget, sizeof(IsTarget));
	for(int &TargetId : TargetIdInTeam)
	{
		TargetId = -1;
	}

	for(int i = 0; i < NumPlayersInRange; i++)
	{
		CCharacter *pTarget = pPlayersInRange[i];
		// Do not create a dragger beam for super player
		if(pTarget->Team() == TEAM_SUPER)
		{
			continue;
		}
		// If the Dragger is disabled for the target's team, no dragger beam will be generated.
		if(m_Layer == LAYER_SWITCH && m_Number > 0 && !GameServer()->Collision()->m_pSwitchers[m_Number].m_Status[pTarget->Team()])
		{
			continue;
		}

		// Dragger beams can be created only for reachable alive players
		int IsReachable =
			m_IgnoreWalls ?
				!GameServer()->Collision()->IntersectNoLaserNW(m_Pos, pTarget->m_Pos, 0, 0) :
				!GameServer()->Collision()->IntersectNoLaser(m_Pos, pTarget->m_Pos, 0, 0);
		if(IsReachable && pTarget->IsAlive())
		{
			// Solo players are dragged independently from the rest of the team
			if(pTarget->Teams()->m_Core.GetSolo(pTarget->GetPlayer()->GetCID()))
			{
				IsTarget[pTarget->GetPlayer()->GetCID()] = true;
			}
			else
			{
				int Len = length(pTarget->m_Pos - m_Pos);
				if(MinLenInTeam[pTarget->Team()] == 0 || MinLenInTeam[pTarget->Team()] > Len)
				{
					MinLenInTeam[pTarget->Team()] = Len;
					TargetIdInTeam[pTarget->Team()] = pTarget->GetPlayer()->GetCID();
				}
			}
		}
	}

	// Set the closest player for each team as a target
	for(int &TargetId : TargetIdInTeam)
	{
		if(TargetId != -1)
		{
			IsTarget[TargetId] = true;
		}
	}

	for(int i = 0; i < MAX_CLIENTS; i++)
	{
		// Create Dragger Beams which have not been created yet
		if(IsTarget[i] && m_apDraggerBeam[i] == nullptr)
		{
			m_apDraggerBeam[i] = new CDraggerBeam(&GameServer()->m_World, this, m_Pos, m_Strength, m_IgnoreWalls, i);
		}
		// Remove dragger beams that have not yet been deleted
		else if(!IsTarget[i] && m_apDraggerBeam[i] != nullptr)
		{
			m_apDraggerBeam[i]->Reset();
		}
	}
}

void CDragger::RemoveDraggerBeam(int ClientID)
{
	m_apDraggerBeam[ClientID] = nullptr;
}

void CDragger::Reset()
{
	m_MarkedForDestroy = true;
}

void CDragger::Snap(int SnappingClient)
{
	// Only players with the dragger in their field of view or who want to see everything will receive the snap
	if(NetworkClipped(SnappingClient))
		return;

	// Send the dragger in its resting position if the player would not otherwise see a dragger beam
	for(int i = 0; i < MAX_CLIENTS; i++)
	{
		if(m_apDraggerBeam[i] != nullptr)
		{
			CCharacter *pChar = GameServer()->GetPlayerChar(i);
			if(pChar && pChar->CanSnapCharacter(SnappingClient))
			{
				return;
			}
		}
	}

	int SnappingClientVersion = SnappingClient != SERVER_DEMO_CLIENT ?
					    GameServer()->GetClientVersion(SnappingClient) :
					    CLIENT_VERSIONNR;

	CNetObj_EntityEx *pEntData = 0;
	if(SnappingClientVersion >= VERSION_DDNET_SWITCH)
	{
		pEntData = static_cast<CNetObj_EntityEx *>(Server()->SnapNewItem(NETOBJTYPE_ENTITYEX, GetID(),
			sizeof(CNetObj_EntityEx)));
		if(pEntData)
		{
			pEntData->m_SwitchNumber = m_Number;
			pEntData->m_Layer = m_Layer;
			pEntData->m_EntityClass = clamp(ENTITYCLASS_DRAGGER_WEAK + round_to_int(m_Strength) - 1,
				(int)ENTITYCLASS_DRAGGER_WEAK, (int)ENTITYCLASS_DRAGGER_STRONG);
		}
	}

	if(SnappingClientVersion < VERSION_DDNET_SWITCH)
	{
		// Emulate turned off blinking dragger for old clients
		CCharacter *pChar = GameServer()->GetPlayerChar(SnappingClient);
		if(SnappingClient != SERVER_DEMO_CLIENT && (GameServer()->m_apPlayers[SnappingClient]->GetTeam() == TEAM_SPECTATORS || GameServer()->m_apPlayers[SnappingClient]->IsPaused()) &&
			GameServer()->m_apPlayers[SnappingClient]->m_SpectatorID != SPEC_FREEVIEW)
			pChar = GameServer()->GetPlayerChar(GameServer()->m_apPlayers[SnappingClient]->m_SpectatorID);

		int Tick = (Server()->Tick() % Server()->TickSpeed()) % 11;
		if(pChar && m_Layer == LAYER_SWITCH && m_Number && !GameServer()->Collision()->m_pSwitchers[m_Number].m_Status[pChar->Team()] && (!Tick))
			return;
	}

	CNetObj_Laser *obj = static_cast<CNetObj_Laser *>(Server()->SnapNewItem(
		NETOBJTYPE_LASER, GetID(), sizeof(CNetObj_Laser)));

	if(!obj)
		return;

	obj->m_X = (int)m_Pos.x;
	obj->m_Y = (int)m_Pos.y;
	obj->m_FromX = (int)m_Pos.x;
	obj->m_FromY = (int)m_Pos.y;

	if(pEntData)
	{
		obj->m_StartTick = 0;
	}
	else
	{
		int StartTick = m_EvalTick;
		if(StartTick < Server()->Tick() - 4)
			StartTick = Server()->Tick() - 4;
		else if(StartTick > Server()->Tick())
			StartTick = Server()->Tick();
		obj->m_StartTick = StartTick;
	}
}