Simulated Bullets

Preface

Basically, with simulated bullets, the aspects of physics are going to tried to be captured by simulating them in batch simulation code. So far the code is all server-side and is later expected to be client-side simulated with similar code. Bullet simulation using individual entities is not the way to go because they can fill up the entity list and are just unconventional.

Note:This code is a work in progress. Feel free to make helpful changes.

Alteration

The code creates two ConVars which allow the host to change the penetration allowed and the maximum speed at which a bullet is removed.

Body

This code is WIP by ts2do

game_shared

bullet_manager.h

#include "ammodef.h"
#define BUTTER_MODE -1
#define ONE_HIT_MODE -2

#ifdef CLIENT_DLL//-----------------------
class C_BulletManager;
extern C_BulletManager *g_pBulletManager;
#define CBulletManager C_BulletManager
#define CSimulatedBullet C_SimulatedBullet
#else//-----------------------------------
class CBulletManager;
extern CBulletManager *g_pBulletManager;
#endif//----------------------------------

inline CBulletManager *BulletManager()
{
	return g_pBulletManager;
}

extern ConVar g_debug_bullets;
class CSimulatedBullet
{
public:
	CSimulatedBullet();
	CSimulatedBullet( CBaseEntity *pAttacker, CBaseEntity *pAdditionalIgnoreEnt,
						int ammoType, int nFlags, Vector &vecDirShooting,
						Vector &vecOrigin, int damageType
#ifndef CLIENT_DLL
						, CBaseEntity *pCaller, int iDamage, float flLagCompensation
#endif
						);
	~CSimulatedBullet();
	inline float BulletSpeedRatio(void)
	{
		return m_flBulletSpeed/m_flInitialBulletSpeed;
	}
	inline bool IsInWorld(void) const
	{
		if (m_vecOrigin.x >= MAX_COORD_INTEGER) return false;
		if (m_vecOrigin.y >= MAX_COORD_INTEGER) return false;
		if (m_vecOrigin.z >= MAX_COORD_INTEGER) return false;
		if (m_vecOrigin.x <= MIN_COORD_INTEGER) return false;
		if (m_vecOrigin.y <= MIN_COORD_INTEGER) return false;
		if (m_vecOrigin.z <= MIN_COORD_INTEGER) return false;
		return true;
	}
	bool StartSolid(trace_t &ptr, Vector &vecNewRay);
	bool AllSolid(trace_t &ptr);
	bool EndSolid(trace_t &ptr);
#ifdef CLIENT_DLL
	bool SimulateBullet(void);
#else
	void EntityImpact(trace_t &ptr);
	bool SimulateBullet(float flLagCompensation=-1);
#endif
	inline int AmmoIndex(void) const
	{
		return m_iAmmoType;
	}
private:
	bool m_bWasInWater;

	CTraceFilterSkipTwoEntities *m_pTwoEnts;
	CTraceFilterSimpleList *m_pIgnoreList;//already hit
#ifndef CLIENT_DLL
	CUtlVector<CBaseEntity *> m_CompensationConsiderations;//Couldn't resist
#endif

	EHANDLE m_hCaller;

	FireBulletsFlags_t m_nFlags;

	float m_flBulletSpeed;
	float m_flEntryDensity;
	float m_flInitialBulletSpeed;

	int m_iAmmoType;
#ifndef CLIENT_DLL
	int m_iDamage;
#endif
	int m_nDamageType;

	Vector m_vecDirShooting;
	Vector m_vecOrigin;
	Vector m_vecEntryPosition;
	// Prevent copies 
private: 
	CSimulatedBullet( const CSimulatedBullet& other ); 
	CSimulatedBullet& operator=( const CSimulatedBullet& other ); 
};
class CBulletManager : public CBaseEntity
{
	DECLARE_CLASS( CBulletManager, CBaseEntity );
public:
#ifdef CLIENT_DLL
	void ClientThink(void);
#else
	void Spawn(void);
	void Think(void);
#endif
	int AddBullet(CSimulatedBullet *pBullet, float flLatency);
	int RemoveBullet(int index);
	void UpdateBulletStopSpeed(void);
	int BulletStopSpeed(void)
	{
		return m_iBulletStopSpeed;
	}
private:
	int m_iBulletStopSpeed;
	CUtlLinkedList<CSimulatedBullet*,int> m_Bullets;
};

bullet_manager.cpp

#include "cbase.h"
#include "util_shared.h"
#include "bullet_manager.h"
#include "shot_manipulator.h"
#pragma warning(disable:4800)

#ifdef CLIENT_DLL//-------------------------------------------------
#include "c_te_effect_dispatch.h"
#include "engine/ivdebugoverlay.h"
ConVar g_cl_debug_bullets( "g_cl_debug_bullets", "0", FCVAR_CHEAT );
C_BulletManager *g_pBulletManager = (C_BulletManager *)CreateEntityByName("bullet_manager");
extern void FX_PlayerTracer( Vector& start, Vector& end);
#else//-------------------------------------------------------------
#include "soundent.h"
#include "player_pickup.h"
ConVar g_debug_bullets( "g_debug_bullets", "0", FCVAR_CHEAT );
CBulletManager *g_pBulletManager;
#endif//------------------------------------------------------------

// memdbgon must be the last include file in a .cpp file!!!
#include "tier0/memdbgon.h"
static void BulletSpeedModifierCallback(ConVar *var, const char *pOldString)
{
	if(var->GetFloat()==0.0f)
		var->Revert();
}
ConVar sv_bullet_speed_modifier( "sv_bullet_speed_modifier", "700.000000", (FCVAR_ARCHIVE | FCVAR_REPLICATED),
								"Density/(This Value) * (Distance Penetrated) = (Change in Speed)",
								BulletSpeedModifierCallback );

static void BulletStopSpeedCallback(ConVar *var, const char *pOldString)
{
	float val = var->GetFloat();
	if(val==0.0f||(val<0.0f&&(val!=BUTTER_MODE||val!=ONE_HIT_MODE)))
		var->Revert();
}
ConVar sv_bullet_stop_speed( "sv_bullet_stop_speed", "40.000000", (FCVAR_ARCHIVE | FCVAR_REPLICATED),
							"Speed at which to remove the bullet from the bullet queue\n-1 is butter mode\n-2 is 1 hit mode",
							BulletStopSpeedCallback );

LINK_ENTITY_TO_CLASS( bullet_manager, CBulletManager );
#ifndef CLIENT_DLL
void CBulletManager::Spawn(void)
{
	Think();
}
#endif
CSimulatedBullet::CSimulatedBullet()
{
	m_vecOrigin.Init();
	m_vecDirShooting.Init();
	m_flInitialBulletSpeed = m_flBulletSpeed = BULLET_SPEED;
#ifndef CLIENT_DLL
	m_flLagCompensation =
#endif
	m_flEntryDensity = 0.0f;
	m_nFlags = (FireBulletsFlags_t)0;
#ifndef CLIENT_DLL
	m_iDamage = m_nDamageType =
#endif
	m_iAmmoType = 0;
}
CSimulatedBullet::CSimulatedBullet( CBaseEntity *pAttacker, CBaseEntity *pAdditionalIgnoreEnt,
									int ammoType, int nFlags, Vector &vecDirShooting,
									Vector &vecOrigin, int damageType
#ifndef CLIENT_DLL
									, CBaseEntity *pCaller, int iDamage, float flLagCompensation
#endif
									)
{
	m_nFlags = (FireBulletsFlags_t)nFlags;
	m_iAmmoType = ammoType;
	m_vecOrigin = vecOrigin;
	m_vecDirShooting = vecDirShooting;
	m_flInitialBulletSpeed = m_flBulletSpeed = GetAmmoDef()->GetAmmoOfIndex(ammoType)->flFeetPerSecond * 0.12;
	//m_flInitialBulletSpeed = m_flBulletSpeed = BULLET_SPEED;
	m_flEntryDensity = 0.0f;
#ifndef CLIENT_DLL
	m_flLagCompensation = 100*flLagCompensation;
	m_iDamage = iDamage;
	m_hCaller = pCaller;
#endif
	m_nDamageType = damageType;
	m_pIgnoreList = new CTraceFilterSimpleList(COLLISION_GROUP_NONE);
	m_pIgnoreList->AddEntityToIgnore(pAttacker);
	if(pAdditionalIgnoreEnt!=NULL)
		m_pIgnoreList->AddEntityToIgnore(pAdditionalIgnoreEnt);
	m_pTwoEnts = new CTraceFilterSkipTwoEntities(pAttacker,pAdditionalIgnoreEnt,COLLISION_GROUP_NONE);
}
CSimulatedBullet::~CSimulatedBullet()
{
	delete m_pIgnoreList;
	delete m_pTwoEnts;
}
#define REMOVE_BULLET_AND_END(x) BulletManager()->RemoveBullet(x);return
#ifdef CLIENT_DLL
void CSimulatedBullet::SimulateBullet(int index)
#else
void CSimulatedBullet::SimulateBullet(int index, float flTime/*=1.00f (1/100 sec)*/)
#endif
{
	Vector vecEntryPosition;
	Vector vecExitPosition;
	float flPenetrationDistance = 0.0f;
	trace_t trace, trace_back;
	Vector vecOldOrigin(m_vecOrigin);
	Vector vecTraceStart(m_vecOrigin);
	
	
#ifdef CLIENT_DLL
	Vector vecNewRay = m_vecDirShooting * m_flBulletSpeed;
#else
	Vector vecNewRay = m_vecDirShooting * m_flBulletSpeed * flTime;
#endif

	DevMsg("Bullet %i Speed %f\n",index,m_flBulletSpeed);
	m_vecOrigin += vecNewRay;//in/100th of a sec * 100th of a sec
	bool bInWater = UTIL_PointContents(m_vecOrigin)&MASK_SPLITAREAPORTAL;
	if(!IsInWorld())
	{
		REMOVE_BULLET_AND_END(index);
	}
#ifdef CLIENT_DLL
	FX_PlayerTracer( vecOldOrigin, m_vecOrigin );
#endif
	if(m_bWasInWater!=bInWater)
	{
#ifdef CLIENT_DLL
		//TODO: water impact effect
		//CBaseEntity::HandleShotImpactingWater
#endif //CLIENT_DLL
	}
	if(bInWater)
	{
#ifdef CLIENT_DLL
		//TODO: 1 bubble clientside
#endif //CLIENT_DLL
	}
	
#ifdef CLIENT_DLL
	if(g_cl_debug_bullets.GetBool())
	{
		debugoverlay->AddLineOverlay( vecOldOrigin, m_vecOrigin, 255, 0, 0, true, 10.0f );
	}
#else
	if(g_debug_bullets.GetBool())
	{
		NDebugOverlay::Line( vecOldOrigin, m_vecOrigin, 255, 255, 255, true, 10.0f );
	}
#endif
	m_bWasInWater = bInWater;
	float flBulletStopSpeed = sv_bullet_stop_speed.GetFloat();
	int iBulletStopSpeedCase = (int)flBulletStopSpeed;
	do
	{
		UTIL_TraceLine( vecTraceStart, m_vecOrigin, MASK_SHOT, m_pIgnoreList, &trace );
		if(!(trace.surface.flags&SURF_SKY))
		{
			if(trace.allsolid)//in solid
			{
				trace.endpos = m_vecOrigin;
				trace.fraction = 1.0f;
				switch(iBulletStopSpeedCase)
				{
					case BUTTER_MODE:
					{
						//Do nothing to bullet speed
						break;
					}
					case ONE_HIT_MODE:
					{
						REMOVE_BULLET_AND_END(index);
					}
					default:
					{
						m_flBulletSpeed -= m_flBulletSpeed * m_flEntryDensity / sv_bullet_speed_modifier.GetFloat();
						break;
					}
				}
				break;
			}
			else if(trace.startsolid)//exit solid
			{
#ifdef CLIENT_DLL
				//TODO: penetration surface impact stuff
#endif //CLIENT_DLL
				vecExitPosition = trace.fractionleftsolid * vecNewRay + vecTraceStart;
				flPenetrationDistance = vecEntryPosition.DistTo(vecExitPosition);
				switch(iBulletStopSpeedCase)
				{
					case BUTTER_MODE:
					{
						//Do nothing to bullet speed
						break;
					}
					case ONE_HIT_MODE:
					{
						REMOVE_BULLET_AND_END(index);
					}
					default:
					{
						m_flBulletSpeed -= flPenetrationDistance * m_flEntryDensity / sv_bullet_speed_modifier.GetFloat();
						break;
					}
				}
			}
			else if(trace.fraction!=1.0f)//hit solid
			{
				vecEntryPosition = trace.endpos;
#ifndef CLIENT_DLL
				int soundEntChannel = ( m_nFlags&FIRE_BULLETS_TEMPORARY_DANGER_SOUND ) ? SOUNDENT_CHANNEL_BULLET_IMPACT : SOUNDENT_CHANNEL_UNSPECIFIED;

				CSoundEnt::InsertSound( SOUND_BULLET_IMPACT, vecEntryPosition, 200, 0.5, m_hCaller, soundEntChannel );
#endif
				if(FStrEq(trace.surface.name,"tools/toolsblockbullets"))
				{
					REMOVE_BULLET_AND_END(index);
				}
#ifdef CLIENT_DLL
				CEffectData data;
				data.m_vStart = trace.startpos;
				data.m_vOrigin = trace.endpos;
				data.m_nDamageType = m_nDamageType;
				//Clientside ragdolls' locations cannot be determined by the server
				DispatchEffect( "RagdollImpact", data );
				//TODO: surface impact stuff
#endif //CLIENT_DLL
				m_flEntryDensity = physprops->GetSurfaceData(trace.surface.surfaceProps)->physics.density;
				if(trace.DidHitNonWorldEntity())
				{
					if(m_pIgnoreList->ShouldHitEntity(trace.m_pEnt,MASK_SHOT))
					{
						m_pIgnoreList->AddEntityToIgnore(trace.m_pEnt);
#ifndef CLIENT_DLL
						EntityImpact(trace.m_pEnt);
#endif
					}
				}
				if(iBulletStopSpeedCase==ONE_HIT_MODE)
				{
					REMOVE_BULLET_AND_END(index);
				}
			}
		}
		vecTraceStart = trace.endpos + m_vecDirShooting;
	}while(trace.endpos!=m_vecOrigin&&m_flBulletSpeed>flBulletStopSpeed);


	if(m_flBulletSpeed<=flBulletStopSpeed)
	{
		REMOVE_BULLET_AND_END(index);
	}
}
#ifndef CLIENT_DLL
void CSimulatedBullet::EntityImpact(CBaseEntity *pHit)
{
	//TODO: entity impact stuff
	if ( GetAmmoDef()->Flags(m_iAmmoType) & AMMO_FORCE_DROP_IF_CARRIED )
	{
		// Make sure if the player is holding this, he drops it
		Pickup_ForcePlayerToDropThisObject( pHit );		
	}
}
void CBulletManager::Think(void)
#else
void CBulletManager::ClientThink(void)
#endif
{
	for(int x=0;x<m_pBullets.Count();x++)
	{
		m_pBullets[x]->SimulateBullet(x);
	}
#ifdef CLIENT_DLL
	SetNextClientThink( gpGlobals->curtime + 0.01f );
#else
	SetNextThink( gpGlobals->curtime + 0.01f );
#endif
}
void CBulletManager::AddBullet(CSimulatedBullet *pBullet)
{
	if (pBullet->AmmoIndex() == -1)
	{
		DevMsg("ERROR: Undefined ammo type!\n");
		return;
	}
	int index = m_pBullets.AddToTail(pBullet);
	
#ifdef CLIENT_DLL
	DevMsg( "Client Bullet Created (%i)\n", index);
#else
	DevMsg( "Bullet Created (%i) LagCompensation %f\n", index, pBullet->LagCompensation() );
	if(m_pBullets[index]->LagCompensation()!=0.0f)
		m_pBullets[index]->SimulateBullet(index, pBullet->LagCompensation());
#endif
}
void CBulletManager::RemoveBullet(int index)
{
#ifdef CLIENT_DLL
	DevMsg("Client ");
#endif
	DevMsg( "Bullet Removed (%i)\n", index );
	m_pBullets.Remove(index);
}

Implementation

game_shared

gamerules.cpp

Add	#include "bullet_manager.h"
After	#include "filesystem.h"

---

Add	g_pBulletManager = (CBulletManager*)CBaseEntity::Create( "bullet_manager", vec3_origin, vec3_angle );
After	g_pPlayerResource = (CPlayerResource*)CBaseEntity::Create( "player_manager", vec3_origin, vec3_angle );

ammodef.h

Change the Ammo_t structure to the following:

struct Ammo_t 
{
	char 					*pName;
	int					nDamageType;
	int					eTracerType;
	float					physicsForceImpulse;
	float					bulletSpeed;
	int					nMinSplashSize;
	int					nMaxSplashSize;

	int					nFlags;

	// Values for player/NPC damage and carrying capability
	// If the integers are set, they override the CVars
	int					pPlrDmg;		// CVar for player damage amount
	int					pNPCDmg;		// CVar for NPC damage amount
	int					pMaxCarry;		// CVar for maximum number can carry
	const ConVar*				pPlrDmgCVar;		// CVar for player damage amount
	const ConVar*				pNPCDmgCVar;		// CVar for NPC damage amount
	const ConVar*				pMaxCarryCVar;		// CVar for maximum number can carry
};

---

Change the first two AddAmmoType function prototypes to the following:

	void				AddAmmoType(char const* name, int damageType, int tracerType,
							int plr_dmg, int npc_dmg, int carry,
							float bulletSpeed, float physicsForceImpulse,
							int nFlags, int minSplashSize = 4,
							int maxSplashSize = 8 );

	void				AddAmmoType(char const* name, int damageType, int tracerType,
							char const* plr_cvar, char const* npc_var,
							char const* carry_cvar, float bulletSpeed,
							float physicsForceImpulse, int nFlags,
							int minSplashSize = 4, int maxSplashSize = 8 );

ammodef.cpp

Add	float bulletSpeed,
Before both	float physicsForceImpulse,

---

Add	m_AmmoType[m_nAmmoIndex].bulletSpeed = bulletSpeed;
Before both	m_AmmoType[m_nAmmoIndex].physicsForceImpulse = physicsForceImpulse;

hl2mp_gamerules.cpp

Change GetAmmoDef to the following:

#define BULLET_SPEED(ftpersec) 0.12*ftpersec//inches per hundredth of a second
CAmmoDef *GetAmmoDef()
{
	static CAmmoDef def;
	static bool bInitted = false;
	
	if ( !bInitted )
	{
		bInitted = true;
		//		Name		Damage				Tracer			PlrDmg	NPCDmg	MaxCarry	Bulletspeed		Physics Force Impulse		Flags
		def.AddAmmoType("AR2",		DMG_BULLET,			TRACER_LINE_AND_WHIZ,	0,	0,	60,		BULLET_SPEED(1225),	BULLET_IMPULSE(200, 1225),	0 );
		def.AddAmmoType("AR2AltFire",	DMG_DISSOLVE,			TRACER_NONE,		0,	0,	3,		0,			0,				0 );
		def.AddAmmoType("Pistol",	DMG_BULLET,			TRACER_LINE_AND_WHIZ,	0,	0,	150,		BULLET_SPEED(1225),	BULLET_IMPULSE(200, 1225),	0 );
		def.AddAmmoType("SMG1",		DMG_BULLET,			TRACER_LINE_AND_WHIZ,	0,	0,	225,		BULLET_SPEED(1225),	BULLET_IMPULSE(200, 1225),	0 );
		def.AddAmmoType("357",		DMG_BULLET,			TRACER_LINE_AND_WHIZ,	0,	0,	12,		BULLET_SPEED(5000),	BULLET_IMPULSE(800, 5000),	0 );
		def.AddAmmoType("XBowBolt",	DMG_BULLET,			TRACER_LINE,		0,	0,	10,		BULLET_SPEED(8000),	BULLET_IMPULSE(800, 8000),	0 );
		def.AddAmmoType("Buckshot",	DMG_BULLET | DMG_BUCKSHOT,	TRACER_LINE,		0,	0,	30,		BULLET_SPEED(1200),	BULLET_IMPULSE(400, 1200),	0 );
		def.AddAmmoType("RPG_Round",	DMG_BURN,			TRACER_NONE,		0,	0,	3,		0,			0,				0 );
		def.AddAmmoType("SMG1_Grenade",	DMG_BURN,			TRACER_NONE,		0,	0,	3,		0,			0,				0 );
		def.AddAmmoType("Grenade",	DMG_BURN,			TRACER_NONE,		0,	0,	5,		0,			0,				0 );
		def.AddAmmoType("slam",		DMG_BURN,			TRACER_NONE,		0,	0,	5,		0,			0,				0 );
	}

	return &def;
}

As you can see, the bullet speed is derived from the ftpersec of the bullet impulses.

baseentity_shared.cpp

In CBaseEntity::FireBullets

TODO

dlls

player_lagcompensation.cpp

Add the following function to this file:

static int GetTargetTick(CBasePlayer *player,CUserCmd *cmd)
{
	static CBasePlayer *lastPlayer;
	static int lastTarget;
	if(player==lastPlayer)
		return lastTarget;
	// Get true latency

	// correct is the amout of time we have to correct game time
	float correct = 0.0f;

	INetChannelInfo *nci = engine->GetPlayerNetInfo( player->entindex() ); 

	if ( nci )
	{
		// add network latency
		correct+= nci->GetLatency( FLOW_OUTGOING );
	}

	// calc number of view interpolation ticks - 1
	int lerpTicks = TIME_TO_TICKS( player->m_fLerpTime );

	// add view interpolation latency see C_BaseEntity::GetInterpolationAmount()
	correct += TICKS_TO_TIME( lerpTicks );
	
	// check bouns [0,sv_maxunlag]
	correct = clamp( correct, 0.0f, sv_maxunlag.GetFloat() );

	// correct tick send by player 
	int targettick = cmd->tick_count - lerpTicks;

	// calc difference between tick send by player and our latency based tick
	float deltaTime =  correct - TICKS_TO_TIME(gpGlobals->tickcount - targettick);

	if ( fabs( deltaTime ) > 0.2f )
	{
		// difference between cmd time and latency is too big > 200ms, use time correction based on latency
		// DevMsg("StartLagCompensation: delta too big (%.3f)\n", deltaTime );
		targettick = gpGlobals->tickcount - TIME_TO_TICKS( correct );
	}
	lastPlayer = player;
	lastTarget = targettick;
	return targettick;
}

---

In CLagCompensationManager::StartLagCompensation

Replace

// Get true latency // correct is the amout of time we have to correct game time float correct = 0.0f; INetChannelInfo *nci = engine->GetPlayerNetInfo( player->entindex() ); if ( nci ) { // add network latency correct+= nci->GetLatency( FLOW_OUTGOING ); } // calc number of view interpolation ticks - 1 int lerpTicks = TIME_TO_TICKS( player->m_fLerpTime ); // add view interpolation latency see C_BaseEntity::GetInterpolationAmount() correct += TICKS_TO_TIME( lerpTicks ); // check bouns [0,sv_maxunlag] correct = clamp( correct, 0.0f, sv_maxunlag.GetFloat() ); // correct tick send by player int targettick = cmd->tick_count - lerpTicks; // calc difference between tick send by player and our latency based tick float deltaTime = correct - TICKS_TO_TIME(gpGlobals->tickcount - targettick); if ( fabs( deltaTime ) > 0.2f ) { // difference between cmd time and latency is too big > 200ms, use time correction based on latency // DevMsg("StartLagCompensation: delta too big (%.3f)\n", deltaTime ); targettick = gpGlobals->tickcount - TIME_TO_TICKS( correct ); }

With

int targettick = GetTargetTick(player);

ilagcompensationmanager.h

Add	static int GetTargetTick(CBasePlayer *player,CUserCmd *cmd);
Before	extern ILagCompensationManager *lagcompensation;

player_command.cpp

In CPlayerMove::StartCommand

Comment out

lagcompensation->StartLagCompensation( player, cmd );

hl2mp_player.cpp

The bullets will know when they're being fired so in CHL2MP_Player::WantsLagCompensationOnEntity

Comment out

if ( !( pCmd->buttons & IN_ATTACK ) && (pCmd->command_number - m_iLastWeaponFireUsercmd > 5) ) return false;

---

In CHL2MP_Player::FireBullets

Add	lagcompensation->StartLagCompensation(this, m_pCurrentCommand); modinfo.m_flLatency = TICKS_TO_TIME(GetTargetTick(this,m_pCurrentCommand));
Before	BaseClass::FireBullets( modinfo );

Add	lagcompensation->FinishLagCompensation(this);
After	BaseClass::FireBullets( modinfo );