source-engine/game/shared/tf2base/tf_weapon_knife.cpp

//====== Copyright © 1996-2005, Valve Corporation, All rights reserved. =======
//
// Purpose: Weapon Knife.
//
//=============================================================================
#include "cbase.h"
#include "tf_gamerules.h"
#include "tf_weapon_knife.h"
#include "decals.h"

// Client specific.
#ifdef CLIENT_DLL
#include "c_tf_player.h"
// Server specific.
#else
#include "tf_player.h"
#include "tf_gamestats.h"
#endif

//=============================================================================
//
// Weapon Knife tables.
//
IMPLEMENT_NETWORKCLASS_ALIASED( TFKnife, DT_TFWeaponKnife )

BEGIN_NETWORK_TABLE( CTFKnife, DT_TFWeaponKnife )
END_NETWORK_TABLE()

BEGIN_PREDICTION_DATA( CTFKnife )
END_PREDICTION_DATA()

LINK_ENTITY_TO_CLASS( tf_weapon_knife, CTFKnife );
PRECACHE_WEAPON_REGISTER( tf_weapon_knife );

//=============================================================================
//
// Weapon Knife functions.
//

//-----------------------------------------------------------------------------
// Purpose:
//-----------------------------------------------------------------------------
CTFKnife::CTFKnife()
{
}

//-----------------------------------------------------------------------------
// Purpose: Set stealth attack bool
//-----------------------------------------------------------------------------
void CTFKnife::PrimaryAttack( void )
{
	CTFPlayer *pPlayer = ToTFPlayer( GetPlayerOwner() );

	if ( !CanAttack() )
		return;

	// Set the weapon usage mode - primary, secondary.
	m_iWeaponMode = TF_WEAPON_PRIMARY_MODE;

	trace_t trace;
	if ( DoSwingTrace( trace ) == true )
	{
		// we will hit something with the attack
		if( trace.m_pEnt && trace.m_pEnt->IsPlayer() )
		{
			CTFPlayer *pTarget = ToTFPlayer( trace.m_pEnt );

			if ( pTarget && pTarget->GetTeamNumber() != pPlayer->GetTeamNumber() )
			{
				// Deal extra damage to players when stabbing them from behind
				if ( IsBehindTarget( trace.m_pEnt ) )
				{
					// this will be a backstab, do the strong anim
					m_iWeaponMode = TF_WEAPON_SECONDARY_MODE;

					// store the victim to compare when we do the damage
					m_hBackstabVictim = trace.m_pEnt;
				}
			}
		}
	}

#ifndef CLIENT_DLL
	pPlayer->RemoveInvisibility();
	pPlayer->RemoveDisguise();
#endif

	// Swing the weapon.
	Swing( pPlayer );

#if !defined( CLIENT_DLL ) 
	pPlayer->SpeakWeaponFire();
	CTF_GameStats.Event_PlayerFiredWeapon( pPlayer, IsCurrentAttackACritical() );
#endif
}

//-----------------------------------------------------------------------------
// Purpose: Do backstab damage
//-----------------------------------------------------------------------------
float CTFKnife::GetMeleeDamage( CBaseEntity *pTarget, int &iCustomDamage )
{
	float flBaseDamage = BaseClass::GetMeleeDamage( pTarget, iCustomDamage );

	if ( pTarget->IsPlayer() )
	{
		// This counts as a backstab if:
		// a ) we are behind the target player
		// or b) we were behind this target player when we started the stab
		if ( IsBehindTarget( pTarget ) ||
			( m_iWeaponMode == TF_WEAPON_SECONDARY_MODE && m_hBackstabVictim.Get() == pTarget ) )
		{
			// this will be a backstab, do the strong anim.
			// Do twice the target's health so that random modification will still kill him.
			flBaseDamage = pTarget->GetHealth() * 2;

			// Declare a backstab.
			iCustomDamage = TF_DMG_CUSTOM_BACKSTAB;
		}
		else
		{
			m_bCurrentAttackIsCrit = false;	// don't do a crit if we failed the above checks.
		}
	}

	return flBaseDamage;
}


//-----------------------------------------------------------------------------
// Purpose:
//-----------------------------------------------------------------------------
bool CTFKnife::IsBehindTarget( CBaseEntity *pTarget )
{
	Assert( pTarget );

	// Get the forward view vector of the target, ignore Z
	Vector vecVictimForward;
	AngleVectors( pTarget->EyeAngles(), &vecVictimForward, NULL, NULL );
	vecVictimForward.z = 0.0f;
	vecVictimForward.NormalizeInPlace();

	// Get a vector from my origin to my targets origin
	Vector vecToTarget;
	vecToTarget = pTarget->WorldSpaceCenter() - GetOwner()->WorldSpaceCenter();
	vecToTarget.z = 0.0f;
	vecToTarget.NormalizeInPlace();

	float flDot = DotProduct( vecVictimForward, vecToTarget );

	return ( flDot > -0.1 );
}

//-----------------------------------------------------------------------------
// Purpose: 
//-----------------------------------------------------------------------------
bool CTFKnife::CalcIsAttackCriticalHelper( void )
{
	// Always crit from behind, never from front
	return ( m_iWeaponMode == TF_WEAPON_SECONDARY_MODE );
}

//-----------------------------------------------------------------------------
// Purpose: Allow melee weapons to send different anim events
// Input  :  - 
//-----------------------------------------------------------------------------
void CTFKnife::SendPlayerAnimEvent( CTFPlayer *pPlayer )
{
	if ( m_iWeaponMode == TF_WEAPON_SECONDARY_MODE )
	{
		pPlayer->DoAnimationEvent( PLAYERANIMEVENT_CUSTOM_GESTURE, ACT_MP_ATTACK_STAND_SECONDARYFIRE );
	}
	else
	{
		pPlayer->DoAnimationEvent( PLAYERANIMEVENT_ATTACK_PRIMARY );
	}
}