source-engine/game/server/NextBot/Path/NextBotChasePath.h

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// NextBotChasePath.h
// Maintain and follow a "chase path" to a selected Actor
// Author: Michael Booth, September 2006
//========= Copyright Valve Corporation, All rights reserved. ============//
#ifndef _NEXT_BOT_CHASE_PATH_
#define _NEXT_BOT_CHASE_PATH_
#include "nav.h"
#include "NextBotInterface.h"
#include "NextBotLocomotionInterface.h"
#include "NextBotChasePath.h"
#include "NextBotUtil.h"
#include "NextBotPathFollow.h"
#include "tier0/vprof.h"
//----------------------------------------------------------------------------------------------
/**
* A ChasePath extends a PathFollower to periodically recompute a path to a chase
* subject, and to move along the path towards that subject.
*/
class ChasePath : public PathFollower
{
public:
enum SubjectChaseType
{
LEAD_SUBJECT,
DONT_LEAD_SUBJECT
};
ChasePath( SubjectChaseType chaseHow = DONT_LEAD_SUBJECT );
virtual ~ChasePath() { }
virtual void Update( INextBot *bot, CBaseEntity *subject, const IPathCost &cost, Vector *pPredictedSubjectPos = NULL ); // update path to chase target and move bot along path
virtual float GetLeadRadius( void ) const; // range where movement leading begins - beyond this just head right for the subject
virtual float GetMaxPathLength( void ) const; // return maximum path length
virtual Vector PredictSubjectPosition( INextBot *bot, CBaseEntity *subject ) const; // try to cutoff our chase subject, knowing our relative positions and velocities
virtual bool IsRepathNeeded( INextBot *bot, CBaseEntity *subject ) const; // return true if situation has changed enough to warrant recomputing the current path
virtual float GetLifetime( void ) const; // Return duration this path is valid. Path will become invalid at its earliest opportunity once this duration elapses. Zero = infinite lifetime
virtual void Invalidate( void ); // (EXTEND) cause the path to become invalid
private:
void RefreshPath( INextBot *bot, CBaseEntity *subject, const IPathCost &cost, Vector *pPredictedSubjectPos );
CountdownTimer m_failTimer; // throttle re-pathing if last path attempt failed
CountdownTimer m_throttleTimer; // require a minimum time between re-paths
CountdownTimer m_lifetimeTimer;
EHANDLE m_lastPathSubject; // the subject used to compute the current/last path
SubjectChaseType m_chaseHow;
};
inline ChasePath::ChasePath( SubjectChaseType chaseHow )
{
m_failTimer.Invalidate();
m_throttleTimer.Invalidate();
m_lifetimeTimer.Invalidate();
m_lastPathSubject = NULL;
m_chaseHow = chaseHow;
}
inline float ChasePath::GetLeadRadius( void ) const
{
return 500.0f; // 1000.0f;
}
inline float ChasePath::GetMaxPathLength( void ) const
{
// no limit
return 0.0f;
}
inline float ChasePath::GetLifetime( void ) const
{
// infinite duration
return 0.0f;
}
inline void ChasePath::Invalidate( void )
{
// path is gone, repath at earliest opportunity
m_throttleTimer.Invalidate();
m_lifetimeTimer.Invalidate();
// extend
PathFollower::Invalidate();
}
//----------------------------------------------------------------------------------------------
/**
* Maintain a path to our chase subject and move along that path
*/
inline void ChasePath::Update( INextBot *bot, CBaseEntity *subject, const IPathCost &cost, Vector *pPredictedSubjectPos )
{
VPROF_BUDGET( "ChasePath::Update", "NextBot" );
// maintain the path to the subject
RefreshPath( bot, subject, cost, pPredictedSubjectPos );
// move along the path towards the subject
PathFollower::Update( bot );
}
//----------------------------------------------------------------------------------------------
/**
* Return true if situation has changed enough to warrant recomputing the current path
*/
inline bool ChasePath::IsRepathNeeded( INextBot *bot, CBaseEntity *subject ) const
{
// the closer we get, the more accurate our path needs to be
Vector to = subject->GetAbsOrigin() - bot->GetPosition();
const float minTolerance = 0.0f; // 25.0f;
const float toleranceRate = 0.33f; // 1.0f; // 0.15f;
float tolerance = minTolerance + toleranceRate * to.Length();
return ( subject->GetAbsOrigin() - GetEndPosition() ).IsLengthGreaterThan( tolerance );
}
//----------------------------------------------------------------------------------------------
/**
* Periodically rebuild the path to our victim
*/
inline void ChasePath::RefreshPath( INextBot *bot, CBaseEntity *subject, const IPathCost &cost, Vector *pPredictedSubjectPos )
{
VPROF_BUDGET( "ChasePath::RefreshPath", "NextBot" );
ILocomotion *mover = bot->GetLocomotionInterface();
// don't change our path if we're on a ladder
if ( IsValid() && mover->IsUsingLadder() )
{
if ( bot->IsDebugging( NEXTBOT_PATH ) )
{
DevMsg( "%3.2f: bot(#%d) ChasePath::RefreshPath failed. Bot is on a ladder.\n", gpGlobals->curtime, bot->GetEntity()->entindex() );
}
// don't allow repath until a moment AFTER we have left the ladder
m_throttleTimer.Start( 1.0f );
return;
}
if ( subject == NULL )
{
if ( bot->IsDebugging( NEXTBOT_PATH ) )
{
DevMsg( "%3.2f: bot(#%d) CasePath::RefreshPath failed. No subject.\n", gpGlobals->curtime, bot->GetEntity()->entindex() );
}
return;
}
if ( !m_failTimer.IsElapsed() )
{
// if ( bot->IsDebugging( NEXTBOT_PATH ) )
// {
// DevMsg( "%3.2f: bot(#%d) ChasePath::RefreshPath failed. Fail timer not elapsed.\n", gpGlobals->curtime, bot->GetEntity()->entindex() );
// }
return;
}
// if our path subject changed, repath immediately
if ( subject != m_lastPathSubject )
{
if ( bot->IsDebugging( NEXTBOT_PATH ) )
{
DevMsg( "%3.2f: bot(#%d) Chase path subject changed (from %p to %p).\n", gpGlobals->curtime, bot->GetEntity()->entindex(), m_lastPathSubject.Get(), subject );
}
Invalidate();
// new subject, fresh attempt
m_failTimer.Invalidate();
}
if ( IsValid() && !m_throttleTimer.IsElapsed() )
{
// require a minimum time between repaths, as long as we have a path to follow
// if ( bot->IsDebugging( NEXTBOT_PATH ) )
// {
// DevMsg( "%3.2f: bot(#%d) ChasePath::RefreshPath failed. Rate throttled.\n", gpGlobals->curtime, bot->GetEntity()->entindex() );
// }
return;
}
if ( IsValid() && m_lifetimeTimer.HasStarted() && m_lifetimeTimer.IsElapsed() )
{
// this path's lifetime has elapsed
Invalidate();
}
if ( !IsValid() || IsRepathNeeded( bot, subject ) )
{
// the situation has changed - try a new path
bool isPath;
Vector pathTarget = subject->GetAbsOrigin();
if ( m_chaseHow == LEAD_SUBJECT )
{
pathTarget = pPredictedSubjectPos ? *pPredictedSubjectPos : PredictSubjectPosition( bot, subject );
isPath = Compute( bot, pathTarget, cost, GetMaxPathLength() );
}
else if ( subject->MyCombatCharacterPointer() && subject->MyCombatCharacterPointer()->GetLastKnownArea() )
{
isPath = Compute( bot, subject->MyCombatCharacterPointer(), cost, GetMaxPathLength() );
}
else
{
isPath = Compute( bot, pathTarget, cost, GetMaxPathLength() );
}
if ( isPath )
{
if ( bot->IsDebugging( NEXTBOT_PATH ) )
{
//const float size = 20.0f;
//NDebugOverlay::VertArrow( bot->GetPosition() + Vector( 0, 0, size ), bot->GetPosition(), size, 255, RandomInt( 0, 200 ), 255, 255, true, 30.0f );
DevMsg( "%3.2f: bot(#%d) REPATH\n", gpGlobals->curtime, bot->GetEntity()->entindex() );
}
m_lastPathSubject = subject;
const float minRepathInterval = 0.5f;
m_throttleTimer.Start( minRepathInterval );
// track the lifetime of this new path
float lifetime = GetLifetime();
if ( lifetime > 0.0f )
{
m_lifetimeTimer.Start( lifetime );
}
else
{
m_lifetimeTimer.Invalidate();
}
}
else
{
// can't reach subject - throttle retry based on range to subject
m_failTimer.Start( 0.005f * ( bot->GetRangeTo( subject ) ) );
// allow bot to react to path failure
bot->OnMoveToFailure( this, FAIL_NO_PATH_EXISTS );
if ( bot->IsDebugging( NEXTBOT_PATH ) )
{
//const float size = 20.0f;
const float dT = 90.0f;
int c = RandomInt( 0, 100 );
//NDebugOverlay::VertArrow( bot->GetPosition() + Vector( 0, 0, size ), bot->GetPosition(), size, 255, c, c, 255, true, dT );
NDebugOverlay::HorzArrow( bot->GetPosition(), pathTarget, 5.0f, 255, c, c, 255, true, dT );
DevMsg( "%3.2f: bot(#%d) REPATH FAILED\n", gpGlobals->curtime, bot->GetEntity()->entindex() );
}
Invalidate();
}
}
}
//----------------------------------------------------------------------------------------------------------------------------------------------
//----------------------------------------------------------------------------------------------------------------------------------------------
/**
* Directly beeline toward victim if we have a clear shot, otherwise pathfind.
*/
class DirectChasePath : public ChasePath
{
public:
DirectChasePath( ChasePath::SubjectChaseType chaseHow = ChasePath::DONT_LEAD_SUBJECT ) : ChasePath( chaseHow )
{
}
//-------------------------------------------------------------------------------------------------------
virtual void Update( INextBot *me, CBaseEntity *victim, const IPathCost &pathCost, Vector *pPredictedSubjectPos = NULL ) // update path to chase target and move bot along path
{
Assert( !pPredictedSubjectPos );
bool bComputedPredictedPosition;
Vector vecPredictedPosition;
if ( !DirectChase( &bComputedPredictedPosition, &vecPredictedPosition, me, victim ) )
{
// path around obstacles to reach our victim
ChasePath::Update( me, victim, pathCost, bComputedPredictedPosition ? &vecPredictedPosition : NULL );
}
NotifyVictim( me, victim );
}
//-------------------------------------------------------------------------------------------------------
bool DirectChase( bool *pPredictedPositionComputed, Vector *pPredictedPos, INextBot *me, CBaseEntity *victim ) // if there is nothing between us and our victim, run directly at them
{
*pPredictedPositionComputed = false;
ILocomotion *mover = me->GetLocomotionInterface();
if ( me->IsImmobile() || mover->IsScrambling() )
{
return false;
}
if ( IsDiscontinuityAhead( me, CLIMB_UP ) )
{
return false;
}
if ( IsDiscontinuityAhead( me, JUMP_OVER_GAP ) )
{
return false;
}
Vector leadVictimPos = PredictSubjectPosition( me, victim );
// Don't want to have to compute the predicted position twice.
*pPredictedPositionComputed = true;
*pPredictedPos = leadVictimPos;
if ( !mover->IsPotentiallyTraversable( mover->GetFeet(), leadVictimPos ) )
{
return false;
}
// the way is clear - move directly towards our victim
mover->FaceTowards( leadVictimPos );
mover->Approach( leadVictimPos );
me->GetBodyInterface()->AimHeadTowards( victim );
// old path is no longer useful since we've moved off of it
Invalidate();
return true;
}
//-------------------------------------------------------------------------------------------------------
virtual bool IsRepathNeeded( INextBot *bot, CBaseEntity *subject ) const // return true if situation has changed enough to warrant recomputing the current path
{
if ( ChasePath::IsRepathNeeded( bot, subject ) )
{
return true;
}
return bot->GetLocomotionInterface()->IsStuck() && bot->GetLocomotionInterface()->GetStuckDuration() > 2.0f;
}
//-------------------------------------------------------------------------------------------------------
/**
* Determine exactly where the path goes between the given two areas
* on the path. Return this point in 'crossPos'.
*/
virtual void ComputeAreaCrossing( INextBot *bot, const CNavArea *from, const Vector &fromPos, const CNavArea *to, NavDirType dir, Vector *crossPos ) const
{
Vector center;
float halfWidth;
from->ComputePortal( to, dir, &center, &halfWidth );
*crossPos = center;
}
void NotifyVictim( INextBot *me, CBaseEntity *victim );
};
#endif // _NEXT_BOT_CHASE_PATH_