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game/server/tf/nav_mesh/tf_path_follower.cpp

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+//========= Copyright Valve Corporation, All rights reserved. ============//
+// tf_path_follower.cpp
+// Simplified path following for TF2
+// Author: Michael Booth, November 2010
+
+#include "cbase.h"
+
+#include "NextBotManager.h"
+#include "tf_path_follower.h"
+
+// memdbgon must be the last include file in a .cpp file!!!
+#include "tier0/memdbgon.h"
+
+
+
+//--------------------------------------------------------------------------------------------------------------
+/**
+ * Constructor
+ */
+CTFPathFollower::CTFPathFollower( void )
+{
+	m_goal = NULL;
+	m_minLookAheadRange = 300.0f;
+}
+
+
+//--------------------------------------------------------------------------------------------------------------
+CTFPathFollower::~CTFPathFollower()
+{
+	// allow bots to detach pointer to me
+	CUtlVector< INextBot * > botVector;
+	TheNextBots().CollectAllBots( &botVector );
+	
+	for( int i=0; i<botVector.Count(); ++i )
+	{
+		botVector[i]->NotifyPathDestruction( this );
+	}
+}
+
+
+//--------------------------------------------------------------------------------------------------------------
+/**
+ * When the path is invalidated, the follower is also reset
+ */
+void CTFPathFollower::Invalidate( void )
+{
+	// extend
+	Path::Invalidate();
+
+	m_goal = NULL;
+	MoveCursorToStart();
+}
+
+
+//--------------------------------------------------------------------------------------------------------------
+/**
+ * Invoked when the path is (re)computed (path is valid at the time of this call)
+ */
+void CTFPathFollower::OnPathChanged( INextBot *bot, Path::ResultType result )
+{
+	// start from the beginning
+	m_goal = FirstSegment();
+	MoveCursorToStart();
+}
+
+
+//--------------------------------------------------------------------------------------------------------------
+/**
+ * Move mover along path
+ */
+void CTFPathFollower::Update( INextBot *bot )
+{
+	VPROF_BUDGET( "CTFPathFollower::Update", "NextBot" );
+	ILocomotion *mover = bot->GetLocomotionInterface();
+
+	// track most recent path followed
+	bot->SetCurrentPath( this );
+
+	if ( !IsValid() || m_goal == NULL )
+	{
+		return;
+	}
+
+	// check if we've reached the end of the path
+	const float nearRange = 25.0f;
+	if ( mover->IsOnGround() && ( GetEndPosition() - mover->GetFeet() ).AsVector2D().IsLengthLessThan( nearRange ) )
+	{
+		// the end of the path has been reached
+		mover->GetBot()->OnMoveToSuccess( this );
+
+		if ( bot->IsDebugging( NEXTBOT_PATH ) )
+		{
+			DevMsg( "CTFPathFollower: OnMoveToSuccess\n" );
+		}
+
+		// don't invalidate if OnMoveToSuccess just recomputed a new path
+		if ( GetAge() > 0.0f )
+		{
+			Invalidate();
+		}
+
+		return;
+	}
+
+	// move along the path
+	MoveCursorToClosestPosition( mover->GetFeet(), SEEK_AHEAD );
+	float myCursorPosition = GetCursorPosition();
+	const Path::Data &data = GetCursorData();
+
+	if ( !data.segmentPrior )
+	{
+		// this shouldn't happen
+		mover->GetBot()->OnMoveToFailure( this, FAIL_STUCK );
+		Invalidate();
+		return;
+	}
+
+	// set goal to be just ahead of wherever we happen to be on the path
+	m_goal = NextSegment( data.segmentPrior );
+
+	if ( !m_goal )
+	{
+		m_goal = data.segmentPrior;
+	}
+
+	// find actual move-to position farther down the path
+	Vector moveToPos = m_goal->pos;
+
+	// follow point farther down the path to smooth out our movement
+	for( float ahead = m_minLookAheadRange; ahead > 0.0f; ahead -= 50.0f )
+	{
+		MoveCursor( myCursorPosition, PATH_ABSOLUTE_DISTANCE );
+		MoveCursor( ahead, PATH_RELATIVE_DISTANCE );
+
+		// get path data at this lookahead point
+		const Path::Data &data = GetCursorData();
+
+		if ( mover->IsPotentiallyTraversable( mover->GetFeet(), data.pos ) )
+		{
+			moveToPos = data.pos;
+			break;
+		}
+	}
+
+	// move bot along path
+	mover->FaceTowards( moveToPos );
+	mover->Approach( moveToPos );
+
+	// debug display
+	if ( bot->IsDebugging( NEXTBOT_PATH ) )
+	{
+		Path::Draw();
+
+		NDebugOverlay::Cross3D( moveToPos, 5.0f, 150, 150, 255, true, 0.1f );
+		NDebugOverlay::Line( bot->GetEntity()->WorldSpaceCenter(), moveToPos, 255, 255, 0, true, 0.1f );
+	}
+}
+