//========= Copyright © 1996-2005, Valve Corporation, All rights reserved. ============//
//
// Purpose: Special handling for hl2 usable ladders
//
//=============================================================================//
#include "cbase.h"
#include "hl_gamemovement.h"
#include "in_buttons.h"
#include "utlrbtree.h"
#include "hl2_shareddefs.h"

// memdbgon must be the last include file in a .cpp file!!!
#include "tier0/memdbgon.h"

static ConVar sv_autoladderdismount( "sv_autoladderdismount", "1", FCVAR_REPLICATED, "Automatically dismount from ladders when you reach the end (don't have to +USE)." );
static ConVar sv_ladderautomountdot( "sv_ladderautomountdot", "0.4", FCVAR_REPLICATED, "When auto-mounting a ladder by looking up its axis, this is the tolerance for looking now directly along the ladder axis." );

static ConVar sv_ladder_useonly( "sv_ladder_useonly", "0", FCVAR_REPLICATED, "If set, ladders can only be mounted by pressing +USE" );

#define USE_DISMOUNT_SPEED 100

//-----------------------------------------------------------------------------
// Purpose: 
//-----------------------------------------------------------------------------
CHL2GameMovement::CHL2GameMovement()
{
}

//-----------------------------------------------------------------------------
// Purpose: 
// Input  : type - 
// Output : int
//-----------------------------------------------------------------------------
int CHL2GameMovement::GetCheckInterval( IntervalType_t type )
{
	// HL2 ladders need to check every frame!!!
	if ( type == LADDER )
		return 1;

	return BaseClass::GetCheckInterval( type );
}

//-----------------------------------------------------------------------------
// Purpose: 
// Output : Returns true on success, false on failure.
//-----------------------------------------------------------------------------
bool CHL2GameMovement::IsForceMoveActive()
{
	LadderMove_t *lm = GetLadderMove();
	return lm->m_bForceLadderMove;
}

//-----------------------------------------------------------------------------
// Purpose: Debounce the USE button
//-----------------------------------------------------------------------------
void CHL2GameMovement::SwallowUseKey()
{
	mv->m_nOldButtons |= IN_USE;
	player->m_afButtonPressed &= ~IN_USE;

	GetHL2Player()->m_bPlayUseDenySound = false;
}

#if !defined( CLIENT_DLL )
// This is a simple helper class to reserver a player sized hull at a spot, owned by the current player so that nothing
//  can move into this spot and cause us to get stuck when we get there
class CReservePlayerSpot : public CBaseEntity
{
	DECLARE_CLASS( CReservePlayerSpot, CBaseEntity )
public:
	static CReservePlayerSpot *ReserveSpot( CBasePlayer *owner, const Vector& org, const Vector& mins, const Vector& maxs, bool& validspot );

	virtual void Spawn();
};

CReservePlayerSpot *CReservePlayerSpot::ReserveSpot( 
	CBasePlayer *owner, const Vector& org, const Vector& mins, const Vector& maxs, bool& validspot )
{
	CReservePlayerSpot *spot = ( CReservePlayerSpot * )CreateEntityByName( "reserved_spot" );
	Assert( spot );

	spot->SetAbsOrigin( org );
	UTIL_SetSize( spot, mins, maxs );
	spot->SetOwnerEntity( owner );
	spot->Spawn();

	// See if spot is valid
	trace_t tr;
	UTIL_TraceHull(
		org, 
		org, 
		mins,
		maxs,
		MASK_PLAYERSOLID,
		owner,
		COLLISION_GROUP_PLAYER_MOVEMENT,
		&tr );

	validspot = !tr.startsolid;

	if ( !validspot )
	{
		Vector org2 = org + Vector( 0, 0, 1 );

		// See if spot is valid
		trace_t tr;
		UTIL_TraceHull(
			org2, 
			org2, 
			mins,
			maxs,
			MASK_PLAYERSOLID,
			owner,
			COLLISION_GROUP_PLAYER_MOVEMENT,
			&tr );
		validspot = !tr.startsolid;
	}

	return spot;
}

//-----------------------------------------------------------------------------
// Purpose: 
//-----------------------------------------------------------------------------
void CReservePlayerSpot::Spawn()
{
	BaseClass::Spawn();

	SetSolid( SOLID_BBOX );
	SetMoveType( MOVETYPE_NONE );
	// Make entity invisible
	AddEffects( EF_NODRAW );
}

LINK_ENTITY_TO_CLASS( reserved_spot, CReservePlayerSpot );

#endif
//-----------------------------------------------------------------------------
// Purpose: 
// Input  : mounting - 
//			transit_speed - 
//			goalpos - 
//			*ladder - 
//-----------------------------------------------------------------------------
void CHL2GameMovement::StartForcedMove( bool mounting, float transit_speed, const Vector& goalpos, CFuncLadder *ladder )
{
	LadderMove_t* lm = GetLadderMove();
	Assert( lm );
	// Already active, just ignore
	if ( lm->m_bForceLadderMove )
	{
		return;
	}

#if !defined( CLIENT_DLL )
	if ( ladder )
	{
		ladder->PlayerGotOn( GetHL2Player() );

		// If the Ladder only wants to be there for automount checking, abort now
		if ( ladder->DontGetOnLadder() )
			return;
	}
		
	// Reserve goal slot here
	bool valid = false;
	lm->m_hReservedSpot = CReservePlayerSpot::ReserveSpot( 
		player, 
		goalpos, 
		GetPlayerMins( ( player->GetFlags() & FL_DUCKING ) ? true : false ), 
		GetPlayerMaxs( ( player->GetFlags() & FL_DUCKING ) ? true : false ), 
		valid );
	if ( !valid )
	{
		// FIXME:  Play a deny sound?
		if ( lm->m_hReservedSpot )
		{
			UTIL_Remove( lm->m_hReservedSpot );
			lm->m_hReservedSpot = NULL;
		}
		return;
	}
#endif

	// Use current player origin as start and new origin as dest
	lm->m_vecGoalPosition	= goalpos;
	lm->m_vecStartPosition	= mv->GetAbsOrigin();

	// Figure out how long it will take to make the gap based on transit_speed
	Vector delta = lm->m_vecGoalPosition - lm->m_vecStartPosition;

	float distance = delta.Length();
	
	Assert( transit_speed > 0.001f );

	// Compute time required to move that distance
	float transit_time = distance / transit_speed;
	if ( transit_time < 0.001f )
	{
		transit_time = 0.001f;
	}

	lm->m_bForceLadderMove	= true;
	lm->m_bForceMount		= mounting;

	lm->m_flStartTime		= gpGlobals->curtime;
	lm->m_flArrivalTime		= lm->m_flStartTime + transit_time;

	lm->m_hForceLadder		= ladder;

	// Don't get stuck during this traversal since we'll just be slamming the player origin
	player->SetMoveType( MOVETYPE_NONE );
	player->SetMoveCollide( MOVECOLLIDE_DEFAULT );
	player->SetSolid( SOLID_NONE );
	SetLadder( ladder );

	// Debounce the use key
	SwallowUseKey();
}

//-----------------------------------------------------------------------------
// Purpose: Returns false when finished
//-----------------------------------------------------------------------------
bool CHL2GameMovement::ContinueForcedMove()
{
	LadderMove_t* lm = GetLadderMove();
	Assert( lm );
	Assert( lm->m_bForceLadderMove );

	// Suppress regular motion
	mv->m_flForwardMove = 0.0f;
	mv->m_flSideMove = 0.0f;
	mv->m_flUpMove = 0.0f;

	// How far along are we
	float frac = ( gpGlobals->curtime - lm->m_flStartTime ) / ( lm->m_flArrivalTime - lm->m_flStartTime );
	if ( frac > 1.0f )
	{
		lm->m_bForceLadderMove = false;
#if !defined( CLIENT_DLL )
		// Remove "reservation entity"
		if ( lm->m_hReservedSpot )
		{
			UTIL_Remove( lm->m_hReservedSpot );
			lm->m_hReservedSpot = NULL;
		}
#endif
	}

	frac = clamp( frac, 0.0f, 1.0f );

	// Move origin part of the way
	Vector delta = lm->m_vecGoalPosition - lm->m_vecStartPosition;

	// Compute interpolated position
	Vector org;
	VectorMA( lm->m_vecStartPosition, frac, delta, org );
	mv->SetAbsOrigin( org );

	// If finished moving, reset player to correct movetype (or put them on the ladder)
	if ( !lm->m_bForceLadderMove )
	{
		player->SetSolid( SOLID_BBOX );
		player->SetMoveType( MOVETYPE_WALK );

		if ( lm->m_bForceMount && lm->m_hForceLadder != NULL )
		{
			player->SetMoveType( MOVETYPE_LADDER );
			SetLadder( lm->m_hForceLadder );
		}

		// Zero out any velocity
		mv->m_vecVelocity.Init();
	}

	// Stil active
	return lm->m_bForceLadderMove;
}

//-----------------------------------------------------------------------------
// Purpose: Returns true if the player is on a ladder
// Input  : &trace - ignored
//-----------------------------------------------------------------------------
bool CHL2GameMovement::OnLadder( trace_t &trace )
{
	return ( GetLadder() != NULL ) ? true : false;
}

//-----------------------------------------------------------------------------
// Purpose: 
// Input  : ladders - 
//			maxdist - 
//			**ppLadder - 
//			ladderOrigin - 
//-----------------------------------------------------------------------------
void CHL2GameMovement::Findladder( float maxdist, CFuncLadder **ppLadder, Vector& ladderOrigin, const CFuncLadder *skipLadder )
{
	CFuncLadder *bestLadder = NULL;
	float bestDist = MAX_COORD_INTEGER;
	Vector bestOrigin;

	bestOrigin.Init();

	float maxdistSqr = maxdist * maxdist;


	int c = CFuncLadder::GetLadderCount();
	for ( int i = 0 ; i < c; i++ )
	{
		CFuncLadder *ladder = CFuncLadder::GetLadder( i );

		if ( !ladder->IsEnabled() )
			continue;

		if ( skipLadder && ladder == skipLadder )
			continue;

		Vector topPosition;
		Vector bottomPosition;

		ladder->GetTopPosition( topPosition );
		ladder->GetBottomPosition( bottomPosition );

		Vector closest;
		CalcClosestPointOnLineSegment( mv->GetAbsOrigin(), bottomPosition, topPosition, closest, NULL );

		float distSqr = ( closest - mv->GetAbsOrigin() ).LengthSqr();

		// Too far away
		if ( distSqr > maxdistSqr )
		{
			continue;
		}

		// Need to trace to see if it's clear
		trace_t tr;

		UTIL_TraceLine( mv->GetAbsOrigin(), closest, 
			MASK_PLAYERSOLID,
			player,
			COLLISION_GROUP_NONE,
			&tr );

		if ( tr.fraction != 1.0f &&
			 tr.m_pEnt &&
			 tr.m_pEnt != ladder )
		{
			// Try a trace stepped up from the ground a bit, in case there's something at ground level blocking us.
			float sizez = GetPlayerMaxs().z - GetPlayerMins().z;

			UTIL_TraceLine( mv->GetAbsOrigin() + Vector( 0, 0, sizez * 0.5f ), closest, 
				MASK_PLAYERSOLID,
				player,
				COLLISION_GROUP_NONE,
				&tr );

			if ( tr.fraction != 1.0f &&
				 tr.m_pEnt &&
				 tr.m_pEnt != ladder &&
				 !tr.m_pEnt->IsSolidFlagSet( FSOLID_TRIGGER ) )
			{
				continue;
			}
		}

		// See if this is the best one so far
		if ( distSqr < bestDist )
		{
			bestDist = distSqr;
			bestLadder = ladder;
			bestOrigin = closest;
		}
	}

	// Return best ladder spot
	*ppLadder = bestLadder;
	ladderOrigin = bestOrigin;

}

static bool NearbyDismountLessFunc( const NearbyDismount_t& lhs, const NearbyDismount_t& rhs )
{
	return lhs.distSqr < rhs.distSqr;
}

void CHL2GameMovement::GetSortedDismountNodeList( const Vector &org, float radius, CFuncLadder *ladder, CUtlRBTree< NearbyDismount_t, int >& list )
{
	float radiusSqr = radius * radius;

	int i;
	int c = ladder->GetDismountCount();
	for ( i = 0; i < c; i++ )
	{
		CInfoLadderDismount *spot = ladder->GetDismount( i );
		if ( !spot )
			continue;

		float distSqr = ( spot->GetAbsOrigin() - org ).LengthSqr();
		if ( distSqr > radiusSqr )
			continue;

		NearbyDismount_t nd;
		nd.dismount = spot;
		nd.distSqr = distSqr;

		list.Insert( nd );
	}
}

//-----------------------------------------------------------------------------
// Purpose: 
//			*ladder - 
// Output : Returns true on success, false on failure.
//-----------------------------------------------------------------------------
bool CHL2GameMovement::ExitLadderViaDismountNode( CFuncLadder *ladder, bool strict, bool useAlternate )
{
	// Find the best ladder exit node
	float bestDot = -99999.0f;
	float bestDistance = 99999.0f;
	Vector bestDest;
	bool found = false;

	// For 'alternate' dismount
	bool foundAlternate = false;
	Vector alternateDest;
	float alternateDist = 99999.0f;

	CUtlRBTree< NearbyDismount_t, int >	nearbyDismounts( 0, 0, NearbyDismountLessFunc );

	GetSortedDismountNodeList( mv->GetAbsOrigin(), 100.0f, ladder, nearbyDismounts );

	int i;

	for ( i = nearbyDismounts.FirstInorder(); i != nearbyDismounts.InvalidIndex() ; i = nearbyDismounts.NextInorder( i ) )
	{
		CInfoLadderDismount *spot = nearbyDismounts[ i ].dismount;
		if ( !spot )
		{
			Assert( !"What happened to the spot!!!" );
			continue;
		}

		// See if it's valid to put the player there...
		Vector org = spot->GetAbsOrigin() + Vector( 0, 0, 1 );

		trace_t tr;
		UTIL_TraceHull(
			org, 
			org, 
			GetPlayerMins( ( player->GetFlags() & FL_DUCKING ) ? true : false ),
			GetPlayerMaxs( ( player->GetFlags() & FL_DUCKING ) ? true : false ),
			MASK_PLAYERSOLID,
			player,
			COLLISION_GROUP_PLAYER_MOVEMENT,
			&tr );

		// Nope...
		if ( tr.startsolid )
		{
			continue;
		}

		// Find the best dot product
		Vector vecToSpot = org - ( mv->GetAbsOrigin() + player->GetViewOffset() );
		vecToSpot.z = 0.0f;
		float d = VectorNormalize( vecToSpot );

		float dot = vecToSpot.Dot( m_vecForward );

		// We're not facing at it...ignore
		if ( dot < 0.5f )
		{
			if( useAlternate && d < alternateDist )
			{
				alternateDest = org;
				alternateDist = d;
				foundAlternate = true;
			}

			continue;
		}

		if ( dot > bestDot )
		{
			bestDest = org;
			bestDistance = d;
			bestDot = dot;
			found = true;
		}
	}

	if ( found )
	{
		// Require a more specific 
		if ( strict && 
			( ( bestDot < 0.7f ) || ( bestDistance > 40.0f ) ) )
		{
			return false;
		}

		StartForcedMove( false, player->MaxSpeed(), bestDest, NULL );
		return true;
	}

	if( useAlternate )
	{
		// Desperate. Don't refuse to let a person off of a ladder if it can be helped. Use the
		// alternate dismount if there is one.
		if( foundAlternate && alternateDist <= 60.0f )
		{
			StartForcedMove( false, player->MaxSpeed(), alternateDest, NULL );
			return true;
		}
	}

	return false;
}

//-----------------------------------------------------------------------------
// Purpose: 
// Input  : bOnLadder - 
//-----------------------------------------------------------------------------
void CHL2GameMovement::FullLadderMove()
{
#if !defined( CLIENT_DLL )
	CFuncLadder *ladder = GetLadder();
	Assert( ladder );
	if ( !ladder )
	{
		return;
	}

	CheckWater();

	// Was jump button pressed?  If so, don't do anything here
	if ( mv->m_nButtons & IN_JUMP )
	{
		CheckJumpButton();
		return;
	}
	else
	{
		mv->m_nOldButtons &= ~IN_JUMP;
	}

	player->SetGroundEntity( NULL );

	// Remember old positions in case we cancel this movement
	Vector oldVelocity	= mv->m_vecVelocity;
	Vector oldOrigin	= mv->GetAbsOrigin();

	Vector topPosition;
	Vector bottomPosition;

	ladder->GetTopPosition( topPosition );
	ladder->GetBottomPosition( bottomPosition );

	// Compute parametric distance along ladder vector...
	float oldt;
	CalcDistanceSqrToLine( mv->GetAbsOrigin(), topPosition, bottomPosition, &oldt );
	
	// Perform the move accounting for any base velocity.
	VectorAdd (mv->m_vecVelocity, player->GetBaseVelocity(), mv->m_vecVelocity);
	TryPlayerMove();
	VectorSubtract (mv->m_vecVelocity, player->GetBaseVelocity(), mv->m_vecVelocity);

	// Pressed buttons are "changed(xor)" and'ed with the mask of currently held buttons
	int buttonsChanged	= ( mv->m_nOldButtons ^ mv->m_nButtons );	// These buttons have changed this frame
	int buttonsPressed = buttonsChanged & mv->m_nButtons;
	bool pressed_use = ( buttonsPressed & IN_USE ) ? true : false;
	bool pressing_forward_or_side = mv->m_flForwardMove != 0.0f || mv->m_flSideMove != 0.0f;

	Vector ladderVec = topPosition - bottomPosition;
	float LadderLength = VectorNormalize( ladderVec );
	// This test is not perfect by any means, but should help a bit
	bool moving_along_ladder = false;
	if ( pressing_forward_or_side )
	{
		float fwdDot = m_vecForward.Dot( ladderVec );
		if ( fabs( fwdDot ) > 0.9f )
		{
			moving_along_ladder = true;
		}
	}

	// Compute parametric distance along ladder vector...
	float newt;
	CalcDistanceSqrToLine( mv->GetAbsOrigin(), topPosition, bottomPosition, &newt );

	// Fudge of 2 units
	float tolerance = 1.0f / LadderLength;

	bool wouldleaveladder = false;
	// Moving pPast top or bottom?
	if ( newt < -tolerance )
	{
		wouldleaveladder = newt < oldt;
	}
	else if ( newt > ( 1.0f + tolerance ) )
	{
		wouldleaveladder = newt > oldt;
	}

	// See if we are near the top or bottom but not moving
	float dist1sqr, dist2sqr;

	dist1sqr = ( topPosition - mv->GetAbsOrigin() ).LengthSqr();
	dist2sqr = ( bottomPosition - mv->GetAbsOrigin() ).LengthSqr();

	float dist = min( dist1sqr, dist2sqr );
	bool neardismountnode = ( dist < 16.0f * 16.0f ) ? true : false;
	float ladderUnitsPerTick = ( MAX_CLIMB_SPEED * gpGlobals->interval_per_tick );
	bool neardismountnode2 = ( dist < ladderUnitsPerTick * ladderUnitsPerTick ) ? true : false;

	// Really close to node, cvar is set, and pressing a key, then simulate a +USE
	bool auto_dismount_use = ( neardismountnode2 && 
								sv_autoladderdismount.GetBool() && 
								pressing_forward_or_side && 
								!moving_along_ladder );

	bool fully_underwater = ( player->GetWaterLevel() == WL_Eyes ) ? true : false;

	// If the user manually pressed use or we're simulating it, then use_dismount will occur
	bool use_dismount = pressed_use || auto_dismount_use;

	if ( fully_underwater && !use_dismount )
	{
		// If fully underwater, we require looking directly at a dismount node 
		///  to "float off" a ladder mid way...
		if ( ExitLadderViaDismountNode( ladder, true ) )
		{
			// See if they +used a dismount point mid-span..
			return;
		}
	}

	// If the movement would leave the ladder and they're not automated or pressing use, disallow the movement
	if ( !use_dismount )
	{
		if ( wouldleaveladder )
		{
			// Don't let them leave the ladder if they were on it
			mv->m_vecVelocity = oldVelocity;
			mv->SetAbsOrigin( oldOrigin );
		}
		return;
	}

	// If the move would not leave the ladder and we're near close to the end, then just accept the move
	if ( !wouldleaveladder && !neardismountnode )
	{
		// Otherwise, if the move would leave the ladder, disallow it.
		if ( pressed_use )
		{
			if ( ExitLadderViaDismountNode( ladder, false, IsX360() ) )
			{
				// See if they +used a dismount point mid-span..
				return;
			}

			player->SetMoveType( MOVETYPE_WALK );
			player->SetMoveCollide( MOVECOLLIDE_DEFAULT );
			SetLadder( NULL );
			GetHL2Player()->m_bPlayUseDenySound = false;

			// Dismount with a bit of velocity in facing direction
			VectorScale( m_vecForward, USE_DISMOUNT_SPEED, mv->m_vecVelocity );
			mv->m_vecVelocity.z = 50;
		}
		return;
	}

	// Debounce the use key
	if ( pressed_use )
	{
		SwallowUseKey();
	}

	// Try auto exit, if possible
	if ( ExitLadderViaDismountNode( ladder, false, pressed_use ) )
	{
		return;
	}

	if ( wouldleaveladder )
	{
		// Otherwise, if the move would leave the ladder, disallow it.
		if ( pressed_use )
		{
			player->SetMoveType( MOVETYPE_WALK );
			player->SetMoveCollide( MOVECOLLIDE_DEFAULT );
			SetLadder( NULL );

			// Dismount with a bit of velocity in facing direction
			VectorScale( m_vecForward, USE_DISMOUNT_SPEED, mv->m_vecVelocity );
			mv->m_vecVelocity.z = 50;
		}
		else
		{
			mv->m_vecVelocity = oldVelocity;
			mv->SetAbsOrigin( oldOrigin );
		}
	}
#endif
}

bool CHL2GameMovement::CheckLadderAutoMountEndPoint( CFuncLadder *ladder, const Vector& bestOrigin )
{
	// See if we're really near an endpoint
	if ( !ladder )
		return false;

	Vector top, bottom;
	ladder->GetTopPosition( top );
	ladder->GetBottomPosition( bottom );

	float d1, d2;

	d1 = ( top - mv->GetAbsOrigin() ).LengthSqr();
	d2 = ( bottom - mv->GetAbsOrigin() ).LengthSqr();

	if ( d1 > 16 * 16 && d2 > 16 * 16 )
		return false;

	Vector ladderAxis;

	if ( d1 < 16 * 16 )
	{
		// Close to top
		ladderAxis = bottom - top;
	}
	else
	{
		ladderAxis = top - bottom;
	}

	VectorNormalize( ladderAxis );

	if ( ladderAxis.Dot( m_vecForward ) > sv_ladderautomountdot.GetFloat() )
	{
		StartForcedMove( true, player->MaxSpeed(), bestOrigin, ladder );
		return true;
	}

	return false;
}

bool CHL2GameMovement::CheckLadderAutoMountCone( CFuncLadder *ladder, const Vector& bestOrigin, float maxAngleDelta, float maxDistToLadder )
{
	// Never 'back' onto ladders or stafe onto ladders
	if ( ladder != NULL && 
		( mv->m_flForwardMove > 0.0f ) )
	{
		Vector top, bottom;
		ladder->GetTopPosition( top );
		ladder->GetBottomPosition( bottom );

		Vector ladderAxis = top - bottom;
		VectorNormalize( ladderAxis );

		Vector probe = mv->GetAbsOrigin();

		Vector closest;
		CalcClosestPointOnLineSegment( probe, bottom, top, closest, NULL );

		Vector vecToLadder = closest - probe;

		float dist = VectorNormalize( vecToLadder );

		Vector flatLadder = vecToLadder;
		flatLadder.z = 0.0f;
		Vector flatForward = m_vecForward;
		flatForward.z = 0.0f;

		VectorNormalize( flatLadder );
		VectorNormalize( flatForward );

		float facingDot = flatForward.Dot( flatLadder );
		float angle = acos( facingDot ) * 180 / M_PI;

		bool closetoladder = ( dist != 0.0f && dist < maxDistToLadder ) ? true : false;
		bool reallyclosetoladder = ( dist != 0.0f && dist < 4.0f ) ? true : false;

		bool facingladderaxis = ( angle < maxAngleDelta ) ? true : false;
		bool facingalongaxis = ( (float)fabs( ladderAxis.Dot( m_vecForward ) ) > sv_ladderautomountdot.GetFloat() ) ? true : false;
#if 0
		Msg( "close %i length %.3f maxdist %.3f facing %.3f dot %.3f ang %.3f\n",
			closetoladder ? 1 : 0,
			dist,
			maxDistToLadder,
			(float)fabs( ladderAxis.Dot( m_vecForward ) ),
			facingDot, 
			angle);
#endif

		// Tracker 21776:  Don't mount ladders this way if strafing
		bool strafing = ( fabs( mv->m_flSideMove ) < 1.0f ) ? false : true;

		if ( ( ( facingDot > 0.0f && !strafing ) || facingalongaxis  ) && 
			( facingladderaxis || reallyclosetoladder ) && 
			closetoladder )
		{
			StartForcedMove( true, player->MaxSpeed(), bestOrigin, ladder );
			return true;
		}
	}

	return false;
}

//-----------------------------------------------------------------------------
// Purpose: Must be facing toward ladder
// Input  : *ladder - 
// Output : Returns true on success, false on failure.
//-----------------------------------------------------------------------------
bool CHL2GameMovement::LookingAtLadder( CFuncLadder *ladder )
{
	if ( !ladder )
	{
		return false;
	}

	// Get ladder end points
	Vector top, bottom;
	ladder->GetTopPosition( top );
	ladder->GetBottomPosition( bottom );

	// Find closest point on ladder to player (could be an endpoint)
	Vector closest;
	CalcClosestPointOnLineSegment( mv->GetAbsOrigin(), bottom, top, closest, NULL );

	// Flatten our view direction to 2D
	Vector flatForward = m_vecForward;
	flatForward.z = 0.0f;

	// Because the ladder itself is not a solid, the player's origin may actually be 
	// permitted to pass it, and that will screw up our dot product.
	// So back up the player's origin a bit to do the facing calculation.
	Vector vecAdjustedOrigin = mv->GetAbsOrigin() - 8.0f * flatForward;

	// Figure out vector from player to closest point on ladder
	Vector vecToLadder = closest - vecAdjustedOrigin;

	// Flatten it to 2D
	Vector flatLadder = vecToLadder;
	flatLadder.z = 0.0f;

	// Normalize the vectors (unnecessary)
	VectorNormalize( flatLadder );
	VectorNormalize( flatForward );

	// Compute dot product to see if forward is in same direction as vec to ladder
	float facingDot = flatForward.Dot( flatLadder );

	float requiredDot = ( sv_ladder_useonly.GetBool() ) ? -0.99 : 0.0;

	// Facing same direction if dot > = requiredDot...
	bool facingladder = ( facingDot >= requiredDot );

	return facingladder;
}

//-----------------------------------------------------------------------------
// Purpose: 
// Input  : &trace - 
//-----------------------------------------------------------------------------
bool CHL2GameMovement::CheckLadderAutoMount( CFuncLadder *ladder, const Vector& bestOrigin )
{
#if !defined( CLIENT_DLL )

	if ( ladder != NULL )
	{
		StartForcedMove( true, player->MaxSpeed(), bestOrigin, ladder );
		return true;
	}

#endif
	return false;
}

//-----------------------------------------------------------------------------
// Purpose: 
//-----------------------------------------------------------------------------
bool CHL2GameMovement::LadderMove( void )
{

	if ( player->GetMoveType() == MOVETYPE_NOCLIP ||
		player->GetMoveType() == MOVETYPE_RTS )
	{
		SetLadder( NULL );
		return false;
	}

	// If being forced to mount/dismount continue to act like we are on the ladder
	if ( IsForceMoveActive() && ContinueForcedMove() )
	{
		return true;
	}

	CFuncLadder *bestLadder = NULL;
	Vector bestOrigin( 0, 0, 0 );

	CFuncLadder *ladder = GetLadder();

	// Something 1) deactivated the ladder...  or 2) something external applied
	//  a force to us.  In either case  make the player fall, etc.
	if ( ladder && 
		 ( !ladder->IsEnabled() ||
		 ( player->GetBaseVelocity().LengthSqr() > 1.0f ) ) )
	{
		GetHL2Player()->ExitLadder();
		ladder = NULL;
	}

	if ( !ladder )
	{
		Findladder( 64.0f, &bestLadder, bestOrigin, NULL );
	}

#if !defined (CLIENT_DLL)
	if( !ladder && bestLadder && sv_ladder_useonly.GetBool() )
	{
		GetHL2Player()->DisplayLadderHudHint();
	}
#endif

	int buttonsChanged	= ( mv->m_nOldButtons ^ mv->m_nButtons );	// These buttons have changed this frame
	int buttonsPressed = buttonsChanged & mv->m_nButtons;
	bool pressed_use = ( buttonsPressed & IN_USE ) ? true : false;

	// If I'm already moving on a ladder, use the previous ladder direction
	if ( !ladder && !pressed_use )
	{
		// If flying through air, allow mounting ladders if we are facing < 15 degress from the ladder and we are close
		if ( !ladder && !sv_ladder_useonly.GetBool() )
		{
			// Tracker 6625:  Don't need to be leaping to auto mount using this method...
			// But if we are on the ground, then we must not be backing into the ladder (Tracker 12961)
			bool onground = player->GetGroundEntity() ? true : false;
			if ( !onground || ( mv->m_flForwardMove > 0.0f ) )
			{
				if ( CheckLadderAutoMountCone( bestLadder, bestOrigin, 15.0f, 32.0f ) )
				{
					return true;
				}
			}
			
			// Pressing forward while looking at ladder and standing (or floating) near a mounting point
			if ( mv->m_flForwardMove > 0.0f )
			{
				if ( CheckLadderAutoMountEndPoint( bestLadder, bestOrigin ) )
				{
					return true;
				}
			}
		}

		return false;
	}

	if ( !ladder && 
		LookingAtLadder( bestLadder ) &&
		CheckLadderAutoMount( bestLadder, bestOrigin ) )
	{
		return true;
	}

	// Reassign the ladder
	ladder = GetLadder();
	if ( !ladder )
	{
		return false;
	}

	// Don't play the deny sound
	if ( pressed_use )
	{
		GetHL2Player()->m_bPlayUseDenySound = false;
	}

	// Make sure we are on the ladder
	player->SetMoveType( MOVETYPE_LADDER );
	player->SetMoveCollide( MOVECOLLIDE_DEFAULT );

	player->SetGravity( 0.0f );
	
	float forwardSpeed = 0.0f;
	float rightSpeed = 0.0f;

	float speed = player->MaxSpeed();


	if ( mv->m_nButtons & IN_BACK )
	{
		forwardSpeed -= speed;
	}
	
	if ( mv->m_nButtons & IN_FORWARD )
	{
		forwardSpeed += speed;
	}
	
	if ( mv->m_nButtons & IN_MOVELEFT )
	{
		rightSpeed -= speed;
	}
	
	if ( mv->m_nButtons & IN_MOVERIGHT )
	{
		rightSpeed += speed;
	}
	
	if ( mv->m_nButtons & IN_JUMP )
	{
		player->SetMoveType( MOVETYPE_WALK );
		// Remove from ladder
		SetLadder( NULL );

		// Jump in view direction
		Vector jumpDir = m_vecForward;

		// unless pressing backward or something like that
		if ( mv->m_flForwardMove < 0.0f )
		{
			jumpDir = -jumpDir;
		}

		VectorNormalize( jumpDir );

		VectorScale( jumpDir, MAX_CLIMB_SPEED, mv->m_vecVelocity );
		// Tracker 13558:  Don't add any extra z velocity if facing downward at all
		if ( m_vecForward.z >= 0.0f )
		{
			mv->m_vecVelocity.z = mv->m_vecVelocity.z + 50;
		}
		return false;
	}

	if ( forwardSpeed != 0 || rightSpeed != 0 )
	{
		// See if the player is looking toward the top or the bottom
		Vector velocity;

		VectorScale( m_vecForward, forwardSpeed, velocity );
		VectorMA( velocity, rightSpeed, m_vecRight, velocity );

		VectorNormalize( velocity );

		Vector ladderUp;
		ladder->ComputeLadderDir( ladderUp );
		VectorNormalize( ladderUp );

		Vector topPosition;
		Vector bottomPosition;

		ladder->GetTopPosition( topPosition );
		ladder->GetBottomPosition( bottomPosition );

		// Check to see if we've mounted the ladder in a bogus spot and, if so, just fall off the ladder...
		float dummyt = 0.0f;
		float distFromLadderSqr = CalcDistanceSqrToLine( mv->GetAbsOrigin(), topPosition, bottomPosition, &dummyt );
		if ( distFromLadderSqr > 36.0f )
		{
			// Uh oh, we fell off zee ladder...
			player->SetMoveType( MOVETYPE_WALK );
			// Remove from ladder
			SetLadder( NULL );
			return false;
		}

		bool ishorizontal = fabs( topPosition.z - bottomPosition.z ) < 64.0f ? true : false;

		float changeover = ishorizontal ? 0.0f : 0.3f;

		float factor = 1.0f;
		if ( velocity.z >= 0 )
		{
			float dotTop = ladderUp.Dot( velocity );
			if ( dotTop < -changeover )
			{
				// Aimed at bottom
				factor = -1.0f;
			}
		}
		else
		{
			float dotBottom = -ladderUp.Dot( velocity );
			if ( dotBottom > changeover )
			{
				factor = -1.0f;
			}
		}

#ifdef _XBOX
		if( sv_ladders_useonly.GetBool() )
		{
			// Stick up climbs up, stick down climbs down. No matter which way you're looking.
			if ( mv->m_nButtons & IN_FORWARD )
			{
				factor = 1.0f;
			}
			else if( mv->m_nButtons & IN_BACK )
			{
				factor = -1.0f;
			}
		}
#endif//_XBOX

		mv->m_vecVelocity = MAX_CLIMB_SPEED * factor * ladderUp;
	}
	else
	{
		mv->m_vecVelocity.Init();
	}

	return true;
}

void CHL2GameMovement::SetGroundEntity( trace_t *pm )
{
	CBaseEntity *newGround = pm ? pm->m_pEnt : NULL;

	//Adrian: Special case for combine balls.
	if ( newGround && newGround->GetCollisionGroup() == HL2COLLISION_GROUP_COMBINE_BALL_NPC )
	{
		return;
	}

	BaseClass::SetGroundEntity( pm );
}

bool CHL2GameMovement::CanAccelerate()
{
#ifdef HL2MP 
	if ( player->IsObserver() )
	{
		return true;
	}
#endif

	BaseClass::CanAccelerate();

	return true;
}


#ifndef PORTAL	// Portal inherits from this but needs to declare it's own global interface
	// Expose our interface.
	static CHL2GameMovement g_GameMovement;
	IGameMovement *g_pGameMovement = ( IGameMovement * )&g_GameMovement;

	EXPOSE_SINGLE_INTERFACE_GLOBALVAR(CGameMovement, IGameMovement,INTERFACENAME_GAMEMOVEMENT, g_GameMovement );
#endif