bool CFlashlightEffect::ComputeLightPosAndOrientation( const Vector &vecPos, const Vector &vecForward, const Vector &vecRight, const Vector &vecUp,
														Vector& vecFinalPos, Quaternion& quatOrientation, bool bTracePlayers )
{
	const float flEpsilon = 0.1f;			// Offset flashlight position along vecUp
	float flDistCutoff = r_flashlighttracedistcutoff.GetFloat();
	const float flDistDrag = 0.2;
	bool bDebugVis = r_flashlightvisualizetrace.GetBool();

	C_BasePlayer *pPlayer = UTIL_PlayerByIndex( m_nEntIndex );
	if ( !pPlayer )
	{

		pPlayer = C_BasePlayer::GetLocalPlayer();

		if ( !pPlayer )
		{
			Assert( false );
			return false;
		}
	}

	// We will lock some of the flashlight params if player is on a ladder, to prevent oscillations due to the trace-rays
	bool bPlayerOnLadder = ( pPlayer->GetMoveType() == MOVETYPE_LADDER );

	CTraceFilterSkipPlayerAndViewModel traceFilter( pPlayer, bTracePlayers );

	//	Vector vOrigin = vecPos + r_flashlightoffsety.GetFloat() * vecUp;
	Vector vecOffset;
	pPlayer->GetFlashlightOffset( vecForward, vecRight, vecUp, &vecOffset );
	Vector vOrigin = vecPos + vecOffset;

	// Not on ladder...trace a hull
	if ( !bPlayerOnLadder ) 
	{
		Vector vecPlayerEyePos = pPlayer->GetRenderOrigin() + pPlayer->GetViewOffset();

		trace_t pmOriginTrace;
		UTIL_TraceHull( vecPlayerEyePos, vOrigin, Vector(-2, -2, -2), Vector(2, 2, 2), ( MASK_SOLID & ~(CONTENTS_HITBOX) ) | CONTENTS_WINDOW | CONTENTS_GRATE, &traceFilter, &pmOriginTrace );//1

		if ( bDebugVis )
		{
			debugoverlay->AddBoxOverlay( pmOriginTrace.endpos, Vector( -2, -2, -2 ), Vector( 2, 2, 2 ), QAngle( 0, 0, 0 ), 0, 255, 0, 16, 0 );
			if ( pmOriginTrace.DidHit() || pmOriginTrace.startsolid )
			{
				debugoverlay->AddLineOverlay( pmOriginTrace.startpos, pmOriginTrace.endpos, 255, 128, 128, true, 0 );
			}
			else
			{
				debugoverlay->AddLineOverlay( pmOriginTrace.startpos, pmOriginTrace.endpos, 255, 0, 0, true, 0 );
			}
		}

		if ( pmOriginTrace.DidHit() || pmOriginTrace.startsolid )
		{
			vOrigin = pmOriginTrace.endpos;
		}
		else
		{
			if ( pPlayer->m_vecFlashlightOrigin != vecPlayerEyePos )
			{
				vOrigin = vecPos;
			}
		}
	}
	else // on ladder...skip the above hull trace
	{
		vOrigin = vecPos;
	}

	// Now do a trace along the flashlight direction to ensure there is nothing within range to pull back from
	int iMask = MASK_OPAQUE_AND_NPCS;
	iMask &= ~CONTENTS_HITBOX;
	iMask |= CONTENTS_WINDOW | CONTENTS_GRATE | CONTENTS_IGNORE_NODRAW_OPAQUE;

	Vector vTarget = vOrigin + vecForward * r_flashlightfar.GetFloat();

	// Work with these local copies of the basis for the rest of the function
	Vector vDir   = vTarget - vOrigin;
	Vector vRight = vecRight;
	Vector vUp    = vecUp;
	VectorNormalize( vDir   );
	VectorNormalize( vRight );
	VectorNormalize( vUp    );

	// Orthonormalize the basis, since the flashlight texture projection will require this later...
	vUp -= DotProduct( vDir, vUp ) * vDir;
	VectorNormalize( vUp );
	vRight -= DotProduct( vDir, vRight ) * vDir;
	VectorNormalize( vRight );
	vRight -= DotProduct( vUp, vRight ) * vUp;
	VectorNormalize( vRight );

	AssertFloatEquals( DotProduct( vDir, vRight ), 0.0f, 1e-3 );
	AssertFloatEquals( DotProduct( vDir, vUp    ), 0.0f, 1e-3 );
	AssertFloatEquals( DotProduct( vRight, vUp  ), 0.0f, 1e-3 );

	trace_t pmDirectionTrace;
	UTIL_TraceHull( vOrigin, vTarget, Vector( -1.5, -1.5, -1.5 ), Vector( 1.5, 1.5, 1.5 ), iMask, &traceFilter, &pmDirectionTrace );//.5

	if ( bDebugVis )
	{
		debugoverlay->AddBoxOverlay( pmDirectionTrace.endpos, Vector( -4, -4, -4 ), Vector( 4, 4, 4 ), QAngle( 0, 0, 0 ), 0, 0, 255, 16, 0 );
		debugoverlay->AddLineOverlay( vOrigin, pmDirectionTrace.endpos, 255, 0, 0, false, 0 );
	}

	float flTargetPullBackDist = 0.0f;
	float flDist = (pmDirectionTrace.endpos - vOrigin).Length();

	if ( flDist < flDistCutoff )
	{
		// We have an intersection with our cutoff range
		// Determine how far to pull back, then trace to see if we are clear
		float flPullBackDist = bPlayerOnLadder ? r_flashlightladderdist.GetFloat() : flDistCutoff - flDist;	// Fixed pull-back distance if on ladder

		flTargetPullBackDist = flPullBackDist;

		if ( !bPlayerOnLadder )
		{
			trace_t pmBackTrace;
			// start the trace away from the actual trace origin a bit, to avoid getting stuck on small, close "lips"
			UTIL_TraceHull( vOrigin - vDir * ( flDistCutoff * r_flashlightbacktraceoffset.GetFloat() ), vOrigin - vDir * ( flPullBackDist - flEpsilon ),
				Vector( -1.5f, -1.5f, -1.5f ), Vector( 1.5f, 1.5f, 1.5f ), iMask, &traceFilter, &pmBackTrace );

			if ( bDebugVis )
			{
				debugoverlay->AddLineOverlay( pmBackTrace.startpos, pmBackTrace.endpos, 255, 0, 255, true, 0 );
			}

			if( pmBackTrace.DidHit() )
			{
				// We have an intersection behind us as well, so limit our flTargetPullBackDist
				float flMaxDist = (pmBackTrace.endpos - vOrigin).Length() - flEpsilon;
				flTargetPullBackDist = MIN( flMaxDist, flTargetPullBackDist );
				//m_flCurrentPullBackDist = MIN( flMaxDist, m_flCurrentPullBackDist );	// possible pop
			}
		}
	}

	if ( bDebugVis )
	{
		// visualize pullback
		debugoverlay->AddBoxOverlay( vOrigin - vDir * m_flCurrentPullBackDist, Vector( -2, -2, -2 ), Vector( 2, 2, 2 ), QAngle( 0, 0, 0 ), 255, 255, 0, 16, 0 );
		debugoverlay->AddBoxOverlay( vOrigin - vDir * flTargetPullBackDist, Vector( -1, -1, -1 ), Vector( 1, 1, 1 ), QAngle( 0, 0, 0 ), 128, 128, 0, 16, 0 );
	}

	m_flCurrentPullBackDist = Lerp( flDistDrag, m_flCurrentPullBackDist, flTargetPullBackDist );
	m_flCurrentPullBackDist = MIN( m_flCurrentPullBackDist, flDistCutoff );	// clamp to max pullback dist
	vOrigin = vOrigin - vDir * m_flCurrentPullBackDist;

	vecFinalPos = vOrigin;
	BasisToQuaternion( vDir, vRight, vUp, quatOrientation );

	return true;
}
void CSDKInput::CAM_Think( void )
{
	VPROF("CAM_Think");

	Vector idealAngles;
	Vector camOffset;
	QAngle viewangles;
	
	if( !CAM_IsThirdPerson() )
		return;

	ConVarRef cam_idealpitch( "cam_idealpitch" );
	ConVarRef cam_idealyaw( "cam_idealyaw" );
	ConVarRef cam_idealdist( "cam_idealdist" );

	idealAngles[ PITCH ] = cam_idealpitch.GetFloat();
	idealAngles[ YAW ]   = cam_idealyaw.GetFloat();
	idealAngles[ DIST ]  = cam_idealdist.GetFloat();

	// Obtain engine view angles and if they popped while the camera was static,
	// fix the camera angles as well
	engine->GetViewAngles( viewangles );

	// bring the pitch values back into a range that MoveToward can handle
	if ( idealAngles[ PITCH ] > 180 )
		idealAngles[ PITCH ] -= 360;
	else if ( idealAngles[ PITCH ] < -180 )
		idealAngles[ PITCH ] += 360;

	// bring the yaw values back into a range that MoveToward can handle
	// --
	// Vitaliy: going with >= 180 and <= -180.
	// This introduces a potential discontinuity when looking directly at model face
	// as camera yaw will be jumping from +180 to -180 and back, but when working with
	// the camera allows smooth rotational transitions from left to right and back.
	// Otherwise one of the transitions that has ">"-comparison will be locked.
	// --
	if ( idealAngles[ YAW ] >= 180 )
		idealAngles[ YAW ] -= 360;
	else if ( idealAngles[ YAW ] <= -180 )
		idealAngles[ YAW ] += 360;

	ConVarRef c_minpitch( "c_minpitch" );
	ConVarRef c_maxpitch( "c_maxpitch" );
	ConVarRef c_minyaw( "c_minyaw" );
	ConVarRef c_maxyaw( "c_maxyaw" );
	ConVarRef c_mindistance( "c_mindistance" );
	ConVarRef c_maxdistance( "c_maxdistance" );

	// clamp pitch, yaw and dist...
	idealAngles[ PITCH ] = clamp( idealAngles[ PITCH ], c_minpitch.GetFloat(), c_maxpitch.GetFloat() );
	idealAngles[ YAW ]   = clamp( idealAngles[ YAW ], c_minyaw.GetFloat(), c_maxyaw.GetFloat() );
	idealAngles[ DIST ]  = clamp( idealAngles[ DIST ], c_mindistance.GetFloat(), c_maxdistance.GetFloat() );

	// update ideal angles
	cam_idealpitch.SetValue( idealAngles[ PITCH ] );
	cam_idealyaw.SetValue( idealAngles[ YAW ] );
	cam_idealdist.SetValue( idealAngles[ DIST ] );
	
	// Move the CameraOffset "towards" the idealAngles
	// Note: CameraOffset = viewangle + idealAngle
	CAM_GetCameraOffset( camOffset );

	ConVarRef cam_snapto( "cam_snapto" );
	if( cam_snapto.GetInt() )
	{
		camOffset[ YAW ] = cam_idealyaw.GetFloat() + viewangles[ YAW ];
		camOffset[ PITCH ] = cam_idealpitch.GetFloat() + viewangles[ PITCH ];
		camOffset[ DIST ] = cam_idealdist.GetFloat();
	}
	else
	{
		ConVarRef cam_ideallag( "cam_ideallag" );
		float lag = max( 1, 1 + cam_ideallag.GetFloat() );

		if( camOffset[ YAW ] - viewangles[ YAW ] != cam_idealyaw.GetFloat() )
			camOffset[ YAW ] = MoveToward( camOffset[ YAW ], cam_idealyaw.GetFloat() + viewangles[ YAW ], lag );
		
		if( camOffset[ PITCH ] - viewangles[ PITCH ] != cam_idealpitch.GetFloat() )
			camOffset[ PITCH ] = MoveToward( camOffset[ PITCH ], cam_idealpitch.GetFloat() + viewangles[ PITCH ], lag );
		
		if( abs( camOffset[ DIST ] - cam_idealdist.GetFloat() ) < 2.0 )
			camOffset[ DIST ] = cam_idealdist.GetFloat();
		else
			camOffset[ DIST ] += ( cam_idealdist.GetFloat() - camOffset[ DIST ] ) / lag;
	}

	// move the camera closer to the player if it hit something
	trace_t trace;
	C_BasePlayer* localPlayer = C_BasePlayer::GetLocalPlayer();

	if ( localPlayer )
	{
		Vector camForward;

		// find our player's origin, and from there, the eye position
		Vector origin = localPlayer->GetLocalOrigin();
		origin += localPlayer->GetViewOffset();

		// get the forward vector
		AngleVectors( QAngle(camOffset[ PITCH ], camOffset[ YAW ], 0), &camForward, NULL, NULL );

		// use our previously #defined hull to collision trace
		CTraceFilterSimple traceFilter( localPlayer, COLLISION_GROUP_NONE );
		UTIL_TraceHull( origin, origin - (camForward * camOffset[ DIST ]),
			Vector(-CAM_HULL_OFFSET, -CAM_HULL_OFFSET, -CAM_HULL_OFFSET), Vector(CAM_HULL_OFFSET, CAM_HULL_OFFSET, CAM_HULL_OFFSET),
			MASK_SOLID, &traceFilter, &trace );

		// move the camera closer if it hit something
		if( trace.fraction < 1.0 )
		{
			camOffset[ DIST ] *= trace.fraction;
		}

		// For now, I'd rather see the insade of a player model than punch the camera through a wall
		// might try the fade out trick at some point
		//if( camOffset[ DIST ] < CAM_MIN_DIST )
		//    camOffset[ DIST ] = CAM_MIN_DIST; // clamp up to minimum
	}

	ConVarRef cam_showangles( "cam_showangles" );
	if ( cam_showangles.GetInt() )
	{
		engine->Con_NPrintf( 4, "Pitch: %6.1f   Yaw: %6.1f %38s", viewangles[ PITCH ], viewangles[ YAW ], "view angles" );
		engine->Con_NPrintf( 6, "Pitch: %6.1f   Yaw: %6.1f   Dist: %6.1f %19s", cam_idealpitch.GetFloat(), cam_idealyaw.GetFloat(), cam_idealdist.GetFloat(), "ideal angles" );
		engine->Con_NPrintf( 8, "Pitch: %6.1f   Yaw: %6.1f   Dist: %6.1f %16s", camOffset[ PITCH ], camOffset[ YAW ], camOffset[ DIST ], "camera offset" );
	}

	QAngle angOffset;
	angOffset.x = camOffset.x;
	angOffset.y = camOffset.y;
	angOffset.z = camOffset.z;

	CAM_SetCameraThirdData(NULL, angOffset);
}