Authoring a Logical Entity/Code

//===== Copyright © 1996-2005, Valve Corporation, All rights reserved. ========
//
// Purpose: Simple logical entity that counts up to a threshold value, then
//			fires an output when reached.
//
//=============================================================================

#include "cbase.h"

class CMyLogicalEntity : public CLogicalEntity
{
public:
	DECLARE_CLASS( CMyLogicalEntity, CLogicalEntity );
	DECLARE_DATADESC();

	// Constructor
	CMyLogicalEntity ( void ) : m_nCounter( 0 ) {}
 
	// Input function
	void InputTick( inputdata_t &inputData );

private:

	int	m_nThreshold;	// Count at which to fire our output
	int	m_nCounter;	// Internal counter

	COutputEvent	m_OnThreshold;	// Output event when the counter reaches the threshold
};

LINK_ENTITY_TO_CLASS( my_logical_entity, CMyLogicalEntity  );

// Start of our data description for the class
BEGIN_DATADESC( CMyLogicalEntity  )
	
	// For save/load
	DEFINE_FIELD( m_nCounter, FIELD_INTEGER ),

	// Links our member variable to our keyvalue from Hammer
	DEFINE_KEYFIELD( m_nThreshold, FIELD_INTEGER, "threshold" ),

	// Links our input name from Hammer to our input member function
	DEFINE_INPUTFUNC( FIELD_VOID, "Tick", InputTick ),

	// Links our output member to the output name used by Hammer
	DEFINE_OUTPUT( m_OnThreshold, "OnThreshold" ),

END_DATADESC()

//-----------------------------------------------------------------------------
// Purpose: Handle a tick input from another entity
//-----------------------------------------------------------------------------
void CMyLogicalEntity::InputTick( inputdata_t &inputData )
{
	// Increment our counter
	m_nCounter++;

	// See if we've met or crossed our threshold value
	if ( m_nCounter >= m_nThreshold )
	{
		// Fire an output event
		m_OnThreshold.FireOutput( inputData.pActivator, this );
		
		// Reset our counter
		m_nCounter = 0;
	}
}