source-engine/game/server/cplane.cpp

//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose: 
//
// $NoKeywords: $
//=============================================================================//
#include "cbase.h"
#include "game.h"
#include "cplane.h"

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

//=========================================================
// Plane
//=========================================================
CPlane::CPlane ( void )
{
	m_fInitialized = FALSE;
}

//=========================================================
// InitializePlane - Takes a normal for the plane and a
// point on the plane and 
//=========================================================
void CPlane::InitializePlane ( const Vector &vecNormal, const Vector &vecPoint )
{
	m_vecNormal = vecNormal;
	m_flDist = DotProduct ( m_vecNormal, vecPoint );
	m_fInitialized = TRUE;
}


//=========================================================
// PointInFront - determines whether the given vector is 
// in front of the plane. 
//=========================================================
bool CPlane::PointInFront ( const Vector &vecPoint )
{
	float flFace;

	if ( !m_fInitialized )
	{
		return FALSE;
	}

	flFace = DotProduct ( m_vecNormal, vecPoint ) - m_flDist;

	if ( flFace >= 0 )
	{
		return TRUE;
	}

	return FALSE;
}

//=========================================================
//=========================================================
float CPlane::PointDist ( const Vector &vecPoint )
{
	float flDist;

	if ( !m_fInitialized )
	{
		return FALSE;
	}

	flDist = DotProduct ( m_vecNormal, vecPoint ) - m_flDist;

	return flDist;
}