#pragma once

#include "TerrainDefine.h"


class CTerrainFaceNormalInfo
{
public:
	struct FACENORMAL_STRUCT
	{
		K3DVector vtFaceNormalLower;
		K3DVector vtFaceNormalUpper;
	};

	CTerrainFaceNormalInfo()
		: m_rcTerrainArea( KRect( 0, 0, 0, 0 ) )
		, m_pFaceNormals( NULL )
	{
		m_DefaultFaceNormal.vtFaceNormalLower = c_DefaultNormal;
		m_DefaultFaceNormal.vtFaceNormalUpper = c_DefaultNormal;
	}
	CTerrainFaceNormalInfo( const KRect& rTerrainArea, const CTerrainInfo* pTerrainInfo = NULL )
		: m_pFaceNormals( NULL )
	{
		m_DefaultFaceNormal.vtFaceNormalLower = c_DefaultNormal;
		m_DefaultFaceNormal.vtFaceNormalUpper = c_DefaultNormal;

		Initialize( rTerrainArea, pTerrainInfo );
	}
	virtual ~CTerrainFaceNormalInfo() { Release(); }

	void Initialize( const KRect& rTerrainArea, const CTerrainInfo* pTerrainInfo = NULL )
	{
		Release();
		m_rcTerrainArea = rTerrainArea;

		int nTotalFaceNormalCount = (m_rcTerrainArea.GetWidth() * m_rcTerrainArea.GetHeight());
		m_pFaceNormals = new FACENORMAL_STRUCT[ nTotalFaceNormalCount ];

		Refresh( m_rcTerrainArea, pTerrainInfo );
	}
	void Release()
	{
		m_rcTerrainArea = KRect( 0, 0, 0, 0 );
		SAFE_DELETE_ARRAY( m_pFaceNormals );
	}

	const FACENORMAL_STRUCT* GetFaceNormalData( int nX, int nY ) const
	{
		nX -= m_rcTerrainArea.left;
		nY -= m_rcTerrainArea.top;

		return ( 0 <= nX && nX < m_rcTerrainArea.GetWidth() && 0 <= nY && nY < m_rcTerrainArea.GetHeight() )
			? (m_pFaceNormals + (nY * m_rcTerrainArea.GetWidth()) + nX) : &m_DefaultFaceNormal;
	}

	void Refresh( const KRect& rRefreshArea, const CTerrainInfo* pTerrainInfo = NULL )
	{
		int nSX = (rRefreshArea.left   < m_rcTerrainArea.left   ) ? m_rcTerrainArea.left   : rRefreshArea.left  ;
		int nSY = (rRefreshArea.top    < m_rcTerrainArea.top    ) ? m_rcTerrainArea.top    : rRefreshArea.top   ;
		int nEX = (rRefreshArea.right  > m_rcTerrainArea.right  ) ? m_rcTerrainArea.right  : rRefreshArea.right ;
		int nEY = (rRefreshArea.bottom > m_rcTerrainArea.bottom ) ? m_rcTerrainArea.bottom : rRefreshArea.bottom;

		FACENORMAL_STRUCT* pStruct = m_pFaceNormals + ( (nSY - m_rcTerrainArea.left) * m_rcTerrainArea.GetWidth() ) + (nSX - m_rcTerrainArea.top);

		if( NULL != pTerrainInfo )
		{
			for( int nY( nSY ); nY < nEY; ++nY )
			{
				for( int nX( nSX ); nX < nEX; ++nX )
				{
					K3DVertex v0 = pTerrainInfo->GetVertex( nX,     nY     );
					K3DVertex v1 = pTerrainInfo->GetVertex( nX + 1, nY     );
					K3DVertex v2 = pTerrainInfo->GetVertex( nX,     nY + 1 );
					K3DVertex v3 = pTerrainInfo->GetVertex( nX + 1, nY + 1 );

					pStruct->vtFaceNormalLower = CTerrainInfo::BuildNormalVector( v1, v0, v2 );
					pStruct->vtFaceNormalUpper = CTerrainInfo::BuildNormalVector( v1, v2, v3 );
					pStruct++;
				}
				pStruct += (m_rcTerrainArea.GetWidth() - (nEX - nSX));
			}
		}
		else
		{
			for( int nY( nSY ); nY < nEY; ++nY )
			{
				for( int nX( nSX ); nX < nEX; ++nX )
					*pStruct++ = m_DefaultFaceNormal;

				pStruct += (m_rcTerrainArea.GetWidth() - (nEX - nSX));
			}
		}
	}

private:
	KRect m_rcTerrainArea;

	FACENORMAL_STRUCT* m_pFaceNormals;
	FACENORMAL_STRUCT m_DefaultFaceNormal;
};