Rendering a 2d tilemap

  
int CTileMap::Resize(int NumXTiles, int NumYTiles)
{
	//re-create

	m_NumXTiles = NumXTiles;
	m_NumYTiles = NumYTiles;

	m_NumVertices = (m_NumXTiles+1)*(m_NumYTiles+1);
	m_NumPolygons = m_NumXTiles*m_NumYTiles*2;
	m_NumIndices = m_NumYTiles*m_NumXTiles*6;


	if(m_Tiles)
	{
		for(int n = 0; n < m_NumXTiles; n++)
		{
			delete m_Tiles[n];
		}

		delete [] m_Tiles;

		m_Tiles = NULL;
	}

	m_Tiles = new CTile*[m_NumXTiles];

	for(int n = 0; n < m_NumXTiles; n++)
	{
		m_Tiles[n] = new CTile[NumYTiles];
	}

	for(int y = 0; y < m_NumYTiles; y++)
	{
		for(int x = 0; x < m_NumXTiles; x++)
		{
			m_Tiles[y][x].TileHandle = 0; //invalid

		}
	}
	

	//free the vbuffer

	if(m_pVBuffer)
	{
		delete 	m_pVBuffer;
	}

	m_pVBuffer = new CVertexBuffer();

	//recreate vertex buffer

	if(!m_pVBuffer->Create(m_NumVertices,sizeof(s3DVertex),_3DVERTEX)) g_Log.Error(__LINE__,__FILE__,"Error Creating VBuffer");

	//generate the tilemap vertices

	s3DVertex *verts = new s3DVertex[m_NumVertices];

	int cury = 0;
	int curx = 0;
	for( cury = 0; cury < m_NumYTiles+1; cury++)
	{
		for( curx = 0; curx < m_NumXTiles+1; curx++)
		{
			verts[cury*curx].diffuse = D3DCOLOR_XRGB(255,100,255);
			verts[cury*curx].u = (1/m_TileSet->GetWidth())*m_TileSet->GetTileWidth();
			verts[cury*curx].v = (1/m_TileSet->GetHeight())*m_TileSet->GetTileHeight();
			verts[cury*curx].x = curx * m_TileSet->GetTileWidth();
			verts[cury*curx].y = cury * m_TileSet->GetTileHeight();
			verts[cury*curx].z = 0.5f;
		}
	}

	if(!m_pVBuffer->Set(0,m_NumVertices,verts)) g_Log.Error(__LINE__,__FILE__,"Error setting vertices");


	//create the index buffer

	if(m_pIBuffer)
	{
		m_pIBuffer->Free();
	}
	else
	{
		m_pIBuffer = new CIndexBuffer();
	}

	if(!m_pIBuffer->Create(m_NumIndices)) g_Log.Error(__LINE__,__FILE__,"Creating index buffer");
	
	//generate the indices

	WORD * indices = new WORD[m_NumIndices];

	int curIndex = 0;

	g_Log.Print("Number of X Tiles:%d Number of Y Tiles:%d", m_NumXTiles,m_NumYTiles);

	cury = 0;
	curx = 0;
	//generate the indices uh oh..

	for( cury = 0; cury < m_NumYTiles; cury++)
	{
		for( curx = 0; curx < m_NumXTiles; curx++)
		{
			int topLeft = ((m_NumXTiles+1)*cury)+curx;
			int bottomLeft = topLeft+(m_NumXTiles+1);

			g_Log.Print("Current X = %d \n Current Y = %d", curx,cury);
			g_Log.Print("Bottom Left = %d \n Top Left = %d", bottomLeft,topLeft);

			//left triangle

			indices[curIndex++] = topLeft; //top left

			indices[curIndex++] = bottomLeft; //bottom left

			indices[curIndex++] = topLeft+1; //top right


			//right triangle

			indices[curIndex++] = topLeft+1; //top right

			indices[curIndex++] = bottomLeft; //bottom left

			indices[curIndex++] = bottomLeft+1; //bottom right

		}
	}

	m_pIBuffer->Set(indices);

	return 0;
}
  

  

int CTileMap::Draw(int OffsetX, int OffsetY)
{
	D3DXMATRIX matTrans;
	D3DXMatrixIdentity(&matTrans);

	D3DXMATRIX matRot;
	D3DXMatrixRotationZ(&matRot,D3DXToRadian(0));

	D3DXMATRIX matMult;
	D3DXMatrixMultiply(&matMult, &matTrans, &matRot);

	D3DXMATRIX matTransback;
	D3DXMatrixTranslation(&matTransback,-OffsetX,-OffsetY,0.5);

	D3DXMATRIX matFinal;
	D3DXMatrixMultiply(&matFinal, &matMult , & matTransback);
		
	g_Graphics->GetDeviceCOM()->SetTransform(D3DTS_WORLD,&matFinal);

	//set fvf

	m_Err = g_Graphics->GetDeviceCOM()->SetFVF(_3DVERTEX);
	if(m_Err != D3D_OK)
	{
		g_Log.DXError(__LINE__,__FILE__,m_Err);	
	}
	
	//set the stream source

	m_Err = g_Graphics->GetDeviceCOM()->SetStreamSource(0,m_pVBuffer->GetVertexBufferCOM(), 0, sizeof(s3DVertex));
	if(m_Err != D3D_OK)
	{
		g_Log.DXError(__LINE__,__FILE__,m_Err);	
	}

	//set the indices

	m_Err = g_Graphics->GetDeviceCOM()->SetTexture(0,m_TileSet->GetTiles());
	if(m_Err != D3D_OK)
	{
		g_Log.DXError(__LINE__,__FILE__,m_Err);	
	}

	//set the indices

	m_Err = g_Graphics->GetDeviceCOM()->SetIndices(m_pIBuffer->GetIndicesCOM());
	if(m_Err != D3D_OK)
	{
		g_Log.DXError(__LINE__,__FILE__,m_Err);	
	}

	//draw the primitive

	m_Err = g_Graphics->GetDeviceCOM()->DrawIndexedPrimitive(D3DPT_TRIANGLELIST,0,0,m_NumVertices,0,m_NumPolygons);
	if(m_Err != D3D_OK)
	{
		g_Log.DXError(__LINE__,__FILE__,m_Err);	
	}

	return 0;
}