tf2/tf2_src/vguimatsurface/FontTextureCache.h

//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose: 
//
// $NoKeywords: $
//=============================================================================//

#ifndef FONTTEXTURECACHE_H
#define FONTTEXTURECACHE_H
#ifdef _WIN32
#pragma once
#endif

#include "vgui_surfacelib/FontManager.h"
#include "utlrbtree.h"
#include <vgui/ISurface.h>
#include "utlmap.h"

class ITexture;

//-----------------------------------------------------------------------------
// Purpose: manages texture memory for unicode fonts in vgui
//-----------------------------------------------------------------------------
class CFontTextureCache
{
public:
	CFontTextureCache();
	~CFontTextureCache();

	// returns a texture ID and a pointer to an array of 4 texture coords for the given character & font
	// generates+uploads more texture if necessary
	bool GetTextureForChar( vgui::HFont font, vgui::FontDrawType_t type, wchar_t wch, int *textureID, float **texCoords );

	// for each character in an array (not assumed to be a NULL-terminated string), returns a
	// texture ID and a pointer to an array of 4 texture coords for the given character & font
	// generates+uploads more texture if necessary
	bool GetTextureForChars( vgui::HFont font, vgui::FontDrawType_t type, const wchar_t *wch, int *textureID, float **texCoords, int numChars = 1 );

	// clears the cache
	void Clear();

private:
	// NOTE: If you change this, change s_pFontPageSize
	enum
	{
		FONT_PAGE_SIZE_16,
		FONT_PAGE_SIZE_32,
		FONT_PAGE_SIZE_64,
		FONT_PAGE_SIZE_128,
		FONT_PAGE_SIZE_256,
		FONT_PAGE_SIZE_COUNT,
	};

	// a single character in the cache
	typedef unsigned short HCacheEntry;
	struct CacheEntry_t
	{
		vgui::HFont		font;
		wchar_t			wch;
		unsigned char	page;
		float			texCoords[4];

		// doubly-linked list for use in the LRU
		HCacheEntry		nextEntry;
		HCacheEntry		prevEntry;
	};
	
	// a single texture page
	struct Page_t
	{
		short textureID[vgui::FONT_DRAW_TYPE_COUNT];
		short maxFontHeight;
		short tallestCharOnLine;
		short wide, tall;	// total size of the page
		short nextX, nextY;	// position to draw any new character positions
	};

	// allocates a new page for a given character
	bool AllocatePageForChar(int charWide, int charTall, int &pageIndex, int &drawX, int &drawY, int &twide, int &ttall);

	// Creates font materials
	void CreateFontMaterials( Page_t &page, ITexture *pFontTexture, bool bitmapFont = false );

	// Computes the page size given a character height
	int ComputePageType( int charTall ) const;

	static bool CacheEntryLessFunc(const CacheEntry_t &lhs, const CacheEntry_t &rhs);

	CUtlRBTree<CacheEntry_t, HCacheEntry>	m_CharCache;

	// cache
	typedef CUtlVector<Page_t>	FontPageList_t;
	FontPageList_t				m_PageList;
	
	int			m_pCurrPage[FONT_PAGE_SIZE_COUNT];
	HCacheEntry	m_LRUListHeadIndex;
	static int	s_pFontPageSize[FONT_PAGE_SIZE_COUNT];
	CUtlMap< vgui::HFont, Page_t >	m_FontPages;
};


#endif // FONTTEXTURECACHE_H