/*
===========================================================================

IcedTech GPL Source Code

Copyright (C) 2019 Real Vector Math Studios(Justin Marshall).
Copyright (C) 1993-2012 id Software LLC, a ZeniMax Media company. 

This file is part of the IcedTech GPL Source Code ("IcedTech GPL Source Code").  

IcedTech GPL Source Code is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

IcedTech GPL Source Code is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with IcedTech GPL Source Code.  If not, see <http://www.gnu.org/licenses/>.

In addition, the IcedTech GPL Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the IcedTech GPL Source Code.  If not, please request a copy in writing from id Software at the address below.

If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.

===========================================================================
*/

struct rvmMegaTextureSourceFile_t
{
	rvmMegaTextureSourceFile_t()
	{
		scratch = nullptr;
		scratch_position = 0;
		file = nullptr;
	}
	~rvmMegaTextureSourceFile_t()
	{
		if (scratch)
		{
			delete scratch;
			scratch = nullptr;
		}
		if (file)
		{
			fileSystem->CloseFile(file);
			file = nullptr;
		}

		scratch_position = 0;
	}

	void AllocScratch(int len)
	{
		scratch = new byte[len];
		scratch_position = 0;
	}

	void ResetScratch()
	{
		scratch_position = 0;
	}

	byte ReadByte()
	{
		return scratch[scratch_position++];
	}

	idFile *file;
	int		columns;
	int     rows;
	int     fileSize;
	int numBytes;
	byte *scratch;
	int scratch_position;
	
	TargaHeader	targa_header;
};

class idTextureTile {
public:
	int		x, y;
};

static const int TILE_PER_LEVEL = 4;
static const int MAX_MEGA_CHANNELS = 3;		// normal, diffuse, specular
static const int MAX_LEVELS = 12;
static const int MAX_LEVEL_WIDTH = 1024;
static const int TILE_SIZE = MAX_LEVEL_WIDTH / TILE_PER_LEVEL;

class	idMegaTexture;
class   rvmMegaTextureFile;

class idTextureLevel {
public:
	rvmMegaTextureFile	*mega;

	int				tileOffset;
	int				tilesWide;
	int				tilesHigh;

	idImage			*image;
	idTextureTile	tileMap[TILE_PER_LEVEL][TILE_PER_LEVEL];

	float			parms[4];

	void			UpdateForCenter( float center[2] );
	void			UpdateTile( int localX, int localY, int globalX, int globalY );
	void			Invalidate();
};

typedef struct {
	int		tileSize;
	int		tilesWide;
	int		tilesHigh;
} megaTextureHeader_t;

// jmarshall
class rvmMegaTextureFile {
public:
	~rvmMegaTextureFile();

	// Loads in a mega texture file.
	static rvmMegaTextureFile *LoadMegaTextureFile(const char *name);

	void UpdateForCenter(float	texCenter[2]);
	void BindForViewOrigin(const idVec3 viewOrigin); // binds images and sets program parameters
	void Invalidate(void);

	void ReadTile(byte *tileBuffer, int tileNum);
public:
	int				numLevels;
	idTextureLevel	levels[MAX_LEVELS];				// 0 is the highest resolution
	megaTextureHeader_t	header;
private:
	rvmMegaTextureFile();

	idFile			*fileHandle;
};
// jmarshall end

class idMegaTexture {
public:
	idMegaTexture();
	~idMegaTexture();

	bool	InitFromMegaFile( const char *fileBase );
	void	SetMappingForSurface( const srfTriangles_t *tri );	// analyzes xyz and st to create a mapping
	void	BindForViewOrigin( const idVec3 origin );	// binds images and sets program parameters
	void	Unbind();								// removes texture bindings

	static	void MakeMegaTexture_f( const idCmdArgs &args );
private:
	friend class idTextureLevel;
// jmarshall
	friend class rvmMegaTextureFile;
// jmarshall end
	void	SetViewOrigin( const idVec3 origin );
	static void	GenerateMegaMipMaps( megaTextureHeader_t *header, idFile *file );
	static void	GenerateMegaPreview( const char *fileName );
// jmarshall
	static void ProcessTGABlock(rvmMegaTextureSourceFile_t *file, byte *targa_rgba, TargaHeader	&targa_header, int columns, int rows, int scale);
	static idFile *LoadTGA(const char *name, TargaHeader &targa_header, int	&columns, int &rows, int &fileSize, int &numBytes);
// jmarshall end

	const srfTriangles_t *currentTriMapping;

	idVec3			currentViewOrigin;
// jmarshall
//	float			localViewToTextureCenter[2][4];
	idBounds		surfaceBounds;
// jmarshall end

// jmarshall
	idImage			*megaNormalMaskImage;
// jmarshall end

// jmarshall
	rvmMegaTextureFile	*albedoLitMegaTextureFile;
// jmarshall end


	static idCVar	r_megaTextureLevel;
	static idCVar	r_showMegaTexture;
	static idCVar	r_showMegaTextureLabels;
	static idCVar	r_skipMegaTexture;
	static idCVar	r_terrainScale;

// jmarshall
	static idCVar	r_megatexture_ambient;
// jmarshall end
};