// Emacs style mode select   -*- C++ -*- 
//-----------------------------------------------------------------------------
//
// $Id:$
//
// Copyright (C) 1993-1996 by id Software, Inc.
//
// This source is available for distribution and/or modification
// only under the terms of the DOOM Source Code License as
// published by id Software. All rights reserved.
//
// The source is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
// for more details.
//
// $Log:$
//
// Revision 1.3  1997/01/29 20:10
// DESCRIPTION:
//	Preparation of data for rendering,
//	generation of lookups, caching, retrieval by name.
//
//-----------------------------------------------------------------------------


static const char
rcsid[] = "$Id: r_data.c,v 1.4 1997/02/03 16:47:55 b1 Exp $";

#include "i_system.h"
#include "z_zone.h"

#include "m_swap.h"

#include "w_wad.h"

#include "doomdef.h"
#include "r_local.h"
#include "p_local.h"

#include "doomstat.h"
#include "r_sky.h"

#ifdef LINUX
#include  <alloca.h>
#endif

#define alloca malloc


#include "r_data.h"

char MsgText[256];
void WriteDebug(char *);

//
// Graphics.
// DOOM graphics for walls and sprites
// is stored in vertical runs of opaque pixels (posts).
// A column is composed of zero or more posts,
// a patch or sprite is composed of zero or more columns.
// 



//
// Texture definition.
// Each texture is composed of one or more patches,
// with patches being lumps stored in the WAD.
// The lumps are referenced by number, and patched
// into the rectangular texture space using origin
// and possibly other attributes.
//
typedef struct
{
    short	originx;
    short	originy;
    short	patch;
    short	stepdir;
    short	colormap;
} mappatch_t;


//
// Texture definition.
// A DOOM wall texture is a list of patches
// which are to be combined in a predefined order.
//
typedef struct
{
    char		name[8];
    boolean		masked;	
    short		width;
    short		height;
    void		**columndirectory;	// OBSOLETE
    short		patchcount;
    mappatch_t	patches[1];
} maptexture_t;


// A single patch from a texture definition,
//  basically a rectangular area within
//  the texture rectangle.
typedef struct
{
    // Block origin (allways UL),
    // which has allready accounted
    // for the internal origin of the patch.
    int		originx;	
    int		originy;
    int		patch;
} texpatch_t;


// A maptexturedef_t describes a rectangular texture,
//  which is composed of one or more mappatch_t structures
//  that arrange graphic patches.
typedef struct
{
    // Keep name for switch changing, etc.
    char	name[8];		
    short	width;
    short	height;
    
    // All the patches[patchcount]
    //  are drawn back to front into the cached texture.
    short	patchcount;
    texpatch_t	patches[1];		
    
} texture_t;



int		firstflat;
int		lastflat;
int		numflats;

int		firstpatch;
int		lastpatch;
int		numpatches;

int		firstspritelump;
int		lastspritelump;
int		numspritelumps;

int		numtextures;
texture_t**	textures;


int*			texturewidthmask;
// needed for texture pegging
fixed_t*		textureheight;		
int*			texturecompositesize;
short**			texturecolumnlump;
unsigned short**	texturecolumnofs;
byte**			texturecomposite;

// for global animation
int*		flattranslation;
int*		texturetranslation;

// needed for pre rendering
fixed_t*	spritewidth;	
fixed_t*	spriteoffset;
fixed_t*	spritetopoffset;

lighttable_t	*colormaps;


//
// MAPTEXTURE_T CACHING
// When a texture is first needed,
//  it counts the number of composite columns
//  required in the texture and allocates space
//  for a column directory and any new columns.
// The directory will simply point inside other patches
//  if there is only one patch in a given column,
//  but any columns with multiple patches
//  will have new column_ts generated.
//



//
// R_DrawColumnInCache
// Clip and draw a column
//  from a patch into a cached post.
//
void
R_DrawColumnInCache
( column_t*	patch,
  byte*		cache,
  int		originy,
  int		cacheheight )
{
    int		count;
    int		position;
    byte*	source;
    byte*	dest;
	
    dest = (byte *)cache + 3;
	
    while (patch->topdelta != 0xff)
    {
	source = (byte *)patch + 3;
	count = patch->length;
	position = originy + patch->topdelta;

	if (position < 0)
	{
	    count += position;
	    position = 0;
	}

	if (position + count > cacheheight)
	    count = cacheheight - position;

	if (count > 0)
	    memcpy (cache + position, source, count);
		
	patch = (column_t *)(  (byte *)patch + patch->length + 4); 
    }
}



//
// R_GenerateComposite
// Using the texture definition,
//  the composite texture is created from the patches,
//  and each column is cached.
//
void R_GenerateComposite (int texnum)
{
    byte*		block;
    texture_t*		texture;
    texpatch_t*		patch;	
    patch_t*		realpatch;
    int			x;
    int			x1;
    int			x2;
    int			i;
    column_t*		patchcol;
    short*		collump;
    unsigned short*	colofs;
	
    texture = textures[texnum];

    block = Z_Malloc (texturecompositesize[texnum],
		      PU_STATIC, 
		      &texturecomposite[texnum]);	

    collump = texturecolumnlump[texnum];
    colofs = texturecolumnofs[texnum];
    
    // Composite the columns together.
    patch = texture->patches;
		
    for (i=0 , patch = texture->patches;
	 i<texture->patchcount;
	 i++, patch++)
    {
	realpatch = W_CacheLumpNum (patch->patch, PU_CACHE);
	x1 = patch->originx;
	x2 = x1 + SHORT(realpatch->width);

	if (x1<0)
	    x = 0;
	else
	    x = x1;
	
	if (x2 > texture->width)
	    x2 = texture->width;

	for ( ; x<x2 ; x++)
	{
	    // Column does not have multiple patches?
	    if (collump[x] >= 0)
		continue;
	    
	    patchcol = (column_t *)((byte *)realpatch
				    + LONG(realpatch->columnofs[x-x1]));
	    R_DrawColumnInCache (patchcol,
				 block + colofs[x],
				 patch->originy,
				 texture->height);
	}
						
    }

    // Now that the texture has been built in column cache,
    //  it is purgable from zone memory.
    Z_ChangeTag (block, PU_CACHE);
}



//
// R_GenerateLookup
//
void R_GenerateLookup (int texnum)
{
    texture_t*		texture;
    byte*		patchcount;	// patchcount[texture->width]
    texpatch_t*		patch;	
    patch_t*		realpatch;
    int			x;
    int			x1;
    int			x2;
    int			i;
    short*		collump;
    unsigned short*	colofs;
	
    texture = textures[texnum];

    // Composited texture not created yet.
    texturecomposite[texnum] = 0;
    
    texturecompositesize[texnum] = 0;
    collump = texturecolumnlump[texnum];
    colofs = texturecolumnofs[texnum];
    
    // Now count the number of columns
    //  that are covered by more than one patch.
    // Fill in the lump / offset, so columns
    //  with only a single patch are all done.
    patchcount = (byte *)alloca (texture->width);
    memset (patchcount, 0, texture->width);
    patch = texture->patches;
		
    for (i=0 , patch = texture->patches;
	 i<texture->patchcount;
	 i++, patch++)
    {
	realpatch = W_CacheLumpNum (patch->patch, PU_CACHE);
	x1 = patch->originx;
	x2 = x1 + SHORT(realpatch->width);
	
	if (x1 < 0)
	    x = 0;
	else
	    x = x1;

	if (x2 > texture->width)
	    x2 = texture->width;
	for ( ; x<x2 ; x++)
	{
	    patchcount[x]++;
	    collump[x] = patch->patch;
	    colofs[x] = LONG(realpatch->columnofs[x-x1])+3;
	}
    }
	
    for (x=0 ; x<texture->width ; x++)
    {
	if (!patchcount[x])
	{
	    sprintf (MsgText,"R_GenerateLookup: column without a patch (%s)\n",
		    texture->name);
        WriteDebug(MsgText);
	    return;
	}
	// I_Error ("R_GenerateLookup: column without a patch");
	
	if (patchcount[x] > 1)
	{
	    // Use the cached block.
	    collump[x] = -1;	
	    colofs[x] = texturecompositesize[texnum];
	    
	    if (texturecompositesize[texnum] > 0x10000-texture->height)
	    {
		I_Error ("R_GenerateLookup: texture %i is >64k",
			 texnum);
	    }
	    
	    texturecompositesize[texnum] += texture->height;
	}
    }	
}




//
// R_GetColumn
//
byte*
R_GetColumn
( int		tex,
  int		col )
{
    int		lump;
    int		ofs;
	
    col &= texturewidthmask[tex];
    lump = texturecolumnlump[tex][col];
    ofs = texturecolumnofs[tex][col];
    
    if (lump > 0)
	return (byte *)W_CacheLumpNum(lump,PU_CACHE)+ofs;

    if (!texturecomposite[tex])
	R_GenerateComposite (tex);

    return texturecomposite[tex] + ofs;
}




//
// R_InitTextures
// Initializes the texture list
//  with the textures from the world map.
//
void R_InitTextures (void)
{
    maptexture_t*	mtexture;
    texture_t*		texture;
    mappatch_t*		mpatch;
    texpatch_t*		patch;

    int			i;
    int			j;

    int*		maptex;
    int*		maptex2;
    int*		maptex1;
    
    char		name[9];
    char*		names;
    char*		name_p;
    
    int*		patchlookup;
    
    int			totalwidth;
    int			nummappatches;