/*
TEXTURES.C

	Copyright (C) 1991-2001 and beyond by Bungie Studios, Inc.
	and the "Aleph One" developers.
 
	This program 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 2 of the License, or
	(at your option) any later version.

	This program 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.

	This license is contained in the file "COPYING",
	which is included with this source code; it is available online at
	http://www.gnu.org/licenses/gpl.html

Monday, August 23, 1993 1:47:25 PM

Friday, May 13, 1994 1:56:03 PM
	precalculate_bitmap_row_addresses() now handles the new RLE shapes, added remap_bitmap().

Feb. 4, 2000 (Loren Petrich):
	Changed halt() to assert(false) for better debugging
*/

#include "cseries.h"
#include "textures.h"

#ifdef env68k
#pragma segment render
#endif

#define MARATHON2

/* ---------- code */

pixel8 *calculate_bitmap_origin(
	struct bitmap_definition *bitmap)
{
	pixel8 *origin;
	
	origin= (pixel8 *) (((byte *)bitmap) + sizeof(struct bitmap_definition));
	if (bitmap->flags&_COLUMN_ORDER_BIT)
	{
		origin+= bitmap->width*sizeof(pixel8 *);
	}
	else
	{
		origin+= bitmap->height*sizeof(pixel8 *);
	}
	
	return origin;
}

void remap_bitmap(
	struct bitmap_definition *bitmap,
	pixel8 *table)
{
	short row, rows, columns;
	
	rows= (bitmap->flags&_COLUMN_ORDER_BIT) ? bitmap->width : bitmap->height;
	columns= (bitmap->flags&_COLUMN_ORDER_BIT) ? bitmap->height : bitmap->width;

	if (bitmap->bytes_per_row!=NONE)
	{
		for (row=0;row<rows;++row)
		{
			map_bytes(bitmap->row_addresses[row], table, sizeof(pixel8)*columns);
		}
	}
	else
	{
#ifdef MARATHON1
		short run_count;
		pixel8 *pixels;
		
		pixels= bitmap->row_addresses[0];
		for (row= 0; row<rows; ++row)
		{
			// CB: this needs to be corrected to work properly on little-endian machines
			while (run_count= *((short*)pixels)++)
			{
				if (run_count>0)
				{
					map_bytes(pixels, table, run_count);
					pixels+= run_count;
				}
			}
		}
#endif

#ifdef MARATHON2
		pixel8 *pixels;
		
		pixels= bitmap->row_addresses[0];
		for (row= 0; row<rows; ++row)
		{
			// CB: first/last are stored in big-endian order
			uint16 first = *pixels++ << 8;
			first |= *pixels++;
			uint16 last = *pixels++ << 8;
			last |= *pixels++;
			map_bytes(pixels, table, last-first);
			pixels+= last-first;
		}
#endif
	}
;}

/* must initialize bytes_per_row, height and row_address[0] */
void precalculate_bitmap_row_addresses(
	struct bitmap_definition *bitmap)
{
	short row, rows, bytes_per_row;
	pixel8 *row_address, **table;

	rows= (bitmap->flags&_COLUMN_ORDER_BIT) ? bitmap->width : bitmap->height;

	row_address= bitmap->row_addresses[0];
	table= bitmap->row_addresses;
	if ((bytes_per_row= bitmap->bytes_per_row)!=NONE)
	{
		for (row=0;row<rows;++row)
		{
			*table++= row_address;
			row_address+= bytes_per_row;
		}
	}
	else
	{
#ifdef MARATHON1
		for (row= 0; row<rows; ++row)
		{
			short run_count;
			*table++= row_address;

			// CB: this needs to be corrected to work properly on little-endian systems
			while (run_count= *((short*)row_address)++)
			{
				if (run_count>0) row_address+= run_count;
			}
		}
#endif

#ifdef MARATHON2
		for (row= 0; row<rows; ++row)
		{
			*table++= row_address;
			
			// CB: first/last are stored in big-endian order
			uint16 first = *row_address++ << 8;
			first |= *row_address++;
			uint16 last = *row_address++ << 8;
			last |= *row_address++;
			row_address+= last-first;
		}
#endif
	}
}

void map_bytes(
	register byte *buffer,
	register byte *table,
	register long size)
{
	while ((size-=1)>=0)
	{
		*buffer= table[*buffer];
		buffer+= 1;
	}
}
