/*
THE COMPUTER CODE CONTAINED HEREIN IS THE SOLE PROPERTY OF PARALLAX
SOFTWARE CORPORATION ("PARALLAX").  PARALLAX, IN DISTRIBUTING THE CODE TO
END-USERS, AND SUBJECT TO ALL OF THE TERMS AND CONDITIONS HEREIN, GRANTS A
ROYALTY-FREE, PERPETUAL LICENSE TO SUCH END-USERS FOR USE BY SUCH END-USERS
IN USING, DISPLAYING,  AND CREATING DERIVATIVE WORKS THEREOF, SO LONG AS
SUCH USE, DISPLAY OR CREATION IS FOR NON-COMMERCIAL, ROYALTY OR REVENUE
FREE PURPOSES.  IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
CONTAINED HEREIN FOR REVENUE-BEARING PURPOSES.  THE END-USER UNDERSTANDS
AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.  
COPYRIGHT 1993-1998 PARALLAX SOFTWARE CORPORATION.  ALL RIGHTS RESERVED.
*/

/*
 *
 * Graphical routines for setting the palette
 *
 */

#include <stdlib.h>
#include <stdio.h>

#include "pstypes.h"
#include "u_mem.h"
#include "gr.h"
#include "grdef.h"
#include "cfile.h"
#include "error.h"
#include "fix.h"

extern int gr_installed;

ubyte gr_palette[256*3];
ubyte gr_current_pal[256*3];
ubyte gr_fade_table[256*34];

ubyte gr_palette_gamma = 0;
int gr_palette_gamma_param = 0;

extern void gr_palette_load( ubyte * pal );

void gr_palette_set_gamma( int gamma )
{
	if ( gamma < 0 ) gamma = 0;
        if ( gamma > 16 ) gamma = 16;      //was 8

	if (gr_palette_gamma_param != gamma )	{
		gr_palette_gamma_param = gamma;
		gr_palette_gamma = gamma;
		gr_palette_load( gr_palette );
	}
}

int gr_palette_get_gamma()
{
	return gr_palette_gamma_param;
}


void gr_use_palette_table( char * filename )
{
	CFILE *fp;
	int i,fsize;

	fp = cfopen( filename, "rb" );
	if ( fp==NULL)
		Error("Can't open palette file <%s>",filename);

	fsize	= cfilelength( fp );
	Assert( fsize == 9472 );
	cfread( gr_palette, 256*3, 1, fp );
	cfread( gr_fade_table, 256*34, 1, fp );
	cfclose(fp);

	// This is the TRANSPARENCY COLOR
	for (i=0; i<GR_FADE_LEVELS; i++ )	{
		gr_fade_table[i*256+255] = 255;
	}
}

#define SQUARE(x) ((x)*(x))

#define	MAX_COMPUTED_COLORS	32

int	Num_computed_colors=0;

typedef struct {
	ubyte	r,g,b,color_num;
} color_record;

color_record Computed_colors[MAX_COMPUTED_COLORS];

//	Add a computed color (by gr_find_closest_color) to list of computed colors in Computed_colors.
//	If list wasn't full already, increment Num_computed_colors.
//	If was full, replace a random one.
void add_computed_color(int r, int g, int b, int color_num)
{
	int	add_index;

	if (Num_computed_colors < MAX_COMPUTED_COLORS) {
		add_index = Num_computed_colors;
		Num_computed_colors++;
	} else
		add_index = (d_rand() * MAX_COMPUTED_COLORS) >> 15;

	Computed_colors[add_index].r = r;
	Computed_colors[add_index].g = g;
	Computed_colors[add_index].b = b;
	Computed_colors[add_index].color_num = color_num;
}

void init_computed_colors(void)
{
	int	i;

	for (i=0; i<MAX_COMPUTED_COLORS; i++)
		Computed_colors[i].r = 255;		//	Make impossible to match.
}

int gr_find_closest_color( int r, int g, int b )
{
	int i, j;
	int best_value, best_index, value;

	if (Num_computed_colors == 0)
		init_computed_colors();

	//	If we've already computed this color, return it!
	for (i=0; i<Num_computed_colors; i++)
		if (r == Computed_colors[i].r)
			if (g == Computed_colors[i].g)
				if (b == Computed_colors[i].b) {
					if (i > 4) {
						color_record	trec;
						trec = Computed_colors[i-1];
						Computed_colors[i-1] = Computed_colors[i];
						Computed_colors[i] = trec;
						return Computed_colors[i-1].color_num;
					}
					return Computed_colors[i].color_num;
				}

//	r &= 63;
//	g &= 63;
//	b &= 63;

	best_value = SQUARE(r-gr_palette[0])+SQUARE(g-gr_palette[1])+SQUARE(b-gr_palette[2]);
	best_index = 0;
	if (best_value==0) {
		add_computed_color(r, g, b, best_index);
 		return best_index;
	}
	j=0;
	// only go to 255, 'cause we dont want to check the transparent color.
	for (i=1; i<254; i++ )	{
		j += 3;
		value = SQUARE(r-gr_palette[j])+SQUARE(g-gr_palette[j+1])+SQUARE(b-gr_palette[j+2]);
		if ( value < best_value )	{
			if (value==0) {
				add_computed_color(r, g, b, i);
				return i;
			}
			best_value = value;
			best_index = i;
		}
	}
	add_computed_color(r, g, b, best_index);
	return best_index;
}

int gr_find_closest_color_15bpp( int rgb )
{
	return gr_find_closest_color( ((rgb>>10)&31)*2, ((rgb>>5)&31)*2, (rgb&31)*2 );
}


int gr_find_closest_color_current( int r, int g, int b )
{
	int i, j;
	int best_value, best_index, value;

//	r &= 63;
//	g &= 63;
//	b &= 63;

	best_value = SQUARE(r-gr_current_pal[0])+SQUARE(g-gr_current_pal[1])+SQUARE(b-gr_current_pal[2]);
	best_index = 0;
	if (best_value==0)
 		return best_index;

	j=0;
	// only go to 255, 'cause we dont want to check the transparent color.
	for (i=1; i<254; i++ )	{
		j += 3;
		value = SQUARE(r-gr_current_pal[j])+SQUARE(g-gr_current_pal[j+1])+SQUARE(b-gr_current_pal[j+2]);
		if ( value < best_value )	{
			if (value==0)
				return i;
			best_value = value;
			best_index = i;
		}
	}
	return best_index;
}

void gr_make_cthru_table(ubyte * table, ubyte r, ubyte g, ubyte b )
{
	int i;
	ubyte r1, g1, b1;

	for (i=0; i<256; i++ )	{
		r1 = gr_palette[i*3+0] + r;
		if ( r1 > 63 ) r1 = 63;
		g1 = gr_palette[i*3+1] + g;
		if ( g1 > 63 ) g1 = 63;
		b1 = gr_palette[i*3+2] + b;
		if ( b1 > 63 ) b1 = 63;
		table[i] = gr_find_closest_color( r1, g1, b1 );
	}
}