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/*

 * OpenTyrian: A modern cross-platform port of Tyrian

 * Copyright (C) 2007-2009  The OpenTyrian Development Team

 *

 * 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.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

 */

#include "palette.h"

#include "file.h"

#include "nortsong.h"

#include "opentyr.h"

#include "video.h"

#include 

static Uint32 rgb_to_yuv( int r, int g, int b );

#define PALETTE_COUNT 23

Palette palettes[PALETTE_COUNT];

int palette_count;

static Palette palette;

Uint32 rgb_palette[256], yuv_palette[256];

Palette colors;

void JE_loadPals( void )

{

	FILE *f = dir_fopen_die(data_dir(), "palette.dat", "rb");

	palette_count = ftell_eof(f) / (256 * 3);

	assert(palette_count == PALETTE_COUNT);

	for (int p = 0; p < palette_count; ++p)

	{

		for (int i = 0; i < 256; ++i)

		{

			// The VGA hardware palette used only 6 bits per component, so the values need to be rescaled to

			// 8 bits. The naive way to do this is to simply do (c << 2), padding it with 0's, however this

			// makes the maximum value 252 instead of the proper 255. A trick to fix this is to use the upper 2

			// bits of the original value instead. This ensures that the value goes to 255 as the original goes

			// to 63.

			int c = getc(f);

			palettes[p][i].r = (c << 2) | (c >> 4);

			c = getc(f);

			palettes[p][i].g = (c << 2) | (c >> 4);

			c = getc(f);

			palettes[p][i].b = (c << 2) | (c >> 4);

		}

	}

	fclose(f);

}

void set_palette( Palette colors, unsigned int first_color, unsigned int last_color )

{

	SDL_Surface *const surface = SDL_GetVideoSurface();

	const uint bpp = surface->format->BitsPerPixel;

	for (uint i = first_color; i <= last_color; ++i)

	{

		palette[i] = colors[i];

		if (bpp != 8)

		{

			rgb_palette[i] = SDL_MapRGB(surface->format, palette[i].r, palette[i].g, palette[i].b);

			yuv_palette[i] = rgb_to_yuv(palette[i].r, palette[i].g, palette[i].b);

		}

	}

	if (bpp == 8)

		SDL_SetColors(surface, palette, first_color, last_color - first_color + 1);

}

void set_colors( SDL_Color color, unsigned int first_color, unsigned int last_color )

{

	SDL_Surface *const surface = SDL_GetVideoSurface();

	const uint bpp = surface->format->BitsPerPixel;

	for (uint i = first_color; i <= last_color; ++i)

	{

		palette[i] = color;

		if (bpp != 8)

		{

			rgb_palette[i] = SDL_MapRGB(surface->format, palette[i].r, palette[i].g, palette[i].b);

			yuv_palette[i] = rgb_to_yuv(palette[i].r, palette[i].g, palette[i].b);

		}

	}

	if (bpp == 8)

		SDL_SetColors(surface, palette, first_color, last_color - first_color + 1);

}

void init_step_fade_palette( int diff[256][3], Palette colors, unsigned int first_color, unsigned int last_color )

{

	for (unsigned int i = first_color; i <= last_color; i++)

	{

		diff[i][0] = (int)colors[i].r - palette[i].r;

		diff[i][1] = (int)colors[i].g - palette[i].g;

		diff[i][2] = (int)colors[i].b - palette[i].b;

	}

}

void init_step_fade_solid( int diff[256][3], SDL_Color color, unsigned int first_color, unsigned int last_color )

{

	for (unsigned int i = first_color; i <= last_color; i++)

	{

		diff[i][0] = (int)color.r - palette[i].r;

		diff[i][1] = (int)color.g - palette[i].g;

		diff[i][2] = (int)color.b - palette[i].b;

	}

}

void step_fade_palette( int diff[256][3], int steps, unsigned int first_color, unsigned int last_color )

{

	assert(steps > 0);

	SDL_Surface *const surface = SDL_GetVideoSurface();

	const uint bpp = surface->format->BitsPerPixel;

	for (unsigned int i = first_color; i <= last_color; i++)

	{

		int delta[3] = { diff[i][0] / steps, diff[i][1] / steps, diff[i][2] / steps };

		diff[i][0] -= delta[0];

		diff[i][1] -= delta[1];

		diff[i][2] -= delta[2];

		palette[i].r += delta[0];

		palette[i].g += delta[1];

		palette[i].b += delta[2];

		if (bpp != 8)

		{

			rgb_palette[i] = SDL_MapRGB(surface->format, palette[i].r, palette[i].g, palette[i].b);

			yuv_palette[i] = rgb_to_yuv(palette[i].r, palette[i].g, palette[i].b);

		}

	}

	if (bpp == 8)

		SDL_SetColors(surface, palette, 0, 256);

}

void fade_palette( Palette colors, int steps, unsigned int first_color, unsigned int last_color )

{

	assert(steps > 0);

	SDL_Surface *const surface = SDL_GetVideoSurface();

	const uint bpp = surface->format->BitsPerPixel;

	static int diff[256][3];

	init_step_fade_palette(diff, colors, first_color, last_color);

	for (; steps > 0; steps--)

	{

		setdelay(1);

		step_fade_palette(diff, steps, first_color, last_color);

		if (bpp != 8)

			JE_showVGA();

		wait_delay();

	}

}

void fade_solid( SDL_Color color, int steps, unsigned int first_color, unsigned int last_color )

{

	assert(steps > 0);

	SDL_Surface *const surface = SDL_GetVideoSurface();

	const uint bpp = surface->format->BitsPerPixel;

	static int diff[256][3];

	init_step_fade_solid(diff, color, first_color, last_color);

	for (; steps > 0; steps--)

	{

		setdelay(1);

		step_fade_palette(diff, steps, first_color, last_color);

		if (bpp != 8)

			JE_showVGA();

		wait_delay();

	}

}

void fade_black( int steps )

{

	SDL_Color black = { 0, 0, 0 };

	fade_solid(black, steps, 0, 255);

}

void fade_white( int steps )

{

	SDL_Color white = { 255, 255, 255 };

	fade_solid(white, steps, 0, 255);

}

static Uint32 rgb_to_yuv( int r, int g, int b )

{

	int y = (r + g + b) >> 2,

	    u = 128 + ((r - b) >> 2),

	    v = 128 + ((-r + 2 * g - b) >> 3);

	return (y << 16) + (u << 8) + v;

}