/* Copyright (C) 1994-2003 Revolution Software Ltd
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * $Header: /cvsroot/scummvm/scummvm/bs2/driver/palette.cpp,v 1.13 2003/08/27 07:01:05 eriktorbjorn Exp $
 */

//=============================================================================
//
//	Filename	:	palette.c
//	Created		:	22nd August 1996
//	By			:	P.R.Porter
//
//	Summary		:	This module holds the palette functions and the interface
//					to the directDraw palette.
//
//	Version	Date		By		Description
//	------- ---------	---		-----------------------------------------------
//	1.0		16-Sep-96	PRP		Currently holds the palette setting code.  Will
//								be modified so that the calling functions have
//								to use the correct palette format, and the
//								fading code will be added.
//
//	1.1		17-Sep-96	PRP		Removed utypes.h from include list.
//
//	1.2		03-Oct-96	PRP		Changed the palette format to RGBA 0-255.
//
//	1.3		04-Oct-96	PRP		No changes
//
//	1.4		04-Oct-96	PRP		Put direct path in for ddraw.h
//
//	1.5		08-Nov-96	PRP		Created a drivers copy of the palette so that
//								it can be restored at any time without the
//								game engine having to worry about things.
//								Currently, there is different code for setting
//								the palette in full screen and windowed mode
//								until I can get windowed mode working.
//
//	1.6		09-Nov-96	PRP		More work to get the palette to work propery
//								in windowed mode.
//
//	1.7		22-Nov-96	PRP		Made the whole of the palette available to 
//								the rest of the driver96 code.
//
//	1.8		25-Nov-96	PRP		Added a function to create a palette match
//								table from the current palette.
//
//	1.9		29-Nov-96	PRP		Made the QuickMatch function __inline for
//								speed - but didn't work.  Added functions
//								to fade the palette up and down.
//
//	1.10	05-Dec-96	PRP		Added a flag to BS2_SetPalette so that the palette
//								can be set immediately or later by the fade.
//
//	1.11	06-Dec-96	JEL		fadeStatus now initialised to 0
//
//	1.12	09-Dec-96	PRP		Function UpdatePaletteMatchTable() changed so
//								that the data can be part of another file.
//
//	1.13	10-Feb-97	PRP		Changed the direct draw error reporting calls.
//
//	1.14	11-Feb-97	PRP		Suspended the fade server if the direct draw
//								palette object does not exist.
//
//	1.15	17-Mar-97	PRP		Added RDFADE_BLACK as a return value so the
//								engine knows the state of the palette when
//								there is no fade.
//
//	1.16	17-Mar-97	PRP		Fixed driver bug which caused FadeUp to fail
//								becuase of the introduction of RDFADE_BLACK.
//
//	1.17	26-Jun-97	PRP		Added a function to darken the palette for pausing.
//
//	1.18	26-Jun-97	PRP		Forgot to return a value.
//
//	1.19	26-Jun-97	PRP		Forgot to set the palette - DOH!
//
//	1.20	26-Jun-97	PRP		Fixed undefined symbols bugs.
//
//	1.21	09-Jul-97	JEL		Fixed palette dimming - to unsigned rather than signed RGB values!
//
//	1.22	26-Jun-97	JEL		BS2_SetPalette now always sets colour 0 to black so doesn't need setting to black from game engine
//
//	1.23	10-Jul-97	JEL		Nothing changed but new version had to be booked in anyway.
//
//	1.24	10-Jul-97	JEL		BS2_SetPalette doesn't do that any more (see above)!
//
//	Functions
//	---------
//
//	--------------------------------------------------------------------------
//
//	void BS2_SetPalette(int32 startEntry, int32 noEntries, uint8 *colourTable)
//
//	Sets the palette from position startEntry for noEntries, to the data 
//	pointed to by colourTable.
//
//	--------------------------------------------------------------------------
//
//	void UpdatePaletteMatchTable(uint8 *data)
//
//	Uses the current palCopy to create a table of palette indeces which will
//	be searched later for a quick palette match, if data is NULL.  Otherwise
//	it uses the table passed in.
//
//	--------------------------------------------------------------------------
//
//	uint8 QuickMatch(uint8 r, uint8 g, uint8 b)
//
//	Returns the palette index of the closest matching colour in the palette
//	to these RGB values.
//
//	--------------------------------------------------------------------------
//
//	int32 FadeUp(float time)
//
//	Fades the palette up from black to the current palette in time.
//
//	--------------------------------------------------------------------------
//
//	int32 FadeDown(float time)
//
//	Fades the palette down to black from the current palette in time.
//
//	--------------------------------------------------------------------------
//
//	uint8 GetFadeStatus(void)
//
//	Returns the fade status which can be one of RDFADE_UP, RDFADE_DOWN or
//	RDFADE_NONE.
//
//=============================================================================

#include "stdafx.h"
#include <stdio.h>

#include "common/util.h"
#include "common/engine.h"
#include "d_draw.h"
#include "driver96.h"
#include "../sword2.h"

#define PALTABLESIZE 64 * 64 * 64

uint8 palCopy[256][4];
uint8 fadePalette[256][4];

uint8 paletteMatch[PALTABLESIZE];

uint8 fadeStatus = RDFADE_NONE;

static int32 fadeStartTime;
static int32 fadeTotalTime;

// --------------------------------------------------------------------------
// int32 RestorePalette(void)
//
// This function restores the palette, and should be called whenever the
// screen mode changes, or something like that.
// --------------------------------------------------------------------------

int32 RestorePalette(void) {
	g_system->set_palette((const byte *) palCopy, 0, 256);
	return RD_OK;
}

uint8 GetMatch(uint8 r, uint8 g, uint8 b) {
	int32 diff;
	int32 min;
	int16 diffred, diffgreen, diffblue;
	int16 i;
	uint8 minIndex;

	diffred = palCopy[0][0] - r;
	diffgreen = palCopy[0][1] - g;
	diffblue = palCopy[0][2] - b;

	diff = diffred * diffred + diffgreen * diffgreen + diffblue * diffblue;
	min = diff;
	minIndex = 0;
	if (diff > 0) {
		i = 1;
		while (i < 256)	{
			diffred = palCopy[i][0] - r;
			diffgreen = palCopy[i][1] - g;
			diffblue = palCopy[i][2] - b;

			diff = diffred * diffred + diffgreen * diffgreen + diffblue * diffblue;
			if (diff < min) {
				min = diff;
				minIndex = (uint8) i;
				if (min == 0)
					break;
			}
			i++;
		}
	}

	// Here, minIndex is the index of the matchpalette which is closest.
	return(minIndex);
}

// FIXME: Does this function really need to write to file?

int32 UpdatePaletteMatchTable(uint8 *data) {
	if (!data) {
		FILE *fp;
		int16 red, green, blue;
		uint8 *p;

		// Create palette match table
		p = &paletteMatch[0];
		for (red = 0; red < 256; red += 4) {
			for (green = 0; green < 256; green += 4) {
				for (blue = 0; blue < 256; blue += 4) {
					*p++ = GetMatch((uint8) red, (uint8) green, (uint8) blue);
				}
			}
		}

		// Write out palette match table
		fp = fopen("r11.rgb", "wb");
		if (fp == NULL)
			return(RDERR_INVALIDFILENAME);
		if (fwrite(paletteMatch, 1, 64*64*64, fp) != 64*64*64)
			return(RDERR_WRITEERROR);
		fclose(fp);
	} else {
		// Read table from file
		memcpy(paletteMatch, data, PALTABLESIZE);
	
/*
		FILE *fp;

		fp = fopen(filename, "rb");
		if (fp == NULL)
			return(RDERR_INVALIDFILENAME);
		if (fread(paletteMatch, 1, 64*64*64, fp) != 64*64*64)
			return(RDERR_READERROR);
		fclose(fp);
		return(RD_OK);
*/		
	}
	return RD_OK;
}

// FIXME: This used to be inlined - probably a good idea - but the
// linker complained when I tried to use it in sprite.cpp.

uint8 QuickMatch(uint8 r, uint8 g, uint8 b) {
	return paletteMatch[((int32) (r >> 2) << 12) + ((int32) (g >> 2) << 6) + (b >> 2)];
}

int32 BS2_SetPalette(int16 startEntry, int16 noEntries, uint8 *colourTable, uint8 fadeNow) {
	if (noEntries == 0) {
		RestorePalette();
		return RD_OK;
	}

	memcpy(&palCopy[startEntry][0], colourTable, noEntries * 4);
	if (fadeNow == RDPAL_INSTANT)
		g_system->set_palette((byte *) palCopy, startEntry, noEntries);

	return RD_OK;
}

int32 DimPalette(void) {
	byte *p = (byte *) palCopy;
	uint32 i;

	for (i = 0; i < 256 * 4; i++)
		p[i] /= 2;
	g_system->set_palette(p, 0, 256);
	return RD_OK;
}

int32 FadeUp(float time) {
	if (fadeStatus != RDFADE_BLACK && fadeStatus != RDFADE_NONE)
		return RDERR_FADEINCOMPLETE;

	fadeTotalTime = (int32) (time * 1000);
	fadeStatus = RDFADE_UP;
	fadeStartTime = SVM_timeGetTime();

	return RD_OK;
}

int32 FadeDown(float time) {
	if (fadeStatus != RDFADE_BLACK && fadeStatus != RDFADE_NONE)
		return RDERR_FADEINCOMPLETE;

	fadeTotalTime = (int32) (time * 1000);
	fadeStatus = RDFADE_DOWN;
	fadeStartTime = SVM_timeGetTime();

	return RD_OK;
}

uint8 GetFadeStatus(void) {
	return fadeStatus;
}

void FadeServer() {
	static int32 previousTime = 0;
	const byte *newPalette = (const byte *) fadePalette;
	int32 currentTime;
	int16 fadeMultiplier;
	int16 i;

	// This used to be called through a timer, but is now called from
	// ServiceWindows() instead, since that's the only place where we
	// actually update the screen.

	// If we're not in the process of fading, do nothing.
	if (fadeStatus != RDFADE_UP && fadeStatus != RDFADE_DOWN)
		return;

	// I don't know if this is necessary, but let's limit how often the
	// palette is updated, just to be safe.
	currentTime = SVM_timeGetTime();
	if (currentTime - previousTime <= 25)
		return;

	previousTime = currentTime;

	if (fadeStatus == RDFADE_UP) {
		if (currentTime >= fadeStartTime + fadeTotalTime) {
			fadeStatus = RDFADE_NONE;
			newPalette = (const byte *) palCopy;
		} else {
			fadeMultiplier = (int16) (((int32) (currentTime - fadeStartTime) * 256) / fadeTotalTime);
			for (i = 0; i < 256; i++) {
				fadePalette[i][0] = (palCopy[i][0] * fadeMultiplier) >> 8;
				fadePalette[i][1] = (palCopy[i][1] * fadeMultiplier) >> 8;
				fadePalette[i][2] = (palCopy[i][2] * fadeMultiplier) >> 8;
			}
		}
	} else {
		if (currentTime >= fadeStartTime + fadeTotalTime) {
			fadeStatus = RDFADE_BLACK;
			memset(fadePalette, 0, sizeof(fadePalette));
		} else {
			fadeMultiplier = (int16) (((int32) (fadeTotalTime - (currentTime - fadeStartTime)) * 256) / fadeTotalTime);
			for (i = 0; i < 256; i++) {
				fadePalette[i][0] = (palCopy[i][0] * fadeMultiplier) >> 8;
				fadePalette[i][1] = (palCopy[i][1] * fadeMultiplier) >> 8;
				fadePalette[i][2] = (palCopy[i][2] * fadeMultiplier) >> 8;
			}
		}
	}

	g_system->set_palette(newPalette, 0, 256);
}
