/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * 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.
 *
 * $URL: https://scummvm.svn.sourceforge.net/svnroot/scummvm/scummvm/tags/release-1-1-1/engines/cruise/gfxModule.cpp $
 * $Id: gfxModule.cpp 47541 2010-01-25 01:39:44Z lordhoto $
 *
 */


#include "common/system.h"
#include "common/endian.h"
#include "common/list.h"
#include "common/rect.h"

#include "cruise/cruise.h"
#include "cruise/cruise_main.h"

namespace Cruise {

uint8 page00[320 * 200];
uint8 page10[320 * 200];

char screen[320 * 200];
palEntry lpalette[256];

int palDirtyMin = 256;
int palDirtyMax = -1;

typedef Common::List<Common::Rect> RectList;
RectList _dirtyRects;
RectList _priorFrameRects;

bool _dirtyRectScreen = false;

gfxModuleDataStruct gfxModuleData = {
	0,			// use Tandy
	0,			// use EGA
	1,			// use VGA

	page00,			// pPage00
	page10,			// pPage10
};

void gfxModuleData_gfxClearFrameBuffer(uint8 *ptr) {
	memset(ptr, 0, 64000);
}

void gfxModuleData_gfxCopyScreen(const uint8 *sourcePtr, uint8 *destPtr) {
	memcpy(destPtr, sourcePtr, 320 * 200);
}

void outputBit(char *buffer, int bitPlaneNumber, uint8 data) {
	*(buffer + (8000 * bitPlaneNumber)) = data;
}

void convertGfxFromMode4(const uint8 *sourcePtr, int width, int height, uint8 *destPtr) {
	for (int y = 0; y < height; ++y) {
		for (int x = 0; x < width / 16; ++x) {
			for (int bit = 0; bit < 16; ++bit) {
				uint8 color = 0;
				for (int p = 0; p < 4; ++p) {
					if (READ_BE_UINT16(sourcePtr + p * 2) & (1 << (15 - bit))) {
						color |= 1 << p;
					}
				}
				*destPtr++ = color;
			}
			sourcePtr += 8;
		}
	}
}

void convertGfxFromMode5(const uint8 *sourcePtr, int width, int height, uint8 *destPtr) {
	int range = (width / 8) * height;

	for (int line = 0; line < 200; line++) {
		uint8 p0;
		uint8 p1;
		uint8 p2;
		uint8 p3;
		uint8 p4;

		for (int col = 0; col < 40; col++) {
			for (int bit = 0; bit < 8; bit++) {
				p0 = (sourcePtr[line*40 + col + range * 0] >> bit) & 1;
				p1 = (sourcePtr[line*40 + col + range * 1] >> bit) & 1;
				p2 = (sourcePtr[line*40 + col + range * 2] >> bit) & 1;
				p3 = (sourcePtr[line*40 + col + range * 3] >> bit) & 1;
				p4 = (sourcePtr[line*40 + col + range * 4] >> bit) & 1;

				destPtr[line * width + col * 8 + (7-bit)] = p0 | (p1 << 1) | (p2 << 2) | (p3 << 3) | (p4 << 4);
			}
		}
	}
}

void gfxModuleData_setDirtyColors(int min, int max) {
	if (min < palDirtyMin)
		palDirtyMin = min;
	if (max > palDirtyMax)
		palDirtyMax = max;
}

void gfxModuleData_setPalColor(int idx, int r, int g, int b) {
	lpalette[idx].R = r;
	lpalette[idx].G = g;
	lpalette[idx].B = b;
	gfxModuleData_setDirtyColors(idx, idx);
}

void gfxModuleData_setPalEntries(const byte *ptr, int start, int num) {
	int R, G, B, i;

	for (i = start; i < start + num; i++) {
		R = *(ptr++);
		G = *(ptr++);
		B = *(ptr++);

		lpalette[i].R = R;
		lpalette[i].G = G;
		lpalette[i].B = B;
		lpalette[i].A = 255;
	}

	gfxModuleData_setDirtyColors(start, start + num - 1);
}

void gfxModuleData_setPal256(const byte *ptr) {
	gfxModuleData_setPalEntries(ptr, 0, 256);
}

/*void gfxModuleData_setPal(uint8 *ptr) {
	int i;
	int R;
	int G;
	int B;

	for (i = 0; i < 256; i++) {
#define convertRatio 36.571428571428571428571428571429
		uint16 atariColor = *ptr;
		//bigEndianShortToNative(&atariColor);
		ptr ++;

		R = (int)(convertRatio * ((atariColor & 0x700) >> 8));
		G = (int)(convertRatio * ((atariColor & 0x070) >> 4));
		B = (int)(convertRatio * ((atariColor & 0x007)));

		if (R > 0xFF)
			R = 0xFF;
		if (G > 0xFF)
			G = 0xFF;
		if (B > 0xFF)
			B = 0xFF;

		lpalette[i].R = R;
		lpalette[i].G = G;
		lpalette[i].B = B;
		lpalette[i].A = 255;
	}

	gfxModuleData_setDirtyColors(0, 16);
}*/

void gfxModuleData_convertOldPalColor(uint16 oldColor, uint8 *pOutput) {
	int R;
	int G;
	int B;

#define convertRatio 36.571428571428571428571428571429

	R = (int)(convertRatio * ((oldColor & 0x700) >> 8));
	G = (int)(convertRatio * ((oldColor & 0x070) >> 4));
	B = (int)(convertRatio * ((oldColor & 0x007)));

	if (R > 0xFF)
		R = 0xFF;
	if (G > 0xFF)
		G = 0xFF;
	if (B > 0xFF)
		B = 0xFF;

	*(pOutput++) = R;
	*(pOutput++) = G;
	*(pOutput++) = B;
}

void gfxModuleData_gfxWaitVSync() {
}

void gfxModuleData_flip() {
}

void gfxCopyRect(const uint8 *sourceBuffer, int width, int height, byte *dest, int x, int y, int colour) {
	int xp, yp;

	for (yp = 0; yp < height; ++yp) {
		const uint8 *srcP = &sourceBuffer[yp * width];
		uint8 *destP = &dest[(y + yp) * 320 + x];

		for (xp = 0; xp < width; ++xp, ++srcP, ++destP) {
			uint8 v = *srcP;
			int xDest = x + xp;
			int yDest = y + yp;

			if ((v != 0) && (xDest >= 0) && (yDest >= 0) && (xDest < 320) && (yDest < 200))
				*destP = (v == 1) ? 0 : colour;
		}
	}
}

void gfxModuleData_Init() {
	memset(globalScreen, 0, 320 * 200);
	memset(page00, 0, 320 * 200);
	memset(page10, 0, 320 * 200);
}

void gfxModuleData_flipScreen() {
	memcpy(globalScreen, gfxModuleData.pPage00, 320 * 200);

	flip();
}

void gfxModuleData_addDirtyRect(const Common::Rect &r) {
	_dirtyRects.push_back(Common::Rect(	MAX(r.left, (int16)0), MAX(r.top, (int16)0),
		MIN(r.right, (int16)320), MIN(r.bottom, (int16)200)));
}

/**
 * Creates the union of two rectangles.
 */
static bool unionRectangle(Common::Rect &pDest, const Common::Rect &pSrc1, const Common::Rect &pSrc2) {
	pDest.left   = MIN(pSrc1.left, pSrc2.left);
	pDest.top    = MIN(pSrc1.top, pSrc2.top);
	pDest.right  = MAX(pSrc1.right, pSrc2.right);
	pDest.bottom = MAX(pSrc1.bottom, pSrc2.bottom);

	return !pDest.isEmpty();
}

static void mergeClipRects() {
	RectList::iterator rOuter, rInner;

	for (rOuter = _dirtyRects.begin(); rOuter != _dirtyRects.end(); ++rOuter) {
		rInner = rOuter;
		while (++rInner != _dirtyRects.end()) {

			if ((*rOuter).intersects(*rInner)) {
				// these two rectangles overlap, so translate it to a bigger rectangle
				// that contains both of them
				unionRectangle(*rOuter, *rOuter, *rInner);

				// remove the inner rect from the list
				_dirtyRects.erase(rInner);

				// move back to beginning of list
				rInner = rOuter;
			}
		}
	}
}

void gfxModuleData_updatePalette() {
	byte paletteRGBA[256 * 4];

	if (palDirtyMax != -1) {
		for (int i = palDirtyMin; i <= palDirtyMax; i++) {
			paletteRGBA[i * 4 + 0] = lpalette[i].R;
			paletteRGBA[i * 4 + 1] = lpalette[i].G;
			paletteRGBA[i * 4 + 2] = lpalette[i].B;
			paletteRGBA[i * 4 + 3] = 0xFF;
		}
		g_system->setPalette(paletteRGBA + palDirtyMin*4, palDirtyMin, palDirtyMax - palDirtyMin + 1);
		palDirtyMin = 256;
		palDirtyMax = -1;
	}
}

void gfxModuleData_updateScreen() {
	g_system->updateScreen();
	g_system->delayMillis(20);
}

void flip() {
	RectList::iterator dr;

	// Update the palette
	gfxModuleData_updatePalette();

	// Make a copy of the prior frame's dirty rects, and then backup the current frame's rects
	RectList tempList = _priorFrameRects;
	_priorFrameRects = _dirtyRects;

	// Merge the prior frame's dirty rects into the current frame's list
	for (dr = tempList.begin(); dr != tempList.end(); ++dr) {
		Common::Rect &r = *dr;
		_dirtyRects.push_back(Common::Rect(r.left, r.top, r.right, r.bottom));
	}

	// Merge any overlapping rects to simplify the drawing process
	mergeClipRects();

	// Copy any modified areas
	for (dr = _dirtyRects.begin(); dr != _dirtyRects.end(); ++dr) {
		Common::Rect &r = *dr;
		g_system->copyRectToScreen(globalScreen + 320 * r.top + r.left, 320,
			r.left, r.top, r.width(), r.height());
	}

	_dirtyRects.clear();

	// Allow the screen to update
	g_system->updateScreen();
}

void drawSolidBox(int32 x1, int32 y1, int32 x2, int32 y2, uint8 colour) {
	for (int y = y1; y < y2; ++y) {
		byte *p = &gfxModuleData.pPage00[y * 320 + x1];
		Common::set_to(p, p + (x2 - x1), colour);
	}
}

void resetBitmap(uint8 *dataPtr, int32 dataSize) {
	memset(dataPtr, 0, dataSize);
}

/**
 * This method compares a new background being switched in against the current background,
 * to figure out rectangles of changed areas for dirty rectangles
 */
void switchBackground(const byte *newBg) {
	const byte *bg = gfxModuleData.pPage00;
	int sliceXStart, sliceXEnd;

	// If both the upper corners are different, presume it's a full screen change
	if ((*newBg != *bg) && (*(newBg + 319) != *(bg + 319))) {
		gfxModuleData_addDirtyRect(Common::Rect(0, 0, 320, 200));
		return;
	}

	/* For an optimisation, any changes are stored as a series of slices than have a height of a single
	 * line each. It is left up to the screen redraw code to automatically merge these together
	 */

	for (int yp = 0; yp < 200; ++yp) {
		sliceXStart = -1; sliceXEnd = -1;
		for (int xp = 0; xp < 320; ++xp, ++bg, ++newBg) {
			if (*bg != *newBg) {
				if (sliceXStart == -1) {
					// Start of a new slice
					sliceXStart = xp;
					sliceXEnd = MIN(xp + 7, 320);
				} else
					// Carry on of changed area
					sliceXEnd = MAX(xp, sliceXEnd);

			} else if ((sliceXEnd != -1) && (xp >= (sliceXEnd + 10))) {
				// If more than 10 pixels have gone by without any changes, then end the slice
				gfxModuleData_addDirtyRect(Common::Rect(sliceXStart, yp, sliceXEnd + 1, MIN(yp + 2, 200)));
				sliceXStart = sliceXEnd = -1;
			}
		}

		if (sliceXStart != -1)
			gfxModuleData_addDirtyRect(Common::Rect(sliceXStart, yp, 320, MIN(yp + 2, 200)));
	}
}

} // End of namespace Cruise
