path: root/backends/sdl/sdl-common.cpp

/* ScummVM - Scumm Interpreter
 * Copyright (C) 2001/2002 The ScummVM project
 *
 * 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.
 *
 * $Header$
 *
 */

#include "sdl-common.h"
#include "sound/mididrv.h"
#include "common/scaler.h"
#include "common/engine.h"	// Only #included for error() and warning()

#include "scummvm.xpm"


bool atexit_proc_installed = false;
void atexit_proc() {
	SDL_ShowCursor(SDL_ENABLE);
	SDL_Quit();
}

OSystem *OSystem_SDL_create(int gfx_mode, bool full_screen) {
	return OSystem_SDL_Common::create(gfx_mode, full_screen);
}

OSystem *OSystem_SDL_Common::create(int gfx_mode, bool full_screen) {
	OSystem_SDL_Common *syst = OSystem_SDL_Common::create();
	syst->_mode = gfx_mode;
	syst->_full_screen = full_screen;

	if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER) ==-1) {
		error("Could not initialize SDL: %s.\n", SDL_GetError());
	}

	SDL_ShowCursor(SDL_DISABLE);
	
	// Enable unicode support if possible
	SDL_EnableUNICODE(1); 

#ifndef MACOSX		// Don't set icon on OS X, as we use a nicer external icon there
	// Setup the icon
	syst->setup_icon();
#endif

#ifndef MACOSX		// Work around a bug in OS X
	// Clean up on exit
	atexit_proc_installed = true;
 	atexit(atexit_proc);
#endif

	return syst;
}

void OSystem_SDL_Common::set_timer(int timer, int (*callback)(int)) {
	SDL_SetTimer(timer, (SDL_TimerCallback) callback);
}

OSystem_SDL_Common::OSystem_SDL_Common()
	: _screen(0), _screenWidth(0), _screenHeight(0),
	_tmpscreen(0), _tmpScreenWidth(0), _overlayVisible(false),
	_cdrom(0), _dirty_checksums(0),
	_mouseVisible(false), _mouseDrawn(false), _mouseData(0),
	_mouseHotspotX(0), _mouseHotspotY(0),
	_currentShakePos(0), _newShakePos(0)
{
	// allocate palette storage
	_currentPalette = (SDL_Color*)calloc(sizeof(SDL_Color), 256);

	// allocate the dirty rect storage
	_mouseBackup = (byte*)malloc(MAX_MOUSE_W * MAX_MOUSE_H * MAX_SCALING * 2);
	
	// reset mouse state
	memset(&km, 0, sizeof(km));
}

OSystem_SDL_Common::~OSystem_SDL_Common()
{
	if (_dirty_checksums)
		free(_dirty_checksums);
	free(_currentPalette);
	free(_mouseBackup);
}

void OSystem_SDL_Common::init_size(uint w, uint h) {

	// Avoid redundant res changes
	if ((int)w == _screenWidth && (int)h == _screenHeight)
		return;

	_screenWidth = w;
	_screenHeight = h;
	CKSUM_NUM = (_screenWidth*_screenHeight/(8*8));
	if (_dirty_checksums)
		free(_dirty_checksums);
	_dirty_checksums = (uint32*)calloc(CKSUM_NUM*2, sizeof(uint32));

	unload_gfx_mode();
	load_gfx_mode();

#ifdef MACOSX		// Work around a bug in OS X 10.1 related to OpenGL in windowed mode
	if (!atexit_proc_installed) {
		atexit_proc_installed = true;
		atexit(atexit_proc);
	}
#endif
}

void OSystem_SDL_Common::copy_rect(const byte *buf, int pitch, int x, int y, int w, int h) {
	if (_screen == NULL)
		return;

	if (pitch == _screenWidth && x==0 && y==0 && w==_screenWidth && h==_screenHeight && _mode_flags&DF_WANT_RECT_OPTIM) {
		/* Special, optimized case for full screen updates.
		 * It tries to determine what areas were actually changed,
		 * and just updates those, on the actual display. */
		add_dirty_rgn_auto(buf);
	} else {
		/* Clip the coordinates */
		if (x < 0) { w+=x; buf-=x; x = 0; }
		if (y < 0) { h+=y; buf-=y*pitch; y = 0; }
		if (w > _screenWidth-x) { w = _screenWidth - x; }
		if (h > _screenHeight-y) { h = _screenHeight - y; }
			
		if (w <= 0 || h <= 0)
			return;

		cksum_valid = false;
		add_dirty_rect(x, y, w, h);
	}

	/* FIXME: undraw mouse only if the draw rect intersects with the mouse rect */
	if (_mouseDrawn)
		undraw_mouse();

	if (SDL_LockSurface(_screen) == -1)
		error("SDL_LockSurface failed: %s.\n", SDL_GetError());

	byte *dst = (byte *)_screen->pixels + y * _screenWidth + x;
	do {
		memcpy(dst, buf, w);
		dst += _screenWidth;
		buf += pitch;
	} while (--h);

	SDL_UnlockSurface(_screen);
}


void OSystem_SDL_Common::move_screen(int dx, int dy, int height) {

	if ((dx == 0) && (dy == 0))
		return;

	if (dx == 0) {
		// vertical movement
		if (dy > 0) {
			// move down
			// copy from bottom to top
			for (int y = height - 1; y >= dy; y--)
				copy_rect((byte *)_screen->pixels + _screenWidth * (y - dy), _screenWidth, 0, y, _screenWidth, 1);
		} else {
			// move up
			// copy from top to bottom
			for (int y = 0; y < height + dx; y++)
				copy_rect((byte *)_screen->pixels + _screenWidth * (y - dy), _screenWidth, 0, y, _screenWidth, 1);
		}
	} else if (dy == 0) {
		// horizontal movement
		if (dx > 0) {
			// move right
			// copy from right to left
			for (int x = _screenWidth - 1; x >= dx; x--)
				copy_rect((byte *)_screen->pixels + x - dx, _screenWidth, x, 0, 1, height);
		} else {
			// move left
			// copy from left to right
			for (int x = 0; x < _screenWidth; x++)
				copy_rect((byte *)_screen->pixels + x - dx, _screenWidth, x, 0, 1, height);
		}
	} else {
		// free movement
		// not neccessary for now
	}
}

void OSystem_SDL_Common::add_dirty_rect(int x, int y, int w, int h) {
	if (_forceFull)
		return;

	if (_num_dirty_rects == NUM_DIRTY_RECT)
		_forceFull = true;
	else {
		SDL_Rect *r = &_dirty_rect_list[_num_dirty_rects++];
		
		// Extend the dirty region by 1 pixel for scalers
		// that "smear" the screen, e.g. 2xSAI
		if (_mode_flags & DF_UPDATE_EXPAND_1_PIXEL) {
			x--;
			y--;
			w+=2;
			h+=2;
		}

		// clip
		if (x < 0) { w+=x; x=0; }
		if (y < 0) { h+=y; y=0; }
		if (w > _screenWidth-x) { w = _screenWidth - x; }
		if (h > _screenHeight-y) { h = _screenHeight - y; }
	
		r->x = x;
		r->y = y;
		r->w = w;
		r->h = h;
	}
}

#define ROL(a,n) a = (a<<(n)) | (a>>(32-(n)))
#define DOLINE(x) a ^= ((uint32*)buf)[0+(x)*(_screenWidth/4)]; b ^= ((uint32*)buf)[1+(x)*(_screenWidth/4)]
void OSystem_SDL_Common::mk_checksums(const byte *buf) {
	uint32 *sums = _dirty_checksums;
	uint x,y;
	const uint last_x = (uint)_screenWidth/8;
	const uint last_y = (uint)_screenHeight/8;

	/* the 8x8 blocks in buf are enumerated starting in the top left corner and
	 * reading each line at a time from left to right */
	for(y=0; y != last_y; y++, buf+=_screenWidth*(8-1))
		for(x=0; x != last_x; x++, buf+=8) {
			uint32 a = x;
			uint32 b = y;

			DOLINE(0); ROL(a,13); ROL(b,11);
			DOLINE(2); ROL(a,13); ROL(b,11);
			DOLINE(4); ROL(a,13); ROL(b,11);
			DOLINE(6); ROL(a,13); ROL(b,11);

			a*=0xDEADBEEF;
			b*=0xBAADF00D;

			DOLINE(1); ROL(a,13); ROL(b,11);
			DOLINE(3); ROL(a,13); ROL(b,11);
			DOLINE(5); ROL(a,13); ROL(b,11);
			DOLINE(7); ROL(a,13); ROL(b,11);

			/* output the checksum for this block */
			*sums++=a+b;
		}
}
#undef DOLINE
#undef ROL


void OSystem_SDL_Common::add_dirty_rgn_auto(const byte *buf) {
	assert( ((uint32)buf & 3) == 0);
	
	/* generate a table of the checksums */
	mk_checksums(buf);

	if (!cksum_valid) {
		_forceFull = true;
		cksum_valid = true;
	}

	/* go through the checksum list, compare it with the previous checksums,
		 and add all dirty rectangles to a list. try to combine small rectangles
		 into bigger ones in a simple way */
	if (!_forceFull) {
		int x,y,w;
		uint32 *ck = _dirty_checksums;
		
		for(y=0; y!=_screenHeight/8; y++) {
			for(x=0; x!=_screenWidth/8; x++,ck++) {
				if (ck[0] != ck[CKSUM_NUM]) {
					/* found a dirty 8x8 block, now go as far to the right as possible,
						 and at the same time, unmark the dirty status by setting old to new. */
					w=0;
					do {
						ck[w+CKSUM_NUM] = ck[w];
						w++;
					} while (x+w != _screenWidth/8 && ck[w] != ck[w+CKSUM_NUM]);
					
					add_dirty_rect(x*8, y*8, w*8, 8);

					if (_forceFull)
						goto get_out;
				}
			}
		}
	} else {
		get_out:;
		/* Copy old checksums to new */
		memcpy(_dirty_checksums + CKSUM_NUM, _dirty_checksums, CKSUM_NUM * sizeof(uint32));
	}
}

void OSystem_SDL_Common::kbd_mouse() {
	uint32 time = get_msecs();
	if (time >= km.last_time + km.delay_time) {
		km.last_time = time;
		if (km.x_down_count == 1) {
			km.x_down_time = time;
			km.x_down_count = 2;
		}
		if (km.y_down_count == 1) {
			km.y_down_time = time;      
			km.y_down_count = 2;
		}

		if (km.x_vel || km.y_vel) {
			if (km.x_down_count) {
				if (time > km.x_down_time + km.delay_time*12) {
					if (km.x_vel > 0)
						km.x_vel++;
					else
						km.x_vel--;
				} else if (time > km.x_down_time + km.delay_time*8) {
					if (km.x_vel > 0)
						km.x_vel = 5;
					else
						km.x_vel = -5;
				}
			}
			if (km.y_down_count) {
				if (time > km.y_down_time + km.delay_time*12) {
					if (km.y_vel > 0)
						km.y_vel++;
					else
						km.y_vel--;
				} else if (time > km.y_down_time + km.delay_time*8) {
					if (km.y_vel > 0)
						km.y_vel = 5;
					else
						km.y_vel = -5;
				}
			}

			km.x += km.x_vel;
			km.y += km.y_vel;

			if (km.x < 0) {
				km.x = 0;
				km.x_vel = -1;
				km.x_down_count = 1;
			} else if (km.x > km.x_max) {
				km.x = km.x_max;
				km.x_vel = 1;
				km.x_down_count = 1;
			}

			if (km.y < 0) {
				km.y = 0;
				km.y_vel = -1;
				km.y_down_count = 1;
			} else if (km.y > km.y_max) {
				km.y = km.y_max;
				km.y_vel = 1;
				km.y_down_count = 1;
			}

			SDL_WarpMouse(km.x, km.y);
		}
	}
}

bool OSystem_SDL_Common::show_mouse(bool visible) {
	if (_mouseVisible == visible)
		return visible;
	
	bool last = _mouseVisible;
	_mouseVisible = visible;

	if (visible)
		draw_mouse();
	else
		undraw_mouse();

	return last;
}
	
void OSystem_SDL_Common::set_mouse_pos(int x, int y) {
	if (x != _mouseCurState.x || y != _mouseCurState.y) {
		_mouseCurState.x = x;
		_mouseCurState.y = y;
		undraw_mouse();
	}
}
	
void OSystem_SDL_Common::set_mouse_cursor(const byte *buf, uint w, uint h, int hotspot_x, int hotspot_y) {
	_mouseCurState.w = w;
	_mouseCurState.h = h;

	_mouseHotspotX = hotspot_x;
	_mouseHotspotY = hotspot_y;

	_mouseData = (byte*)buf;

	undraw_mouse();
}
	
void OSystem_SDL_Common::set_shake_pos(int shake_pos) {
	_newShakePos = shake_pos;
}
		
uint32 OSystem_SDL_Common::get_msecs() {
	return SDL_GetTicks();	
}
	
void OSystem_SDL_Common::delay_msecs(uint msecs) {
	SDL_Delay(msecs);
}
	
void *OSystem_SDL_Common::create_thread(ThreadProc *proc, void *param) {
	return SDL_CreateThread(proc, param);
}

static int mapKey(SDLKey key, SDLMod mod, Uint16 unicode)
{
	if (key >= SDLK_F1 && key <= SDLK_F9) {
		return key - SDLK_F1 + 315;
	} else if (key >= SDLK_UP && key <= SDLK_PAGEDOWN) {
		return key;
	} else if (unicode) {
		return unicode;
	} else if (key >= 'a' && key <= 'z' && mod & KMOD_SHIFT) {
		return key & ~0x20;
	} else if (key >= SDLK_NUMLOCK && key <= SDLK_EURO) {
		return 0;
	}
	return key;
}
	
bool OSystem_SDL_Common::poll_event(Event *event) {
	SDL_Event ev;
	kbd_mouse();

	for(;;) {
		if (!SDL_PollEvent(&ev))
			return false;

		switch(ev.type) {
		case SDL_KEYDOWN: {
				byte b = 0;
				if (ev.key.keysym.mod & KMOD_SHIFT)
					b |= KBD_SHIFT;
				if (ev.key.keysym.mod & KMOD_CTRL)
					b |= KBD_CTRL;
				if (ev.key.keysym.mod & KMOD_ALT)
					b |= KBD_ALT;
				event->kbd.flags = b;

				// Alt-Return toggles full screen mode				
				if (b == KBD_ALT && ev.key.keysym.sym==SDLK_RETURN) {
					property(PROP_TOGGLE_FULLSCREEN, NULL);
					break;
				}

				if ((b == KBD_CTRL && ev.key.keysym.sym=='z') || (b == KBD_ALT && ev.key.keysym.sym=='x')) {
					quit();
					break;
				}
				// Ctr-Alt-1 till Ctrl-Alt-7 will change the GFX mode
				if (b == (KBD_CTRL|KBD_ALT) && 
				    (ev.key.keysym.sym>='1') && (ev.key.keysym.sym<='7')) {
					Property prop;
					prop.gfx_mode = ev.key.keysym.sym - '1';
					property(PROP_SET_GFX_MODE, &prop);
					break;
				}
#ifdef MACOSX
				// quit on Cmd-Q on Mac
				if ((ev.key.keysym.mod & KMOD_META) && ev.key.keysym.sym=='q') {
					quit();
					break;
				}
#endif

#ifdef QTOPIA
				// quit on fn+backspace on zaurus
				if (ev.key.keysym.sym == 127) {
					quit();
					break;
				}
				// map menu key (f11) to f5 (scumm menu)
				if (ev.key.keysym.sym == SDLK_F11) {
					event->event_code = EVENT_KEYDOWN;
					event->kbd.keycode = SDLK_F5;
					event->kbd.ascii = mapKey(SDLK_F5, ev.key.keysym.mod, 0);
				}
				// map center (space) to tab (default action )
				// I wanted to map the calendar button but the calendar comes up
				//
				else if (ev.key.keysym.sym == SDLK_SPACE) {
					event->event_code = EVENT_KEYDOWN;
					event->kbd.keycode = SDLK_TAB;
					event->kbd.ascii = mapKey(SDLK_TAB, ev.key.keysym.mod, 0);
				}
				// since we stole space (pause) above we'll rebind it to the tab key on the keyboard
				else if (ev.key.keysym.sym == SDLK_TAB) {
					event->event_code = EVENT_KEYDOWN;
					event->kbd.keycode = SDLK_SPACE;
					event->kbd.ascii = mapKey(SDLK_SPACE, ev.key.keysym.mod, 0);
				}
				else {
				// let the events fall through if we didn't change them, this may not be the best way to
				// set it up, but i'm not sure how sdl would like it if we let if fall through then redid it though.
				// and yes i have an huge terminal size so i dont wrap soon enough.
					event->event_code = EVENT_KEYDOWN;
					event->kbd.keycode = ev.key.keysym.sym;
					event->kbd.ascii = mapKey(ev.key.keysym.sym, ev.key.keysym.mod, ev.key.keysym.unicode);
				}
#else
				event->event_code = EVENT_KEYDOWN;
				event->kbd.keycode = ev.key.keysym.sym;
				event->kbd.ascii = mapKey(ev.key.keysym.sym, ev.key.keysym.mod, ev.key.keysym.unicode);
#endif
				
				switch(ev.key.keysym.sym) {
					case SDLK_LEFT:
						km.x_vel = -1;
						km.x_down_count = 1;
					break;
					case SDLK_RIGHT:
						km.x_vel =  1;
						km.x_down_count = 1;
					break;
					case SDLK_UP:
						km.y_vel = -1;
						km.y_down_count = 1;
					break;
					case SDLK_DOWN:
						km.y_vel =  1;
						km.y_down_count = 1;
					break;
					default:
					break;
				}
	
				return true;
			}

		case SDL_KEYUP: {
			event->event_code = EVENT_KEYUP;
			event->kbd.keycode = ev.key.keysym.sym;
			event->kbd.ascii = mapKey(ev.key.keysym.sym, ev.key.keysym.mod, ev.key.keysym.unicode);

				switch(ev.key.keysym.sym){
					case SDLK_LEFT:                
						if (km.x_vel < 0) {
							km.x_vel = 0;
							km.x_down_count = 0;
						}
					break;
					case SDLK_RIGHT:
						if (km.x_vel > 0) {
							km.x_vel = 0;
							km.x_down_count = 0;
						}
					break;
					case SDLK_UP:
						if (km.y_vel < 0) {
							km.y_vel = 0;
							km.y_down_count = 0;
						}
					break;
					case SDLK_DOWN:
						if (km.y_vel > 0) {
							km.y_vel = 0;
							km.y_down_count = 0;
						}
					break;
					default:
					break;
				}
				return true;
			}

		case SDL_MOUSEMOTION:
			event->event_code = EVENT_MOUSEMOVE;
			km.x = event->mouse.x = ev.motion.x;
			km.y = event->mouse.y = ev.motion.y;

			event->mouse.x /= _scaleFactor;
			event->mouse.y /= _scaleFactor;

			return true;

		case SDL_MOUSEBUTTONDOWN:
			if (ev.button.button == SDL_BUTTON_LEFT)
				event->event_code = EVENT_LBUTTONDOWN;
			else if (ev.button.button == SDL_BUTTON_RIGHT)
				event->event_code = EVENT_RBUTTONDOWN;
#if defined(SDL_BUTTON_WHEELUP) && defined(SDL_BUTTON_WHEELDOWN)
			else if (ev.button.button == SDL_BUTTON_WHEELUP)
				event->event_code = EVENT_WHEELUP;
			else if (ev.button.button == SDL_BUTTON_WHEELDOWN)
				event->event_code = EVENT_WHEELDOWN;
#endif
			else
				break;
			km.x = event->mouse.x = ev.motion.x;
			km.y = event->mouse.y = ev.motion.y;
			event->mouse.x /= _scaleFactor;
			event->mouse.y /= _scaleFactor;

			return true;

		case SDL_MOUSEBUTTONUP:
			if (ev.button.button == SDL_BUTTON_LEFT)
				event->event_code = EVENT_LBUTTONUP;
			else if (ev.button.button == SDL_BUTTON_RIGHT)
				event->event_code = EVENT_RBUTTONUP;
			else
				break;
			event->mouse.x = ev.button.x;
			event->mouse.y = ev.button.y;
			event->mouse.x /= _scaleFactor;
			event->mouse.y /= _scaleFactor;
			return true;

		case SDL_QUIT:
			quit();
		}
	}
}
	
bool OSystem_SDL_Common::set_sound_proc(void *param, SoundProc *proc, byte format) {
	SDL_AudioSpec desired;

	/* only one format supported at the moment */

	desired.freq = SAMPLES_PER_SEC;
	desired.format = AUDIO_S16SYS;
	desired.channels = 2;
	desired.samples = 2048;
	desired.callback = proc;
	desired.userdata = param;
	if (SDL_OpenAudio(&desired, NULL) != 0) {
		return false;
	}
	SDL_PauseAudio(0);
	return true;
}

uint32 OSystem_SDL_Common::property(int param, Property *value) {
	switch(param) {

	case PROP_GET_FULLSCREEN:
		return _full_screen;

	case PROP_SET_WINDOW_CAPTION:
		SDL_WM_SetCaption(value->caption, value->caption);
		return 1;

	case PROP_OPEN_CD:
		if (SDL_InitSubSystem(SDL_INIT_CDROM) == -1)
			_cdrom = NULL;
		else {
			_cdrom = SDL_CDOpen(value->cd_num);
			/* Did if open? Check if _cdrom is NULL */
			if (!_cdrom) {
				warning("Couldn't open drive: %s\n", SDL_GetError());
			}
		}
		break;

	case PROP_SHOW_DEFAULT_CURSOR:
		SDL_ShowCursor(value->show_cursor ? SDL_ENABLE : SDL_DISABLE);		
		break;

	case PROP_GET_SAMPLE_RATE:
		return SAMPLES_PER_SEC;
	}

	return 0;
}
		
void OSystem_SDL_Common::quit() {
	if(_cdrom) {
		SDL_CDStop(_cdrom);
		SDL_CDClose(_cdrom);
	}
	unload_gfx_mode();		
	exit(0);
}

void OSystem_SDL_Common::draw_mouse() {
	if (_mouseDrawn || !_mouseVisible)
		return;

	int x = _mouseCurState.x - _mouseHotspotX;
	int y = _mouseCurState.y - _mouseHotspotY;
	int w = _mouseCurState.w;
	int h = _mouseCurState.h;
	byte color;
	byte *src = _mouseData;		// Image representing the mouse

	// clip the mouse rect, and addjust the src pointer accordingly
	if (x < 0) {
		w += x;
		src -= x;
		x = 0;
	}
	if (y < 0) {
		h += y;
		src -= y * _mouseCurState.w;
		y = 0;
	}

	if (w > _screenWidth - x)
		w = _screenWidth - x;
	if (h > _screenHeight - y)
		h = _screenHeight - y;

	// Quick check to see if anything has to be drawn at all
	if (w <= 0 || h <= 0)
		return;

	// Store the bounding box so that undraw mouse can restore the area the
	// mouse currently covers to its original content.
	_mouseOldState.x = x;
	_mouseOldState.y = y;
	_mouseOldState.w = w;
	_mouseOldState.h = h;

	// Draw the mouse cursor; backup the covered area in "bak"
	
	if (SDL_LockSurface(_overlayVisible ? _tmpscreen : _screen) == -1)
		error("SDL_LockSurface failed: %s.\n", SDL_GetError());
	
	// Mark as dirty
	add_dirty_rect(x, y, w, h);

	if (!_overlayVisible) {
		byte *bak = _mouseBackup;		// Surface used to backup the area obscured by the mouse
		byte *dst;					// Surface we are drawing into
	
		dst = (byte *)_screen->pixels + y * _screenWidth + x;
		while (h > 0) {
			int width = w;
			while (width > 0) {
				*bak++ = *dst;
				color = *src++;
				if (color != 0xFF)	// 0xFF = transparent, don't draw
					*dst = color;
				dst++;
				width--;
			}
			src += _mouseCurState.w - w;
			bak += MAX_MOUSE_W - w;
			dst += _screenWidth - w;
			h--;
		}
	
	} else {
		uint16 *bak = (uint16*)_mouseBackup;	// Surface used to backup the area obscured by the mouse
		uint16 *dst;					// Surface we are drawing into
	
		dst = (uint16 *)_tmpscreen->pixels + (y+1) * _tmpScreenWidth + (x+1);
		while (h > 0) {
			int width = w;
			while (width > 0) {
				*bak++ = *dst;
				color = *src++;
				if (color != 0xFF)	// 0xFF = transparent, don't draw
					*dst = RBGToColor(_currentPalette[color].r, _currentPalette[color].g, _currentPalette[color].b);
				dst++;
				width--;
			}
			src += _mouseCurState.w - w;
			bak += MAX_MOUSE_W - w;
			dst += _tmpScreenWidth - w;
			h--;
		}
	
	}

	SDL_UnlockSurface(_overlayVisible ? _tmpscreen : _screen);
	
	// Finally, set the flag to indicate the mouse has been drawn
	_mouseDrawn = true;
}

void OSystem_SDL_Common::undraw_mouse() {
	if (!_mouseDrawn)
		return;
	_mouseDrawn = false;

	if (SDL_LockSurface(_overlayVisible ? _tmpscreen : _screen) == -1)
		error("SDL_LockSurface failed: %s.\n", SDL_GetError());

	const int old_mouse_x = _mouseOldState.x;
	const int old_mouse_y = _mouseOldState.y;
	const int old_mouse_w = _mouseOldState.w;
	const int old_mouse_h = _mouseOldState.h;
	int x, y;

	if (!_overlayVisible) {
	
		byte *dst, *bak = _mouseBackup;
	
		// No need to do clipping here, since draw_mouse() did that already
		dst = (byte *)_screen->pixels + old_mouse_y * _screenWidth + old_mouse_x;
		for (y = 0; y < old_mouse_h; ++y, bak += MAX_MOUSE_W, dst += _screenWidth) {
			for (x = 0; x < old_mouse_w; ++x) {
				dst[x] = bak[x];
			}
		}
	
	} else {

		uint16 *dst, *bak = (uint16 *)_mouseBackup;
	
		// No need to do clipping here, since draw_mouse() did that already
		dst = (uint16 *)_tmpscreen->pixels + (old_mouse_y+1) * _tmpScreenWidth + (old_mouse_x+1);
		for (y = 0; y < old_mouse_h; ++y, bak += MAX_MOUSE_W, dst += _tmpScreenWidth) {
			for (x = 0; x < old_mouse_w; ++x) {
				dst[x] = bak[x];
			}
		}
	}

	add_dirty_rect(old_mouse_x, old_mouse_y, old_mouse_w, old_mouse_h);

	SDL_UnlockSurface(_overlayVisible ? _tmpscreen : _screen);
}

void OSystem_SDL_Common::stop_cdrom() {	/* Stop CD Audio in 1/10th of a second */
	cd_stop_time = SDL_GetTicks() + 100;
	cd_num_loops = 0;

}

void OSystem_SDL_Common::play_cdrom(int track, int num_loops, int start_frame, int end_frame) {
	if (!num_loops && !start_frame)
		return;

	if (!_cdrom)
		return;
	
	if (end_frame > 0)
		end_frame+=5;

	cd_track = track;
	cd_num_loops = num_loops;
	cd_start_frame = start_frame;

	SDL_CDStatus(_cdrom);
	if (start_frame == 0 && end_frame == 0)
		SDL_CDPlayTracks(_cdrom, track, 0, 1, 0);
	else
		SDL_CDPlayTracks(_cdrom, track, start_frame, 0, end_frame);
	cd_end_frame = end_frame;
	cd_stop_time = 0;
	cd_end_time = SDL_GetTicks() + _cdrom->track[track].length * 1000 / CD_FPS;
}

bool OSystem_SDL_Common::poll_cdrom() {
	if (!_cdrom)
		return false;

	return (cd_num_loops != 0 && (SDL_GetTicks() < cd_end_time || SDL_CDStatus(_cdrom) != CD_STOPPED));
}

void OSystem_SDL_Common::update_cdrom() {
	if (!_cdrom)
		return;
		
	if (cd_stop_time != 0 && SDL_GetTicks() >= cd_stop_time) {
		SDL_CDStop(_cdrom);
		cd_num_loops = 0;
		cd_stop_time = 0;
		return;
	}

	if (cd_num_loops == 0 || SDL_GetTicks() < cd_end_time)
		return;

	if (cd_num_loops != 1 && SDL_CDStatus(_cdrom) != CD_STOPPED) {
		// Wait another second for it to be done
		cd_end_time += 1000;
		return;
	}

	if (cd_num_loops > 0)
		cd_num_loops--;

	if (cd_num_loops != 0) {
		if (cd_start_frame == 0 && cd_end_frame == 0)
			SDL_CDPlayTracks(_cdrom, cd_track, 0, 1, 0);
		else
			SDL_CDPlayTracks(_cdrom, cd_track, cd_start_frame, 0, cd_end_frame);
		cd_end_time = SDL_GetTicks() + _cdrom->track[cd_track].length * 1000 / CD_FPS;
	}
}

void OSystem_SDL_Common::setup_icon() {
	int w, h, ncols, nbytes, i;
	unsigned int rgba[256], icon[32 * 32];
	unsigned char mask[32][4];

	sscanf(scummvm_icon[0], "%d %d %d %d", &w, &h, &ncols, &nbytes);
	if ((w != 32) || (h != 32) || (ncols > 255) || (nbytes > 1)) {
		warning("Could not load the icon (%d %d %d %d)", w, h, ncols, nbytes);
		return;
	}
	for (i = 0; i < ncols; i++) {
		unsigned char code;
		char color[32];
		unsigned int col;
		sscanf(scummvm_icon[1 + i], "%c c %s", &code, color);
		if (!strcmp(color, "None"))
			col = 0x00000000;
		else if (!strcmp(color, "black"))
			col = 0xFF000000;
		else if (color[0] == '#') {
			sscanf(color + 1, "%06x", &col);
			col |= 0xFF000000;
		} else {
			warning("Could not load the icon (%d %s - %s) ", code, color, scummvm_icon[1 + i]);
			return;
		}
		
		rgba[code] = col;
	}
	memset(mask, 0, sizeof(mask));
	for (h = 0; h < 32; h++) {
		char *line = scummvm_icon[1 + ncols + h];
		for (w = 0; w < 32; w++) {
			icon[w + 32 * h] = rgba[line[w]];
			if (rgba[line[w]] & 0xFF000000) {
				mask[h][w >> 3] |= 1 << (7 - (w & 0x07));
			}
		}
	}

	SDL_Surface *sdl_surf = SDL_CreateRGBSurfaceFrom(icon, 32, 32, 32, 32 * 4, 0xFF0000, 0x00FF00, 0x0000FF, 0xFF000000);
	SDL_WM_SetIcon(sdl_surf, (unsigned char *) mask);
}

void *OSystem_SDL_Common::create_mutex(void) {
	return (void *) SDL_CreateMutex();
}

void OSystem_SDL_Common::lock_mutex(void *mutex) {
	SDL_mutexP((SDL_mutex *) mutex);
}

void OSystem_SDL_Common::unlock_mutex(void *mutex) {
	SDL_mutexV((SDL_mutex *) mutex);
}

void OSystem_SDL_Common::delete_mutex(void *mutex) {
	SDL_DestroyMutex((SDL_mutex *) mutex);
}

void OSystem_SDL_Common::show_overlay()
{
	// hide the mouse
	undraw_mouse();

	_overlayVisible = true;
	clear_overlay();
}

void OSystem_SDL_Common::hide_overlay()
{
	// hide the mouse
	undraw_mouse();

	_overlayVisible = false;
	_forceFull = true;
}

void OSystem_SDL_Common::clear_overlay()
{
	if (!_overlayVisible)
		return;
	
	// hide the mouse
	undraw_mouse();

	// Clear the overlay by making the game screen "look through" everywhere.
	SDL_Rect src, dst;
	src.x = src.y = 0;
	dst.x = dst.y = 1;
	src.w = dst.w = _screenWidth;
	src.h = dst.h = _screenHeight;
	if (SDL_BlitSurface(_screen, &src, _tmpscreen, &dst) != 0)
		error("SDL_BlitSurface failed: %s", SDL_GetError());

	_forceFull = true;
}

void OSystem_SDL_Common::grab_overlay(int16 *buf, int pitch)
{
	if (!_overlayVisible)
		return;

	if (_tmpscreen == NULL)
		return;

	// hide the mouse
	undraw_mouse();

	if (SDL_LockSurface(_tmpscreen) == -1)
		error("SDL_LockSurface failed: %s.\n", SDL_GetError());

	int16 *src = (int16 *)_tmpscreen->pixels + _tmpScreenWidth + 1;
	int h = _screenHeight;
	do {
		memcpy(buf, src, _screenWidth*2);
		src += _tmpScreenWidth;
		buf += pitch;
	} while (--h);

	SDL_UnlockSurface(_tmpscreen);
}

void OSystem_SDL_Common::copy_rect_overlay(const int16 *buf, int pitch, int x, int y, int w, int h)
{
	if (!_overlayVisible)
		return;

	if (_tmpscreen == NULL)
		return;

	// Clip the coordinates
	if (x < 0) { w+=x; buf-=x; x = 0; }
	if (y < 0) { h+=y; buf-=y*pitch; y = 0; }
	if (w > _screenWidth-x) { w = _screenWidth - x; }
	if (h > _screenHeight-y) { h = _screenHeight - y; }
	if (w <= 0 || h <= 0)
		return;
	
	// Mark the modified region as dirty
	cksum_valid = false;
	add_dirty_rect(x, y, w, h);

	/* FIXME: undraw mouse only if the draw rect intersects with the mouse rect */
	undraw_mouse();

	if (SDL_LockSurface(_tmpscreen) == -1)
		error("SDL_LockSurface failed: %s.\n", SDL_GetError());

	int16 *dst = (int16 *)_tmpscreen->pixels + (y+1) * _tmpScreenWidth + (x+1);
	do {
		memcpy(dst, buf, w*2);
		dst += _tmpScreenWidth;
		buf += pitch;
	} while (--h);

	SDL_UnlockSurface(_tmpscreen);
}

int16 OSystem_SDL_Common::RBGToColor(uint8 r, uint8 g, uint8 b)
{
	return SDL_MapRGB(_tmpscreen->format, r, g, b);
}

void OSystem_SDL_Common::colorToRBG(int16 color, uint8 &r, uint8 &g, uint8 &b)
{
	SDL_GetRGB(color, _tmpscreen->format, &r, &g, &b);
}