(svn r14630) -Add: support Allegro as video backend.

6 files changed, 628 insertions, 1 deletions

diff --git a/config.lib b/config.lib
index 14af7a3f0..a2352b226 100644
--- a/config.lib
+++ b/config.lib
@@ -56,6 +56,7 @@ set_default() {
 	with_osx_sysroot="1"
 	with_application_bundle="1"
 	with_menu_entry="1"
+	with_allegro="1"
 	with_sdl="1"
 	with_cocoa="1"
 	with_zlib="1"
@@ -121,6 +122,7 @@ set_default() {
 		enable_cocoa_quickdraw
 		with_osx_sysroot
 		with_application_bundle
+		with_allegro
 		with_sdl
 		with_cocoa
 		with_zlib
@@ -285,6 +287,10 @@ detect_params() {
 			--enable-cocoa-quickdraw)     enable_cocoa_quickdraw="2";;
 			--enable-cocoa-quickdraw=*)   enable_cocoa_quickdraw="$optarg";;
 
+			--with-allegro)               with_allegro="2";;
+			--without-allegro)            with_allegro="0";;
+			--with-allegro=*)             with_allegro="$optarg";;
+
 			--with-sdl)                   with_sdl="2";;
 			--without-sdl)                with_sdl="0";;
 			--with-sdl=*)                 with_sdl="$optarg";;
@@ -559,6 +565,7 @@ check_params() {
 		sleep 5
 	fi
 
+	detect_allegro
 	detect_sdl
 	detect_cocoa
 
@@ -577,7 +584,7 @@ check_params() {
 			log 1 "checking GDI video driver... not Windows, skipping"
 		fi
 
-		if [ -z "$sdl_config" ] && [ "$with_cocoa" = 0 ] && [ "$os" != "MINGW" ] && [ "$os" != "CYGWIN" ] && [ "$os" != "WINCE" ]; then
+		if [ -z "$allegro_config" ] && [ -z "$sdl_config" ] && [ "$with_cocoa" = 0 ] && [ "$os" != "MINGW" ] && [ "$os" != "CYGWIN" ] && [ "$os" != "WINCE" ]; then
 			log 1 "WARNING: no video driver found, building dedicated only"
 			enable_dedicated="1"
 			sleep 1
@@ -1164,6 +1171,18 @@ make_cflags_and_ldflags() {
 		CFLAGS="$CFLAGS -DWIN"
 	fi
 
+	if [ -n "$allegro_config" ]; then
+		CFLAGS="$CFLAGS -DWITH_ALLEGRO"
+		CFLAGS="$CFLAGS `$allegro_config --cflags`"
+		if [ "$os" != "MINGW" ] && [ "$os" != "CYGWIN" ] && [ "$os" != "WINCE" ]; then
+			if [ "$enable_static" != "0" ]; then
+				LIBS="$LIBS `$allegro_config --static --libs`"
+			else
+				LIBS="$LIBS `$allegro_config --libs`"
+			fi
+		fi
+	fi
+
 	if [ -n "$sdl_config" ]; then
 		CFLAGS="$CFLAGS -DWITH_SDL"
 		CFLAGS="$CFLAGS `$sdl_config --cflags`"
@@ -1740,6 +1759,72 @@ detect_os() {
 	fi
 }
 
+detect_allegro() {
+	# 0 means no, 1 is auto-detect, 2 is force
+	if [ "$with_allegro" = "0" ]; then
+		log 1 "checking Allegro... disabled"
+
+		allegro_config=""
+		return 0
+	fi
+
+	if [ "$with_allegro" = "2" ] && [ "$with_cocoa" = "2" ]; then
+		log 1 "configure: error: it is impossible to compile both Allegro and COCOA"
+		log 1 "configure: error: please deselect one of them and try again"
+		exit 1
+	fi
+
+	if [ "$with_allegro" = "2" ] && [ "$enable_dedicated" != "0" ]; then
+		log 1 "configure: error: it is impossible to compile a dedicated with Allegro"
+		log 1 "configure: error: please deselect one of them and try again"
+		exit 1
+	fi
+
+	if [ "$enable_dedicated" != "0" ]; then
+		log 1 "checking Allegro... dedicated server, skipping"
+
+		allegro_config=""
+		return 0
+	fi
+
+	# By default on OSX we don't use SDL. The rest is auto-detect
+	if [ "$with_allegro" = "1" ] && [ "$os" = "OSX" ] && [ "$with_cocoa" != "0" ]; then
+		log 1 "checking SDL... OSX, skipping"
+
+		allegro_config=""
+		return 0
+	fi
+
+	if [ "$with_allegro" = "1" ] || [ "$with_allegro" = "" ] || [ "$with_allegro" = "2" ]; then
+		allegro_config="allegro-config"
+	else
+		allegro_config="$with_allegro"
+	fi
+
+	version=`$allegro_config --version 2>/dev/null`
+	ret=$?
+	log 2 "executing $allegro_config --version"
+	log 2 "  returned $version"
+	log 2 "  exit code $ret"
+
+	if [ -z "$version" ] || [ "$ret" != "0" ]; then
+		log 1 "checking Allegro... not found"
+
+		# It was forced, so it should be found.
+		if [ "$with_allegro" != "1" ]; then
+			log 1 "configure: error: allegro-config couldn't be found"
+			log 1 "configure: error: you supplied '$with_allegro', but it seems invalid"
+			exit 1
+		fi
+
+		allegro_config=""
+		return 0
+	fi
+
+	log 1 "checking Allegro... found"
+}
+
+
 detect_sdl() {
 	# 0 means no, 1 is auto-detect, 2 is force
 	if [ "$with_sdl" = "0" ]; then
@@ -2701,6 +2786,8 @@ showhelp() {
 	echo "  --with-midi=midi               define which midi-player to use"
 	echo "  --with-midi-arg=arg            define which args to use for the"
 	echo "                                 midi-player"
+	echo "  --with-allegrol[=allegro-config]"
+	echo "                                 enables Allegro video driver support"
 	echo "  --with-cocoa                   enables COCOA video driver (OSX ONLY)"
 	echo "  --with-sdl[=sdl-config]        enables SDL video driver support"
 	echo "  --with-zlib[=zlib.a]           enables zlib support"
diff --git a/configure b/configure
index 9b0676af3..6e8ff6cd7 100755
--- a/configure
+++ b/configure
@@ -82,6 +82,7 @@ SRCS="`< $ROOT_DIR/source.list tr '\r' '\n' | $awk '
 
 		deep += 1;
 
+		if ($0 == "ALLEGRO"     && "'$allegro_config'" == "")      { next; }
 		if ($0 == "SDL"         && "'$sdl_config'" == "")          { next; }
 		if ($0 == "PNG"         && "'$png_config'" == "")          { next; }
 		if ($0 == "OSX"         && "'$os'" != "OSX")               { next; }
diff --git a/projects/generate b/projects/generate
index 7d97549b9..035fd0a12 100755
--- a/projects/generate
+++ b/projects/generate
@@ -28,6 +28,7 @@ fi
 
 
 # First, collect the list of Windows files
+allegro_config=""
 sdl_config="1"
 png_config="1"
 os="MSVC"
@@ -78,6 +79,7 @@ load_main_data() {
 
 			deep += 1;
 
+			if ($0 == "ALLEGRO"     && "'$allegro_config'" == "")      { next; }
 			if ($0 == "SDL"         && "'$sdl_config'" == "")          { next; }
 			if ($0 == "PNG"         && "'$png_config'" == "")          { next; }
 			if ($0 == "OSX"         && "'$os'" != "OSX")               { next; }
diff --git a/source.list b/source.list
index 961af553d..facc10586 100644
--- a/source.list
+++ b/source.list
@@ -122,6 +122,9 @@ widget.cpp
 window.cpp
 
 # Header Files
+#if ALLEGRO
+	video/allegro_v.h
+#end
 ai/ai.h
 aircraft.h
 airport.h
@@ -604,6 +607,9 @@ yapf/yapf_road.cpp
 yapf/yapf_ship.cpp
 
 # Video
+#if ALLEGRO
+	video/allegro_v.cpp
+#end
 video/dedicated_v.cpp
 video/null_v.cpp
 #if SDL
diff --git a/src/video/allegro_v.cpp b/src/video/allegro_v.cpp
new file mode 100644
index 000000000..a70a2709c
--- /dev/null
+++ b/src/video/allegro_v.cpp
@@ -0,0 +1,498 @@
+/* $Id$ */
+
+/** @file allegro_v.cpp Implementation of the Allegro video driver. */
+
+#ifdef WITH_ALLEGRO
+
+#include "../stdafx.h"
+#include "../openttd.h"
+#include "../debug.h"
+#include "../gfx_func.h"
+#include "../sdl.h"
+#include "../variables.h"
+#include "../rev.h"
+#include "../blitter/factory.hpp"
+#include "../network/network.h"
+#include "../core/math_func.hpp"
+#include "../core/random_func.hpp"
+#include "../functions.h"
+#include "../texteff.hpp"
+#include "allegro_v.h"
+#include <allegro.h>
+
+static FVideoDriver_Allegro iFVideoDriver_Allegro;
+
+static BITMAP *_allegro_screen;
+
+#define MAX_DIRTY_RECTS 100
+static PointDimension _dirty_rects[MAX_DIRTY_RECTS];
+static int _num_dirty_rects;
+
+void VideoDriver_Allegro::MakeDirty(int left, int top, int width, int height)
+{
+	if (_num_dirty_rects < MAX_DIRTY_RECTS) {
+		_dirty_rects[_num_dirty_rects].x = left;
+		_dirty_rects[_num_dirty_rects].y = top;
+		_dirty_rects[_num_dirty_rects].width = width;
+		_dirty_rects[_num_dirty_rects].height = height;
+	}
+	_num_dirty_rects++;
+}
+
+static void DrawSurfaceToScreen()
+{
+	int n = _num_dirty_rects;
+	if (n == 0) return;
+
+	_num_dirty_rects = 0;
+	if (n > MAX_DIRTY_RECTS) {
+		blit(_allegro_screen, screen, 0, 0, 0, 0, _allegro_screen->w, _allegro_screen->h);
+		return;
+	}
+
+	for (int i = 0; i < n; i++) {
+		blit(_allegro_screen, screen, _dirty_rects[i].x, _dirty_rects[i].y, _dirty_rects[i].x, _dirty_rects[i].y, _dirty_rects[i].width, _dirty_rects[i].height);
+	}
+}
+
+
+static void UpdatePalette(uint start, uint count)
+{
+	static PALETTE pal;
+
+	uint end = start + count;
+	for (uint i = start; i != end; i++) {
+		pal[i].r = _cur_palette[i].r / 4;
+		pal[i].g = _cur_palette[i].g / 4;
+		pal[i].b = _cur_palette[i].b / 4;
+		pal[i].filler = 0;
+	}
+
+	set_palette_range(pal, start, end - 1, 1);
+}
+
+static void InitPalette()
+{
+	UpdatePalette(0, 256);
+}
+
+static void CheckPaletteAnim()
+{
+	if (_pal_count_dirty != 0) {
+		Blitter *blitter = BlitterFactoryBase::GetCurrentBlitter();
+
+		switch (blitter->UsePaletteAnimation()) {
+			case Blitter::PALETTE_ANIMATION_VIDEO_BACKEND:
+				UpdatePalette(_pal_first_dirty, _pal_count_dirty);
+				break;
+
+			case Blitter::PALETTE_ANIMATION_BLITTER:
+				blitter->PaletteAnimate(_pal_first_dirty, _pal_count_dirty);
+				break;
+
+			case Blitter::PALETTE_ANIMATION_NONE:
+				break;
+
+			default:
+				NOT_REACHED();
+		}
+		_pal_count_dirty = 0;
+	}
+}
+
+static const Dimension default_resolutions[] = {
+	{ 640,  480},
+	{ 800,  600},
+	{1024,  768},
+	{1152,  864},
+	{1280,  800},
+	{1280,  960},
+	{1280, 1024},
+	{1400, 1050},
+	{1600, 1200},
+	{1680, 1050},
+	{1920, 1200}
+};
+
+static void GetVideoModes()
+{
+	/* Need to set a gfx_mode as there is NO other way to autodetect for
+	 * cards ourselves... and we need a card to get the modes. */
+	set_gfx_mode(_fullscreen ? GFX_AUTODETECT_FULLSCREEN : GFX_AUTODETECT_WINDOWED, 640, 480, 0, 0);
+
+	GFX_MODE_LIST *mode_list = get_gfx_mode_list(gfx_driver->id);
+	if (mode_list == NULL) {
+		memcpy(_resolutions, default_resolutions, sizeof(default_resolutions));
+		_num_resolutions = lengthof(default_resolutions);
+		return;
+	}
+
+	GFX_MODE *modes = mode_list->mode;
+
+	int n = 0;
+	for (int i = 0; modes[i].bpp != 0; i++) {
+		int w = modes[i].width;
+		int h = modes[i].height;
+		if (w >= 640 && h >= 480) {
+			int j;
+			for (j = 0; j < n; j++) {
+				if (_resolutions[j].width == w && _resolutions[j].height == h) break;
+			}
+
+			if (j == n) {
+				_resolutions[j].width  = w;
+				_resolutions[j].height = h;
+				if (++n == lengthof(_resolutions)) break;
+			}
+		}
+	}
+	_num_resolutions = n;
+	SortResolutions(_num_resolutions);
+
+	destroy_gfx_mode_list(mode_list);
+}
+
+static void GetAvailableVideoMode(int *w, int *h)
+{
+	/* is the wanted mode among the available modes? */
+	for (int i = 0; i != _num_resolutions; i++) {
+		if (*w == _resolutions[i].width && *h == _resolutions[i].height) return;
+	}
+
+	/* use the closest possible resolution */
+	int best = 0;
+	uint delta = abs((_resolutions[0].width - *w) * (_resolutions[0].height - *h));
+	for (int i = 1; i != _num_resolutions; ++i) {
+		uint newdelta = abs((_resolutions[i].width - *w) * (_resolutions[i].height - *h));
+		if (newdelta < delta) {
+			best = i;
+			delta = newdelta;
+		}
+	}
+	*w = _resolutions[best].width;
+	*h = _resolutions[best].height;
+}
+
+static bool CreateMainSurface(int w, int h)
+{
+	int bpp = BlitterFactoryBase::GetCurrentBlitter()->GetScreenDepth();
+	if (bpp == 0) usererror("Can't use a blitter that blits 0 bpp for normal visuals");
+	set_color_depth(bpp);
+
+	GetVideoModes();
+	GetAvailableVideoMode(&w, &h);
+	if (set_gfx_mode(_fullscreen ? GFX_AUTODETECT_FULLSCREEN : GFX_AUTODETECT_WINDOWED, w, h, 0, 0) != 0) return false;
+
+	_allegro_screen = create_bitmap(screen->w, screen->h);
+	_screen.width = screen->w;
+	_screen.height = screen->h;
+	_screen.pitch = ((byte*)screen->line[1] - (byte*)screen->line[0]) / (bitmap_color_depth(screen) / 8);
+
+	poll_mouse();
+	_cursor.pos.x = mouse_x;
+	_cursor.pos.y = mouse_y;
+
+	InitPalette();
+
+	char caption[32];
+	snprintf(caption, sizeof(caption), "OpenTTD %s", _openttd_revision);
+	set_window_title(caption);
+
+	GameSizeChanged();
+
+	return true;
+}
+
+struct VkMapping {
+	uint16 vk_from;
+	byte vk_count;
+	byte map_to;
+};
+
+#define AS(x, z) {x, 0, z}
+#define AM(x, y, z, w) {x, y - x, z}
+
+static const VkMapping _vk_mapping[] = {
+	/* Pageup stuff + up/down */
+	AM(KEY_PGUP, KEY_PGDN, WKC_PAGEUP, WKC_PAGEDOWN),
+	AS(KEY_UP,     WKC_UP),
+	AS(KEY_DOWN,   WKC_DOWN),
+	AS(KEY_LEFT,   WKC_LEFT),
+	AS(KEY_RIGHT,  WKC_RIGHT),
+
+	AS(KEY_HOME,   WKC_HOME),
+	AS(KEY_END,    WKC_END),
+
+	AS(KEY_INSERT, WKC_INSERT),
+	AS(KEY_DEL,    WKC_DELETE),
+
+	/* Map letters & digits */
+	AM(KEY_A, KEY_Z, 'A', 'Z'),
+	AM(KEY_0, KEY_9, '0', '9'),
+
+	AS(KEY_ESC,       WKC_ESC),
+	AS(KEY_PAUSE,     WKC_PAUSE),
+	AS(KEY_BACKSPACE, WKC_BACKSPACE),
+
+	AS(KEY_SPACE,     WKC_SPACE),
+	AS(KEY_ENTER,     WKC_RETURN),
+	AS(KEY_TAB,       WKC_TAB),
+
+	/* Function keys */
+	AM(KEY_F1, KEY_F12, WKC_F1, WKC_F12),
+
+	/* Numeric part. */
+	AM(KEY_0_PAD, KEY_9_PAD, '0', '9'),
+	AS(KEY_SLASH_PAD,   WKC_NUM_DIV),
+	AS(KEY_ASTERISK,    WKC_NUM_MUL),
+	AS(KEY_MINUS_PAD,   WKC_NUM_MINUS),
+	AS(KEY_PLUS_PAD,    WKC_NUM_PLUS),
+	AS(KEY_ENTER_PAD,   WKC_NUM_ENTER),
+	AS(KEY_DEL_PAD,     WKC_DELETE),
+
+	/* Other non-letter keys */
+	AS(KEY_SLASH,        WKC_SLASH),
+	AS(KEY_SEMICOLON,    WKC_SEMICOLON),
+	AS(KEY_EQUALS,       WKC_EQUALS),
+	AS(KEY_OPENBRACE,    WKC_L_BRACKET),
+	AS(KEY_BACKSLASH,    WKC_BACKSLASH),
+	AS(KEY_CLOSEBRACE,   WKC_R_BRACKET),
+
+	AS(KEY_QUOTE,   WKC_SINGLEQUOTE),
+	AS(KEY_COMMA,   WKC_COMMA),
+	AS(KEY_MINUS,   WKC_MINUS),
+	AS(KEY_STOP,    WKC_PERIOD),
+	AS(KEY_TILDE,   WKC_BACKQUOTE),
+};
+
+static uint32 ConvertAllegroKeyIntoMy()
+{
+	int scancode;
+	int unicode = ureadkey(&scancode);
+
+	const VkMapping *map;
+	uint key = 0;
+
+	for (map = _vk_mapping; map != endof(_vk_mapping); ++map) {
+		if ((uint)(scancode - map->vk_from) <= map->vk_count) {
+			key = scancode - map->vk_from + map->map_to;
+			break;
+		}
+	}
+
+	if (key_shifts & KB_SHIFT_FLAG) key |= WKC_SHIFT;
+	if (key_shifts & KB_CTRL_FLAG)  key |= WKC_CTRL;
+	if (key_shifts & KB_ALT_FLAG)   key |= WKC_ALT;
+#if 0
+	DEBUG(driver, 0, "Scancode character pressed %u", scancode);
+	DEBUG(driver, 0, "Unicode character pressed %u", unicode);
+#endif
+	return (key << 16) + unicode;
+}
+
+enum {
+	LEFT_BUTTON,
+	RIGHT_BUTTON,
+};
+
+static void PollEvent()
+{
+	poll_mouse();
+
+	bool mouse_action = false;
+
+	/* Mouse buttons */
+	static int prev_button_state;
+	if (prev_button_state != mouse_b) {
+		uint diff = prev_button_state ^ mouse_b;
+		while (diff != 0) {
+			int button = FindFirstBit(diff);
+			ClrBit(diff, button);
+			if (HasBit(mouse_b, button)) {
+				/* Pressed mouse button */
+				if (_rightclick_emulate && key_shifts & KB_CTRL_FLAG) {
+					button = RIGHT_BUTTON;
+					ClrBit(diff, RIGHT_BUTTON);
+				}
+				switch (button) {
+					case LEFT_BUTTON:
+						_left_button_down = true;
+						break;
+
+					case RIGHT_BUTTON:
+						_right_button_down = true;
+						_right_button_clicked = true;
+						break;
+
+					default:
+						/* ignore rest */
+						break;
+				}
+			} else {
+				/* Released mouse button */
+				if (_rightclick_emulate) {
+					_right_button_down = false;
+					_left_button_down = false;
+					_left_button_clicked = false;
+				} else if (button == LEFT_BUTTON) {
+					_left_button_down = false;
+					_left_button_clicked = false;
+				} else if (button == RIGHT_BUTTON) {
+					_right_button_down = false;
+				}
+			}
+		}
+		prev_button_state = mouse_b;
+		mouse_action = true;
+	}
+
+	/* Mouse movement */
+	int dx = mouse_x - _cursor.pos.x;
+	int dy = mouse_y - _cursor.pos.y;
+	if (dx != 0 || dy != 0) {
+		if (_cursor.fix_at) {
+			_cursor.delta.x += dx;
+			_cursor.delta.y += dy;
+			position_mouse(_cursor.pos.x, _cursor.pos.y);
+		} else {
+			_cursor.delta.x = dx;
+			_cursor.delta.y = dy;
+			_cursor.pos.x = mouse_x;
+			_cursor.pos.y = mouse_y;
+			_cursor.dirty = true;
+		}
+		mouse_action = true;
+	}
+
+	if (mouse_action) HandleMouseEvents();
+
+	poll_keyboard();
+	if (key_shifts & KB_ALT_FLAG && (key[KEY_ENTER] || key[KEY_F])) {
+		ToggleFullScreen(!_fullscreen);
+	} else if (keypressed()) {
+		HandleKeypress(ConvertAllegroKeyIntoMy());
+	}
+}
+
+const char *VideoDriver_Allegro::Start(const char * const *parm)
+{
+	if (install_allegro(SYSTEM_AUTODETECT, &errno, NULL)) return NULL;
+
+	install_timer();
+	install_mouse();
+	install_keyboard();
+
+	CreateMainSurface(_cur_resolution.width, _cur_resolution.height);
+	MarkWholeScreenDirty();
+	set_close_button_callback(HandleExitGameRequest);
+
+	return NULL;
+}
+
+void VideoDriver_Allegro::Stop()
+{
+	allegro_exit();
+}
+
+#if defined(UNIX) || defined(__OS2__) || defined(PSP)
+# include <sys/time.h> /* gettimeofday */
+
+static uint32 GetTime()
+{
+	struct timeval tim;
+
+	gettimeofday(&tim, NULL);
+	return tim.tv_usec / 1000 + tim.tv_sec * 1000;
+}
+#else
+static uint32 GetTime()
+{
+	return GetTickCount();
+}
+#endif
+
+
+void VideoDriver_Allegro::MainLoop()
+{
+	uint32 cur_ticks = GetTime();
+	uint32 last_cur_ticks = cur_ticks;
+	uint32 next_tick = cur_ticks + 30;
+	uint32 pal_tick = 0;
+
+	for (;;) {
+		uint32 prev_cur_ticks = cur_ticks; // to check for wrapping
+		InteractiveRandom(); // randomness
+
+		PollEvent();
+		if (_exit_game) return;
+
+#if defined(_DEBUG)
+		if (_shift_pressed)
+#else
+		/* Speedup when pressing tab, except when using ALT+TAB
+		 * to switch to another application */
+		if (keys[KEY_TAB] && (key_shifts & KB_ALT_FLAG) == 0)
+#endif
+		{
+			if (!_networking && _game_mode != GM_MENU) _fast_forward |= 2;
+		} else if (_fast_forward & 2) {
+			_fast_forward = 0;
+		}
+
+		cur_ticks = GetTime();
+		if (cur_ticks >= next_tick || (_fast_forward && !_pause_game) || cur_ticks < prev_cur_ticks) {
+			_realtime_tick += cur_ticks - last_cur_ticks;
+			last_cur_ticks = cur_ticks;
+			next_tick = cur_ticks + 30;
+
+			bool old_ctrl_pressed = _ctrl_pressed;
+
+			_ctrl_pressed  = !!(key_shifts & KB_CTRL_FLAG);
+			_shift_pressed = !!(key_shifts & KB_SHIFT_FLAG);
+
+			/* determine which directional keys are down */
+			_dirkeys =
+				(key[KEY_LEFT]  ? 1 : 0) |
+				(key[KEY_UP]    ? 2 : 0) |
+				(key[KEY_RIGHT] ? 4 : 0) |
+				(key[KEY_DOWN]  ? 8 : 0);
+
+			if (old_ctrl_pressed != _ctrl_pressed) HandleCtrlChanged();
+
+			GameLoop();
+
+			_screen.dst_ptr = _allegro_screen->line[0];
+			UpdateWindows();
+			if (++pal_tick > 4) {
+				CheckPaletteAnim();
+				pal_tick = 1;
+			}
+			DrawSurfaceToScreen();
+		} else {
+			CSleep(1);
+			_screen.dst_ptr = _allegro_screen->line[0];
+			NetworkDrawChatMessage();
+			DrawMouseCursor();
+			DrawSurfaceToScreen();
+		}
+	}
+}
+
+bool VideoDriver_Allegro::ChangeResolution(int w, int h)
+{
+	return CreateMainSurface(w, h);
+}
+
+bool VideoDriver_Allegro::ToggleFullscreen(bool fullscreen)
+{
+	_fullscreen = fullscreen;
+	GetVideoModes(); // get the list of available video modes
+	if (_num_resolutions == 0 || !this->ChangeResolution(_cur_resolution.width, _cur_resolution.height)) {
+		/* switching resolution failed, put back full_screen to original status */
+		_fullscreen ^= true;
+		return false;
+	}
+	return true;
+}
+
+#endif /* WITH_ALLEGRO */
diff --git a/src/video/allegro_v.h b/src/video/allegro_v.h
new file mode 100644
index 000000000..6f420c732
--- /dev/null
+++ b/src/video/allegro_v.h
@@ -0,0 +1,33 @@
+/* $Id$ */
+
+/** @file allegro_v.h Base of the Allegro video driver. */
+
+#ifndef VIDEO_ALLEGRO_H
+#define VIDEO_ALLEGRO_H
+
+#include "video_driver.hpp"
+
+class VideoDriver_Allegro: public VideoDriver {
+public:
+	/* virtual */ const char *Start(const char * const *param);
+
+	/* virtual */ void Stop();
+
+	/* virtual */ void MakeDirty(int left, int top, int width, int height);
+
+	/* virtual */ void MainLoop();
+
+	/* virtual */ bool ChangeResolution(int w, int h);
+
+	/* virtual */ bool ToggleFullscreen(bool fullscreen);
+};
+
+class FVideoDriver_Allegro: public VideoDriverFactory<FVideoDriver_Allegro> {
+public:
+	static const int priority = 5;
+	/* virtual */ const char *GetName() { return "allegro"; }
+	/* virtual */ const char *GetDescription() { return "Allegro Video Driver"; }
+	/* virtual */ Driver *CreateInstance() { return new VideoDriver_Allegro(); }
+};
+
+#endif /* VIDEO_ALLEGRO_H */