(svn r26522) -Add: A config-file-only setting to disable usage of 8bpp video modes.

-Remove: [win32] fullscreen_bpp setting, which is replaced by above setting.
-Change: Disable usage of 8bpp blitters and video modes by default. Many modern OS and hardware cause issues with those.

src/gfx.cpp

@@ -30,6 +30,7 @@
 
 byte _dirkeys;        ///< 1 = left, 2 = up, 4 = right, 8 = down
 bool _fullscreen;
+byte _support8bpp;
 CursorVars _cursor;
 bool _ctrl_pressed;   ///< Is Ctrl pressed?
 bool _shift_pressed;  ///< Is Shift pressed?

src/gfx_func.h

@@ -52,6 +52,7 @@ void CreateConsole();
 
 extern byte _dirkeys;        ///< 1 = left, 2 = up, 4 = right, 8 = down
 extern bool _fullscreen;
+extern byte _support8bpp;
 extern CursorVars _cursor;
 extern bool _ctrl_pressed;   ///< Is Ctrl pressed?
 extern bool _shift_pressed;  ///< Is Shift pressed?

src/gfx_type.h

@@ -300,4 +300,11 @@ struct Palette {
 	int count_dirty;     ///< The number of dirty elements.
 };
 
+/** Modes for 8bpp support */
+enum Support8bpp {
+	S8BPP_NONE = 0, ///< No support for 8bpp by OS or hardware, force 32bpp blitters.
+	S8BPP_SYSTEM,   ///< No 8bpp support by hardware, do not try to use 8bpp video modes or hardware palettes.
+	S8BPP_HARDWARE, ///< Full 8bpp support by OS and hardware.
+};
+
 #endif /* GFX_TYPE_H */

src/gfxinit.cpp

@@ -238,16 +238,21 @@ static bool SwitchNewGRFBlitter()
 	/* Null driver => dedicated server => do nothing. */
 	if (BlitterFactory::GetCurrentBlitter()->GetScreenDepth() == 0) return false;
 
-	/* Get preferred depth. */
+	/* Get preferred depth.
+	 *  - depth_wanted_by_base: Depth required by the baseset, i.e. the majority of the sprites.
+	 *  - depth_wanted_by_grf:  Depth required by some NewGRF.
+	 * Both can force using a 32bpp blitter. depth_wanted_by_base is used to select
+	 * between multiple 32bpp blitters, which perform differently with 8bpp sprites.
+	 */
 	uint depth_wanted_by_base = BaseGraphics::GetUsedSet()->blitter == BLT_32BPP ? 32 : 8;
-	uint depth_wanted_by_grf = 8;
+	uint depth_wanted_by_grf = _support8bpp == S8BPP_NONE ? 32 : 8;
 	for (GRFConfig *c = _grfconfig; c != NULL; c = c->next) {
 		if (c->status == GCS_DISABLED || c->status == GCS_NOT_FOUND || HasBit(c->flags, GCF_INIT_ONLY)) continue;
 		if (c->palette & GRFP_BLT_32BPP) depth_wanted_by_grf = 32;
 	}
 
 	/* Search the best blitter. */
-	struct {
+	static const struct {
 		const char *name;
 		uint animation; ///< 0: no support, 1: do support, 2: both
 		uint min_base_depth, max_base_depth, min_grf_depth, max_grf_depth;

src/openttd.cpp

@@ -757,8 +757,15 @@ int openttd_main(int argc, char *argv[])
 	DEBUG(misc, 1, "Loading blitter...");
 	if (blitter == NULL && _ini_blitter != NULL) blitter = stredup(_ini_blitter);
 	_blitter_autodetected = StrEmpty(blitter);
-	/* If we have a 32 bpp base set, try to select the 32 bpp blitter first, but only if we autoprobe the blitter. */
-	if (!_blitter_autodetected || BaseGraphics::GetUsedSet() == NULL || BaseGraphics::GetUsedSet()->blitter == BLT_8BPP || BlitterFactory::SelectBlitter("32bpp-anim") == NULL) {
+	/* Activate the initial blitter.
+	 * This is only some initial guess, after NewGRFs have been loaded SwitchNewGRFBlitter may switch to a different one.
+	 *  - Never guess anything, if the user specified a blitter. (_blitter_autodetected)
+	 *  - Use 32bpp blitter if baseset or 8bpp-support settings says so.
+	 *  - Use 8bpp blitter otherwise.
+	 */
+	if (!_blitter_autodetected ||
+			(_support8bpp != S8BPP_NONE && (BaseGraphics::GetUsedSet() == NULL || BaseGraphics::GetUsedSet()->blitter == BLT_8BPP)) ||
+			BlitterFactory::SelectBlitter("32bpp-anim") == NULL) {
 		if (BlitterFactory::SelectBlitter(blitter) == NULL) {
 			StrEmpty(blitter) ?
 				usererror("Failed to autoprobe blitter") :

src/table/misc_settings.ini

@@ -9,12 +9,15 @@
 [pre-amble]
 extern char _config_language_file[MAX_PATH];
 
+static const char *_support8bppmodes = "no|system|hardware";
+
 static const SettingDescGlobVarList _misc_settings[] = {
 [post-amble]
 };
 [templates]
 SDTG_LIST  =  SDTG_LIST($name, $type, $length, $flags, $guiflags, $var, $def,                               $str, $strhelp, $strval, $proc, $from, $to, $cat),
 SDTG_MMANY = SDTG_MMANY($name, $type,          $flags, $guiflags, $var, $def,                        $full, $str, $strhelp, $strval, $proc, $from, $to, $cat),
+SDTG_OMANY = SDTG_OMANY($name, $type,          $flags, $guiflags, $var, $def,       $max,            $full, $str, $strhelp, $strval, $proc, $from, $to, $cat),
 SDTG_STR   =   SDTG_STR($name, $type,          $flags, $guiflags, $var, $def,                               $str, $strhelp, $strval, $proc, $from, $to, $cat),
 SDTG_BOOL  =  SDTG_BOOL($name,                 $flags, $guiflags, $var, $def,                               $str, $strhelp, $strval, $proc, $from, $to, $cat),
 SDTG_VAR   =   SDTG_VAR($name, $type,          $flags, $guiflags, $var, $def, $min, $max, $interval,        $str, $strhelp, $strval, $proc, $from, $to, $cat),
@@ -48,6 +51,15 @@ var      = _fullscreen
 def      = false
 cat      = SC_BASIC
 
+[SDTG_OMANY]
+name     = ""support8bpp""
+type     = SLE_UINT8
+var      = _support8bpp
+def      = 0
+max      = 2
+full     = _support8bppmodes
+cat      = SC_BASIC
+
 [SDTG_STR]
 name     = ""graphicsset""
 type     = SLE_STRQ

src/table/win32_settings.ini

@@ -10,7 +10,7 @@
 /* win32_v.cpp only settings */
 #if defined(WIN32) && !defined(DEDICATED)
 extern bool _force_full_redraw, _window_maximize;
-extern uint _display_hz, _fullscreen_bpp;
+extern uint _display_hz;
 
 static const SettingDescGlobVarList _win32_settings[] = {
 [post-amble]
@@ -51,15 +51,6 @@ var      = _force_full_redraw
 def      = false
 cat      = SC_EXPERT
 
-[SDTG_VAR]
-name     = ""fullscreen_bpp""
-type     = SLE_UINT
-var      = _fullscreen_bpp
-def      = 8
-min      = 8
-max      = 32
-cat      = SC_EXPERT
-
 [SDTG_BOOL]
 name     = ""window_maximize""
 var      = _window_maximize

src/video/sdl_v.cpp

@@ -317,7 +317,7 @@ bool VideoDriver_SDL::CreateMainSurface(uint w, uint h)
 		 * (which we can't force in 8bpp on 8bpp mode,
 		 * unfortunately).
 		 */
-		want_hwpalette = (bpp == 8 && _fullscreen);
+		want_hwpalette = bpp == 8 && _fullscreen && _support8bpp == S8BPP_HARDWARE;
 	} else {
 		/* User specified a value manually */
 		want_hwpalette = _use_hwpalette;

src/video/win32_v.cpp

@@ -52,7 +52,6 @@ static struct {
 bool _force_full_redraw;
 bool _window_maximize;
 uint _display_hz;
-uint _fullscreen_bpp;
 static Dimension _bck_resolution;
 #if !defined(WINCE) || _WIN32_WCE >= 0x400
 DWORD _imm_props;
@@ -272,23 +271,21 @@ bool VideoDriver_Win32::MakeWindow(bool full_screen)
 	if (full_screen) {
 		DEVMODE settings;
 
-		/* Make sure we are always at least the screen-depth of the blitter */
-		if (_fullscreen_bpp < BlitterFactory::GetCurrentBlitter()->GetScreenDepth()) _fullscreen_bpp = BlitterFactory::GetCurrentBlitter()->GetScreenDepth();
-
 		memset(&settings, 0, sizeof(settings));
 		settings.dmSize = sizeof(settings);
 		settings.dmFields =
-			(_fullscreen_bpp != 0 ? DM_BITSPERPEL : 0) |
+			DM_BITSPERPEL |
 			DM_PELSWIDTH |
 			DM_PELSHEIGHT |
 			(_display_hz != 0 ? DM_DISPLAYFREQUENCY : 0);
-		settings.dmBitsPerPel = _fullscreen_bpp;
+		settings.dmBitsPerPel = BlitterFactory::GetCurrentBlitter()->GetScreenDepth();
 		settings.dmPelsWidth  = _wnd.width_org;
 		settings.dmPelsHeight = _wnd.height_org;
 		settings.dmDisplayFrequency = _display_hz;
 
 		/* Check for 8 bpp support. */
-		if (settings.dmBitsPerPel != 32 && ChangeDisplaySettings(&settings, CDS_FULLSCREEN | CDS_TEST) != DISP_CHANGE_SUCCESSFUL) {
+		if (settings.dmBitsPerPel == 8 &&
+				(_support8bpp != S8BPP_HARDWARE || ChangeDisplaySettings(&settings, CDS_FULLSCREEN | CDS_TEST) != DISP_CHANGE_SUCCESSFUL)) {
 			settings.dmBitsPerPel = 32;
 		}
 
@@ -1107,11 +1104,14 @@ static void FindResolutions()
 	uint i;
 	DEVMODEA dm;
 
+	/* Check modes for the relevant fullscreen bpp */
+	int bpp = _support8bpp != S8BPP_HARDWARE ? 32 : BlitterFactory::GetCurrentBlitter()->GetScreenDepth();
+
 	/* XXX - EnumDisplaySettingsW crashes with unicows.dll on Windows95
 	 * Doesn't really matter since we don't pass a string anyways, but still
 	 * a letdown */
 	for (i = 0; EnumDisplaySettingsA(NULL, i, &dm) != 0; i++) {
-		if (dm.dmBitsPerPel == BlitterFactory::GetCurrentBlitter()->GetScreenDepth() &&
+		if (dm.dmBitsPerPel == bpp &&
 				dm.dmPelsWidth >= 640 && dm.dmPelsHeight >= 480) {
 			uint j;