Got rid of OSystem::colorToRGB and RGBToColor; added implementations for OSystem::getOverlayFormat to several ports (pending testing by the porters)

svn-id: r34912

31 files changed, 37 insertions, 179 deletions

diff --git a/backends/platform/PalmOS/Src/base_gfx.cpp b/backends/platform/PalmOS/Src/base_gfx.cpp
index c96a258d52..cb40bb55e5 100644
--- a/backends/platform/PalmOS/Src/base_gfx.cpp
+++ b/backends/platform/PalmOS/Src/base_gfx.cpp
@@ -152,7 +152,7 @@ void OSystem_PalmBase::updateScreen() {
 
 void OSystem_PalmBase::clearScreen() {
 	WinSetDrawWindow(WinGetDisplayWindow());
-	WinSetBackColor(RGBToColor(0,0,0));
+	WinSetBackColor(Graphics::RGBToColor<ColorMasks<565> >(0,0,0));
 	WinEraseWindow();
 }
 
diff --git a/backends/platform/PalmOS/Src/be_base.h b/backends/platform/PalmOS/Src/be_base.h
index 03a9d56fb4..009c5a9997 100644
--- a/backends/platform/PalmOS/Src/be_base.h
+++ b/backends/platform/PalmOS/Src/be_base.h
@@ -230,8 +230,7 @@ public:
 
 	void setPalette(const byte *colors, uint start, uint num);
 	void grabPalette(byte *colors, uint start, uint num);
-	virtual OverlayColor RGBToColor(uint8 r, uint8 g, uint8 b) = 0;
-	virtual void colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b) = 0;
+	virtual Graphics::PixelFormat getOverlayFormat() const { return Graphics::createPixelFormat<565>(); }
 
 	bool pollEvent(Common::Event &event);
 
diff --git a/backends/platform/PalmOS/Src/be_os5.h b/backends/platform/PalmOS/Src/be_os5.h
index 99d1dd9dc1..c56688b98f 100644
--- a/backends/platform/PalmOS/Src/be_os5.h
+++ b/backends/platform/PalmOS/Src/be_os5.h
@@ -181,8 +181,6 @@ public:
 	virtual void clearOverlay();
 	virtual void grabOverlay(OverlayColor *buf, int pitch);
 	virtual void copyRectToOverlay(const OverlayColor *buf, int pitch, int x, int y, int w, int h);
-	virtual OverlayColor RGBToColor(uint8 r, uint8 g, uint8 b);
-	virtual void colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b);
 
 	void setWindowCaption(const char *caption);
 
diff --git a/backends/platform/PalmOS/Src/be_zodiac.h b/backends/platform/PalmOS/Src/be_zodiac.h
index 58e2ca88ac..28fcf29ddd 100644
--- a/backends/platform/PalmOS/Src/be_zodiac.h
+++ b/backends/platform/PalmOS/Src/be_zodiac.h
@@ -71,8 +71,6 @@ public:
 	void clearOverlay();
 	void grabOverlay(OverlayColor *buf, int pitch);
 	void copyRectToOverlay(const OverlayColor *buf, int pitch, int x, int y, int w, int h);
-	OverlayColor RGBToColor(uint8 r, uint8 g, uint8 b);
-	void colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b);
 };
 
 #endif
diff --git a/backends/platform/PalmOS/Src/os5_gfx.cpp b/backends/platform/PalmOS/Src/os5_gfx.cpp
index 2d26419dff..c02e1f7db4 100644
--- a/backends/platform/PalmOS/Src/os5_gfx.cpp
+++ b/backends/platform/PalmOS/Src/os5_gfx.cpp
@@ -77,8 +77,8 @@ void OSystem_PalmOS5::load_gfx_mode() {
 		__68K(PINSetInputTriggerState(pinInputTriggerDisabled));
 	}
 
-	gVars->indicator.on = RGBToColor(0,255,0);
-	gVars->indicator.off = RGBToColor(0,0,0);
+	gVars->indicator.on = Graphics::RGBToColor<ColorMasks<565> >(0,255,0);
+	gVars->indicator.off = Graphics::RGBToColor<ColorMasks<565> >(0,0,0);
 
 	_overlayH =  alloc_screen(_screenWidth, _screenHeight);
 	_overlayP = (OverlayColor *)(BmpGetBits(WinGetBitmap(_overlayH)));
diff --git a/backends/platform/PalmOS/Src/os5_overlay.cpp b/backends/platform/PalmOS/Src/os5_overlay.cpp
index 5555c7ef08..2ffc082547 100644
--- a/backends/platform/PalmOS/Src/os5_overlay.cpp
+++ b/backends/platform/PalmOS/Src/os5_overlay.cpp
@@ -74,13 +74,3 @@ void OSystem_PalmOS5::copyRectToOverlay(const OverlayColor *buf, int pitch, int
 		buf += pitch;
 	} while (--h);
 }
-
-OverlayColor OSystem_PalmOS5::RGBToColor(uint8 r, uint8 g, uint8 b) {
-	return gfxMakeDisplayRGB(r, g, b);
-}
-
-void OSystem_PalmOS5::colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b) {
-	r = ((color >> 8) & 0xF8);
-	g = ((color >> 3) & 0xFC);
-	b = ((color << 3) & 0xF8);
-}
diff --git a/backends/platform/PalmOS/Src/zodiac_gfx.cpp b/backends/platform/PalmOS/Src/zodiac_gfx.cpp
index e7f7adb773..866ee086f7 100644
--- a/backends/platform/PalmOS/Src/zodiac_gfx.cpp
+++ b/backends/platform/PalmOS/Src/zodiac_gfx.cpp
@@ -71,8 +71,8 @@ void OSystem_PalmZodiac::load_gfx_mode() {
 	SysSetOrientationTriggerState(sysOrientationTriggerDisabled);
 	PINSetInputTriggerState(pinInputTriggerDisabled);
 
-	gVars->indicator.on = RGBToColor(0,255,0);
-	gVars->indicator.off = RGBToColor(0,0,0);
+	gVars->indicator.on = Graphics::RGBToColor<ColorMasks<565> >(0,255,0);
+	gVars->indicator.off = Graphics::RGBToColor<ColorMasks<565> >(0,0,0);
 
 	_screenH = WinGetDisplayWindow();
 	_screenP = (byte *)BmpGetBits(WinGetBitmap(_screenH));
diff --git a/backends/platform/PalmOS/Src/zodiac_overlay.cpp b/backends/platform/PalmOS/Src/zodiac_overlay.cpp
index 34390853fc..f8322e8fa5 100644
--- a/backends/platform/PalmOS/Src/zodiac_overlay.cpp
+++ b/backends/platform/PalmOS/Src/zodiac_overlay.cpp
@@ -65,13 +65,3 @@ void OSystem_PalmZodiac::copyRectToOverlay(const OverlayColor *buf, int pitch, i
 	};
 	e = TwGfxDrawBitmap(_overlayP, &pos, &bmp);
 }
-
-OverlayColor OSystem_PalmZodiac::RGBToColor(uint8 r, uint8 g, uint8 b) {
-	return TwGfxMakeDisplayRGB(r, g, b);
-}
-
-void OSystem_PalmZodiac::colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b) {
-	r = ((color >> 8) & 0xF8);
-	g = ((color >> 3) & 0xFC);
-	b = ((color << 3) & 0xF8);
-}
diff --git a/backends/platform/dc/dc.h b/backends/platform/dc/dc.h
index 8b99457310..f8e16a4d4f 100644
--- a/backends/platform/dc/dc.h
+++ b/backends/platform/dc/dc.h
@@ -155,12 +155,7 @@ class OSystem_Dreamcast : public OSystem, public FilesystemFactory {
   void clearOverlay();
   void grabOverlay(int16 *buf, int pitch);
   void copyRectToOverlay(const int16 *buf, int pitch, int x, int y, int w, int h);
-  OverlayColor RGBToColor(uint8 r, uint8 g, uint8 b) { return (0xf000|((r&0xf0)<<4)|(g&0xf0)|(b>>4); }
-  void colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b) {
-    r = ((color>>4)&0xf0)|((color>>8)&0x0f);
-    g = (color&0xf0)|((color>>4)&0x0f);
-    b = ((color<<4)&0xf0)|(color&0x0f);
-  }
+  virtual Graphics::PixelFormat getOverlayFormat() const { return Graphics::createPixelFormat<4444>(); }
 
   // Mutex handling
   MutexRef createMutex();
diff --git a/backends/platform/ds/arm9/source/osystem_ds.h b/backends/platform/ds/arm9/source/osystem_ds.h
index 16c8f41491..27adf88198 100644
--- a/backends/platform/ds/arm9/source/osystem_ds.h
+++ b/backends/platform/ds/arm9/source/osystem_ds.h
@@ -113,9 +113,7 @@ public:
 	virtual void copyRectToOverlay(const OverlayColor *buf, int pitch, int x, int y, int w, int h);
 	virtual int16 getOverlayHeight();
 	virtual int16 getOverlayWidth();
-
-	inline virtual OverlayColor RGBToColor(uint8 r, uint8 g, uint8 b);
-	inline virtual void colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b);
+	virtual Graphics::PixelFormat getOverlayFormat() const { return Graphics::createPixelFormat<1555>(); }
 	
 	virtual bool showMouse(bool visible);
 
@@ -190,19 +188,4 @@ static const OSystem::GraphicsMode s_supportedGraphicsModes[] = {
 	{0, 0, 0},
 };
 
-OverlayColor OSystem_DS::RGBToColor(uint8 r, uint8 g, uint8 b)
-{
-	return 0x8000 | (r >> 3) | ((g >> 3) << 5) | ((b >> 3) << 10);
-	//consolePrintf("rgbtocol\n");
-	//return 0;
-}
-
-void OSystem_DS::colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b)
-{
-	r = (color & 0x001F) << 3;
-	g = ((color & 0x03E0) >> 5) << 3;
-	b = ((color & 0x7C00) >> 10) << 3;
-	//consolePrintf("coltorgb\n");
-}
-
 #endif
diff --git a/backends/platform/gp2x/gp2x-common.h b/backends/platform/gp2x/gp2x-common.h
index 063696548c..de305923a0 100644
--- a/backends/platform/gp2x/gp2x-common.h
+++ b/backends/platform/gp2x/gp2x-common.h
@@ -163,11 +163,6 @@ public:
 	int16 getOverlayHeight()  { return _overlayHeight; }
 	int16 getOverlayWidth()   { return _overlayWidth; }
 
-	// Methods that convert RGB to/from colors suitable for the overlay.
-	OverlayColor RGBToColor(uint8 r, uint8 g, uint8 b);
-	void colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b);
-
-
 	const GraphicsMode *getSupportedGraphicsModes() const;
 	int getDefaultGraphicsMode() const;
 	bool setGraphicsMode(int mode);
diff --git a/backends/platform/gp2x/graphics.cpp b/backends/platform/gp2x/graphics.cpp
index 2f16cf7068..7fa0fddeb1 100644
--- a/backends/platform/gp2x/graphics.cpp
+++ b/backends/platform/gp2x/graphics.cpp
@@ -1160,14 +1160,6 @@ void OSystem_GP2X::copyRectToOverlay(const OverlayColor *buf, int pitch, int x,
 	SDL_UnlockSurface(_overlayscreen);
 }
 
-OverlayColor OSystem_GP2X::RGBToColor(uint8 r, uint8 g, uint8 b) {
-	return SDL_MapRGB(_overlayscreen->format, r, g, b);
-}
-
-void OSystem_GP2X::colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b) {
-	SDL_GetRGB(color, _overlayscreen->format, &r, &g, &b);
-}
-
 
 #pragma mark -
 #pragma mark --- Mouse ---
diff --git a/backends/platform/iphone/osys_iphone.cpp b/backends/platform/iphone/osys_iphone.cpp
index 6ca5a52928..d5c126e73b 100644
--- a/backends/platform/iphone/osys_iphone.cpp
+++ b/backends/platform/iphone/osys_iphone.cpp
@@ -180,7 +180,7 @@ void OSystem_IPHONE::setPalette(const byte *colors, uint start, uint num) {
 	const byte *b = colors;
 
 	for (uint i = start; i < start + num; ++i) {
-		_palette[i] = RGBToColor(b[0], b[1], b[2]);
+		_palette[i] = Graphics::RGBToColor<ColorMasks<565> >(b[0], b[1], b[2]);
 		b += 4;
 	}
 
diff --git a/backends/platform/iphone/osys_iphone.h b/backends/platform/iphone/osys_iphone.h
index c743039860..c3d62b7c9c 100644
--- a/backends/platform/iphone/osys_iphone.h
+++ b/backends/platform/iphone/osys_iphone.h
@@ -143,6 +143,7 @@ public:
 	virtual void copyRectToOverlay(const OverlayColor *buf, int pitch, int x, int y, int w, int h);
 	virtual int16 getOverlayHeight();
 	virtual int16 getOverlayWidth();
+	virtual Graphics::PixelFormat getOverlayFormat() const { return Graphics::createPixelFormat<565>(); }
 
 	virtual bool showMouse(bool visible);
 
diff --git a/backends/platform/null/null.cpp b/backends/platform/null/null.cpp
index 610f1d3a42..456ee12539 100644
--- a/backends/platform/null/null.cpp
+++ b/backends/platform/null/null.cpp
@@ -91,9 +91,7 @@ public:
 	virtual void copyRectToOverlay(const OverlayColor *buf, int pitch, int x, int y, int w, int h);
 	virtual int16 getOverlayHeight();
 	virtual int16 getOverlayWidth();
-
-	virtual OverlayColor RGBToColor(uint8 r, uint8 g, uint8 b);
-	virtual void colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b);
+	virtual Graphics::PixelFormat getOverlayFormat() const { return Graphics::createPixelFormat<565>(); }
 
 	virtual bool showMouse(bool visible);
 
@@ -257,12 +255,6 @@ int16 OSystem_NULL::getOverlayWidth() {
 	return getWidth();
 }
 
-OverlayColor OSystem_NULL::RGBToColor(uint8 r, uint8 g, uint8 b) {
-	return 0;
-}
-
-void OSystem_NULL::colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b) {
-}
 
 bool OSystem_NULL::showMouse(bool visible) {
 	return true;
diff --git a/backends/platform/ps2/systemps2.cpp b/backends/platform/ps2/systemps2.cpp
index 85eb303e86..aac399ee23 100644
--- a/backends/platform/ps2/systemps2.cpp
+++ b/backends/platform/ps2/systemps2.cpp
@@ -641,16 +641,6 @@ bool OSystem_PS2::pollEvent(Common::Event &event) {
 	return res;
 }
 
-OverlayColor OSystem_PS2::RGBToColor(uint8 r, uint8 g, uint8 b) {
-	return (r >> 3) | ((g >> 3) << 5) | ((b >> 3) << 10);
-}
-
-void OSystem_PS2::colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b) {
-	r = (color & 0x1F) << 3;
-	g = ((color >> 5) & 0x1F) << 3;
-	b = ((color >> 10) & 0x1F) << 3;
-}
-
 int16 OSystem_PS2::getHeight(void) {
 	return _screen->getHeight();
 }
diff --git a/backends/platform/ps2/systemps2.h b/backends/platform/ps2/systemps2.h
index 9539baf4f5..e4ac410caa 100644
--- a/backends/platform/ps2/systemps2.h
+++ b/backends/platform/ps2/systemps2.h
@@ -110,9 +110,7 @@ public:
 	virtual Common::SeekableReadStream *openConfigFileForReading();
 	virtual Common::WriteStream *openConfigFileForWriting();
 
-	virtual OverlayColor RGBToColor(uint8 r, uint8 g, uint8 b);
-
-	virtual void colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b);
+	virtual Graphics::PixelFormat getOverlayFormat() const { return Graphics::createPixelFormat<555>(); }
 
 	virtual Common::SaveFileManager *getSavefileManager();
 	virtual FilesystemFactory *getFilesystemFactory();
diff --git a/backends/platform/psp/osys_psp.cpp b/backends/platform/psp/osys_psp.cpp
index 8670456e55..7f38e3c4bb 100644
--- a/backends/platform/psp/osys_psp.cpp
+++ b/backends/platform/psp/osys_psp.cpp
@@ -353,16 +353,6 @@ int16 OSystem_PSP::getOverlayHeight() {
 	return _overlayHeight;
 }
 
-OverlayColor OSystem_PSP::RGBToColor(uint8 r, uint8 g, uint8 b) {
-	return (((r >> 3) & 0x1F) | (((g >> 3) & 0x1F) << 5) | (((b >> 3) & 0x1F) << 10 ) ) | 0x8000;
-}
-
-void OSystem_PSP::colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b) {
-	r = ((color & 0x1F) << 3);
-	g = (((color >> 5) & 0x1F) << 3);
-	b = (((color >> 10) & 0x1F) << 3);
-}
-
 
 void OSystem_PSP::grabPalette(byte *colors, uint start, uint num) {
 	uint i;
diff --git a/backends/platform/psp/osys_psp.h b/backends/platform/psp/osys_psp.h
index 783bb87b9c..d91526e41c 100644
--- a/backends/platform/psp/osys_psp.h
+++ b/backends/platform/psp/osys_psp.h
@@ -107,8 +107,6 @@ public:
 	virtual void copyRectToOverlay(const OverlayColor *buf, int pitch, int x, int y, int w, int h);
 	virtual int16 getOverlayHeight();
 	virtual int16 getOverlayWidth();
-	virtual OverlayColor RGBToColor(uint8 r, uint8 g, uint8 b);
-	virtual void colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b);
 	virtual void grabPalette(byte *colors, uint start, uint num);
 	virtual Graphics::PixelFormat getOverlayFormat() const { return Graphics::createPixelFormat<1555>(); }
 
diff --git a/backends/platform/sdl/graphics.cpp b/backends/platform/sdl/graphics.cpp
index 1dde92af72..c2a6285001 100644
--- a/backends/platform/sdl/graphics.cpp
+++ b/backends/platform/sdl/graphics.cpp
@@ -1239,14 +1239,6 @@ void OSystem_SDL::copyRectToOverlay(const OverlayColor *buf, int pitch, int x, i
 	SDL_UnlockSurface(_overlayscreen);
 }
 
-OverlayColor OSystem_SDL::RGBToColor(uint8 r, uint8 g, uint8 b) {
-	return SDL_MapRGB(_overlayscreen->format, r, g, b);
-}
-
-void OSystem_SDL::colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b) {
-	SDL_GetRGB(color, _overlayscreen->format, &r, &g, &b);
-}
-
 
 #pragma mark -
 #pragma mark --- Mouse ---
diff --git a/backends/platform/sdl/sdl.h b/backends/platform/sdl/sdl.h
index cb625f130c..6005b14e1c 100644
--- a/backends/platform/sdl/sdl.h
+++ b/backends/platform/sdl/sdl.h
@@ -182,11 +182,6 @@ public:
 	virtual int16 getOverlayHeight()  { return _overlayHeight; }
 	virtual int16 getOverlayWidth()   { return _overlayWidth; }
 
-	// Methods that convert RGB to/from colors suitable for the overlay.
-	virtual OverlayColor RGBToColor(uint8 r, uint8 g, uint8 b);
-	virtual void colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b);
-
-
 	virtual const GraphicsMode *getSupportedGraphicsModes() const;
 	virtual int getDefaultGraphicsMode() const;
 	virtual bool setGraphicsMode(int mode);
diff --git a/backends/platform/wii/osystem.h b/backends/platform/wii/osystem.h
index f17644ba1b..bedfadd934 100644
--- a/backends/platform/wii/osystem.h
+++ b/backends/platform/wii/osystem.h
@@ -136,9 +136,7 @@ public:
 									int x, int y, int w, int h);
 	virtual int16 getOverlayWidth();
 	virtual int16 getOverlayHeight();
-
-	virtual OverlayColor RGBToColor(uint8 r, uint8 g, uint8 b);
-	virtual void colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b);
+	virtual Graphics::PixelFormat getOverlayFormat() const { return Graphics::createPixelFormat<565>(); }
 
 	virtual bool showMouse(bool visible);
 
diff --git a/backends/platform/wii/osystem_gfx.cpp b/backends/platform/wii/osystem_gfx.cpp
index f6406a88ed..9ce70e70c3 100644
--- a/backends/platform/wii/osystem_gfx.cpp
+++ b/backends/platform/wii/osystem_gfx.cpp
@@ -197,7 +197,7 @@ int16 OSystem_Wii::getHeight() {
 void OSystem_Wii::setPalette(const byte *colors, uint start, uint num) {
 	const byte *p = colors;
 	for (uint i = 0; i < num; ++i) {
-		_palette[start + i] = RGBToColor(p[0], p[1], p[2]);
+		_palette[start + i] = Graphics::RGBToColor<ColorMasks<565> >(p[0], p[1], p[2]);
 		p += 4;
 	}
 }
@@ -206,7 +206,7 @@ void OSystem_Wii::grabPalette(byte *colors, uint start, uint num) {
 	byte *p = colors;
 	u8 r, g, b;
 	for (uint i = 0; i < num; ++i) {
-		colorToRGB(_palette[start + i], r, g, b);
+		Graphics::colorToRGB<ColorMasks<565> >(_palette[start + i], r, g, b);
 		p[0] = r;
 		p[1] = g;
 		p[2] = b;
@@ -218,7 +218,7 @@ void OSystem_Wii::grabPalette(byte *colors, uint start, uint num) {
 void OSystem_Wii::setCursorPalette(const byte *colors, uint start, uint num) {
 	const byte *p = colors;
 	for (uint i = 0; i < num; ++i) {
-		_cursorPalette[start + i] = RGBToColor(p[0], p[1], p[2]);
+		_cursorPalette[start + i] = Graphics::RGBToColor<ColorMasks<565> >(p[0], p[1], p[2]);
 		p += 4;
 	}
 
@@ -443,17 +443,6 @@ int16 OSystem_Wii::getOverlayHeight() {
 	return _overlayHeight;
 }
 
-OverlayColor OSystem_Wii::RGBToColor(uint8 r, uint8 g, uint8 b) {
-	return (((r >> 3) & 0x1f) << 11) | (((g >> 2) & 0x3f) << 5 ) |
-			((b >> 3) & 0x1f);
-}
-
-void OSystem_Wii::colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b) {
-	r = ((color >> 11) & 0x1f) << 3;
-	g = ((color >> 5) & 0x3f) << 2;
-	b = (color & 0x1f) << 3;
-}
-
 bool OSystem_Wii::showMouse(bool visible) {
 	bool last = _mouseVisible;
 	_mouseVisible = visible;
diff --git a/backends/platform/wince/wince-sdl.cpp b/backends/platform/wince/wince-sdl.cpp
index f09a483086..45935d1696 100644
--- a/backends/platform/wince/wince-sdl.cpp
+++ b/backends/platform/wince/wince-sdl.cpp
@@ -1973,7 +1973,7 @@ void OSystem_WINCE3::internDrawMouse() {
 				*bak++ = *(uint16 *)dst;
 				color = *src++;
 				if (color != 0xFF)	// 0xFF = transparent, don't draw
-					*(uint16 *)dst = RGBToColor(_currentPalette[color].r, _currentPalette[color].g, _currentPalette[color].b);
+					*(uint16 *)dst = SDL_MapRGB(_overlayscreen->format, _currentPalette[color].r, _currentPalette[color].g, _currentPalette[color].b);
 				dst += 2;
 				width--;
 			}
diff --git a/common/system.cpp b/common/system.cpp
index 1c9f0cd352..e7dee4ced6 100644
--- a/common/system.cpp
+++ b/common/system.cpp
@@ -61,14 +61,6 @@ bool OSystem::setGraphicsMode(const char *name) {
 	return false;
 }
 
-OverlayColor OSystem::RGBToColor(uint8 r, uint8 g, uint8 b) {
-	return Graphics::RGBToColor<Graphics::ColorMasks<565> >(r, g, b);
-}
-
-void OSystem::colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b) {
-	Graphics::colorToRGB<Graphics::ColorMasks<565> >(color, r, g, b);
-}
-
 void OSystem::displayMessageOnOSD(const char *msg) {
 	// Display the message for 1.5 seconds
 	GUI::TimedMessageDialog dialog(msg, 1500);
diff --git a/common/system.h b/common/system.h
index c24ca2f343..a6880e5423 100644
--- a/common/system.h
+++ b/common/system.h
@@ -617,24 +617,6 @@ public:
 	 */
 	virtual int16 getOverlayWidth()   { return getWidth(); }
 
-	/**
-	* Convert the given RGB triplet into an OverlayColor. A OverlayColor can
-	 * be 8bit, 16bit or 32bit, depending on the target system. The default
-	 * implementation generates a 16 bit color value, in the 565 format
-	 * (that is, 5 bits red, 6 bits green, 5 bits blue).
-	 * @see colorToRGB
-	 */
-	virtual OverlayColor RGBToColor(uint8 r, uint8 g, uint8 b);
-
-	/**
-	 * Convert the given OverlayColor into a RGB triplet. An OverlayColor can
-	 * be 8bit, 16bit or 32bit, depending on the target system. The default
-	 * implementation takes a 16 bit color value and assumes it to be in 565 format
-	 * (that is, 5 bits red, 6 bits green, 5 bits blue).
-	 * @see RGBToColor
-	 */
-	virtual void colorToRGB(OverlayColor color, uint8 &r, uint8 &g, uint8 &b);
-
 	//@}
 
 
diff --git a/engines/sword1/animation.cpp b/engines/sword1/animation.cpp
index a033abbc3d..c0cd85a7c2 100644
--- a/engines/sword1/animation.cpp
+++ b/engines/sword1/animation.cpp
@@ -555,9 +555,10 @@ bool MoviePlayerMPEG::initOverlays(uint32 id) {
 						_logoOvls[fcnt][cnt] = _logoOvls[fcnt - 1][cnt];
 		}
 		uint8 *pal = ovlFile.fetchFile(12);
-		_introPal = (OverlayColor*)malloc(256 * sizeof(OverlayColor));
+		_introPal = (OverlayColor *)malloc(256 * sizeof(OverlayColor));
+		Graphics::PixelFormat format = _system->getOverlayFormat();
 		for (uint16 cnt = 0; cnt < 256; cnt++)
-			_introPal[cnt] = _system->RGBToColor(pal[cnt * 3 + 0], pal[cnt * 3 + 1], pal[cnt * 3 + 2]);
+			_introPal[cnt] = Graphics::RGBToColor(pal[cnt * 3 + 0], pal[cnt * 3 + 1], pal[cnt * 3 + 2], format);
 	}
 
 	return true;
diff --git a/engines/sword2/animation.cpp b/engines/sword2/animation.cpp
index fb5642a816..1452cc61dc 100644
--- a/engines/sword2/animation.cpp
+++ b/engines/sword2/animation.cpp
@@ -654,8 +654,9 @@ void AnimationState::drawTextObject(SpriteInfo *s, byte *src) {
 
 	OverlayColor *dst = _overlay + textY * moviePitch + textX;
 
-	OverlayColor pen = _sys->RGBToColor(255, 255, 255);
-	OverlayColor border = _sys->RGBToColor(0, 0, 0);
+	Graphics::PixelFormat format = _sys->getOverlayFormat();
+	OverlayColor pen = Graphics::RGBToColor(255, 255, 255, format);
+	OverlayColor border = Graphics::RGBToColor(0, 0, 0, format);
 
 	// TODO: Use the AdvMame scalers for the text? Pre-scale it?
 
@@ -702,7 +703,8 @@ void AnimationState::clearFrame() {
 #ifdef BACKEND_8BIT
 	memset(_vm->_screen->getScreen(), 0, _movieWidth * _movieHeight);
 #else
-	OverlayColor black = _sys->RGBToColor(0, 0, 0);
+	Graphics::PixelFormat format = _sys->getOverlayFormat();
+	OverlayColor black = Graphics::RGBToColor(0, 0, 0, format);
 
 	for (int i = 0; i < _movieScale * _movieWidth * _movieScale * _movieHeight; i++)
 		_overlay[i] = black;
diff --git a/graphics/mpeg_player.cpp b/graphics/mpeg_player.cpp
index 3c0fd08cb3..7432887360 100644
--- a/graphics/mpeg_player.cpp
+++ b/graphics/mpeg_player.cpp
@@ -389,10 +389,11 @@ void BaseAnimationState::buildLookup() {
 	}
 
 	// Set up entries 0-255 in rgb-to-pixel value tables.
+	Graphics::PixelFormat format = _sys->getOverlayFormat();
 	for (i = 0; i < 256; i++) {
-		r_2_pix_alloc[i + 256] = _sys->RGBToColor(i, 0, 0);
-		g_2_pix_alloc[i + 256] = _sys->RGBToColor(0, i, 0);
-		b_2_pix_alloc[i + 256] = _sys->RGBToColor(0, 0, i);
+		r_2_pix_alloc[i + 256] = Graphics::RGBToColor(i, 0, 0, format);
+		g_2_pix_alloc[i + 256] = Graphics::RGBToColor(0, i, 0, format);
+		b_2_pix_alloc[i + 256] = Graphics::RGBToColor(0, 0, i, format);
 	}
 
 	// Spread out the values we have to the rest of the array so that we do
diff --git a/graphics/thumbnail.cpp b/graphics/thumbnail.cpp
index 905fea3d93..709ba9ea54 100644
--- a/graphics/thumbnail.cpp
+++ b/graphics/thumbnail.cpp
@@ -42,12 +42,6 @@ struct ThumbnailHeader {
 
 #define ThumbnailHeaderSize (4+4+1+2+2+1)
 
-inline void colorToRGB(uint16 color, uint8 &r, uint8 &g, uint8 &b) {
-	r = (((color >> 11) & 0x1F) << 3);
-	g = (((color >> 5) & 0x3F) << 2);
-	b = ((color&0x1F) << 3);
-}
-
 bool loadHeader(Common::SeekableReadStream &in, ThumbnailHeader &header, bool outputWarnings) {
 	header.type = in.readUint32BE();
 	// We also accept the bad 'BMHT' header here, for the sake of compatibility
@@ -114,13 +108,14 @@ bool loadThumbnail(Common::SeekableReadStream &in, Graphics::Surface &to) {
 	to.create(header.width, header.height, sizeof(OverlayColor));
 
 	OverlayColor *pixels = (OverlayColor *)to.pixels;
+	Graphics::PixelFormat format = g_system->getOverlayFormat();
 	for (int y = 0; y < to.h; ++y) {
 		for (int x = 0; x < to.w; ++x) {
 			uint8 r, g, b;
-			colorToRGB(in.readUint16BE(), r, g, b);
+			colorToRGB<ColorMasks<565> >(in.readUint16BE(), r, g, b);
 
 			// converting to current OSystem Color
-			*pixels++ = g_system->RGBToColor(r, g, b);
+			*pixels++ = Graphics::RGBToColor(r, g, b, format);
 		}
 	}
 
diff --git a/gui/ThemeEngine.cpp b/gui/ThemeEngine.cpp
index cbcd32fd4c..20638b827d 100644
--- a/gui/ThemeEngine.cpp
+++ b/gui/ThemeEngine.cpp
@@ -290,7 +290,7 @@ void ThemeEngine::clearAll() {
 		return;
 
 	_system->clearOverlay();
-	_system->grabOverlay((OverlayColor*)_screen->pixels, _screen->w);
+	_system->grabOverlay((OverlayColor *)_screen->pixels, _screen->w);
 }
 
 void ThemeEngine::refresh() {
@@ -941,7 +941,8 @@ void ThemeEngine::drawChar(const Common::Rect &r, byte ch, const Graphics::Font
 	Common::Rect charArea = r;
 	charArea.clip(_screen->w, _screen->h);
 
-	uint32 color = _system->RGBToColor(_texts[kTextDataDefault]->_color.r, _texts[kTextDataDefault]->_color.g, _texts[kTextDataDefault]->_color.b);
+	Graphics::PixelFormat format = _system->getOverlayFormat();
+	uint32 color = Graphics::RGBToColor(_texts[kTextDataDefault]->_color.r, _texts[kTextDataDefault]->_color.g, _texts[kTextDataDefault]->_color.b, format);
 
 	restoreBackground(charArea);
 	font->drawChar(_screen, ch, charArea.left, charArea.top, color);
@@ -1053,10 +1054,11 @@ bool ThemeEngine::createCursor(const Common::String &filename, int hotspotX, int
 	uint colorsFound = 0;
 	Common::HashMap<int, int>	colorToIndex;
 	const OverlayColor *src = (const OverlayColor*)cursor->pixels;
+	Graphics::PixelFormat format = _system->getOverlayFormat();
 	for (uint y = 0; y < _cursorHeight; ++y) {
 		for (uint x = 0; x < _cursorWidth; ++x) {
 			byte r, g, b;
-			_system->colorToRGB(src[x], r, g, b);
+			Graphics::colorToRGB(src[x], r, g, b, format);
 			const int col = (r << 16) | (g << 8) | b;
 
 			// Skip transparency (the transparent color actually is 0xFF00FF,