Laying the foundation for preliminary bitdepth negotiation. (No functionality changes yet)

svn-id: r41396

3 files changed, 83 insertions, 1 deletions

diff --git a/backends/platform/sdl/sdl.h b/backends/platform/sdl/sdl.h
index 6fe871fa83..22d3d41b00 100644
--- a/backends/platform/sdl/sdl.h
+++ b/backends/platform/sdl/sdl.h
@@ -178,6 +178,12 @@ public:
 
 	// Overlay
 	virtual Graphics::PixelFormat getOverlayFormat() const { return _overlayFormat; }
+
+#ifdef ENABLE_16BIT
+	// Game screen
+	virtual Graphics::PixelFormat getScreenFormat() const { return _screenFormat; }
+#endif
+
 	virtual void showOverlay();
 	virtual void hideOverlay();
 	virtual void clearOverlay();
@@ -232,7 +238,12 @@ protected:
 	// unseen game screen
 	SDL_Surface *_screen;
 #ifdef ENABLE_16BIT
-	SDL_Surface *_screen16;
+	Graphics::PixelFormat _screenFormat;
+
+	//HACK This is a temporary hack to get 16-bit graphics
+	//displaying quickly, which will be removed in favor of 
+	//configuring the format of _screen on a per-game basis
+	SDL_Surface *_screen16;	
 #endif
 
 	// temporary screen (for scalers)
diff --git a/common/system.h b/common/system.h
index ddbcdcc546..50d00bb8e2 100644
--- a/common/system.h
+++ b/common/system.h
@@ -407,6 +407,9 @@ public:
 		kTransactionAspectRatioFailed = (1 << 0),	/**< Failed switchting aspect ratio correction mode */
 		kTransactionFullscreenFailed = (1 << 1),	/**< Failed switchting fullscreen mode */
 		kTransactionModeSwitchFailed = (1 << 2),	/**< Failed switchting the GFX graphics mode (setGraphicsMode) */
+#ifdef ENABLE_16BIT
+		kTransactionPixelFormatNotSupported = (1 << 4), /**< Failed setting the color format (function not yet implemented) */
+#endif
 		kTransactionSizeChangeFailed = (1 << 3)		/**< Failed switchting the screen dimensions (initSize) */
 	};
 
@@ -605,6 +608,14 @@ public:
 	 */
 	virtual Graphics::PixelFormat getOverlayFormat() const = 0;
 
+#ifdef ENABLE_16BIT
+	/**
+	 * Returns the pixel format description of the game screen.
+	 * @see Graphics::PixelFormat
+	 */
+	virtual Graphics::PixelFormat getScreenFormat() const = 0;
+#endif
+
 	/**
 	 * Reset the overlay.
 	 *
diff --git a/graphics/pixelformat.h b/graphics/pixelformat.h
index f59650e5cc..2e8c065414 100644
--- a/graphics/pixelformat.h
+++ b/graphics/pixelformat.h
@@ -30,6 +30,66 @@
 
 namespace Graphics {
 
+#ifdef ENABLE_16BIT
+/**
+ * A condensed bit format description.
+ *
+ * It includes the necessary information to create a PixelFormat and/or 
+ * ColorMask which fully describe the given color format.
+ *
+ * It contains two components, the format (8Bit paletted, RGB555, etc)
+ * and the order (palette, ARGB, ABGR, etc)
+ *
+ * Use (format & kFormatTypeMask) to get the type, and (format & kFormatOrderMask)
+ * to get the applicable color order.
+  */
+enum ColorFormat {
+	kFormat8Bit = 0,
+	kFormatRGB555 = 1,
+	kFormatARGB1555 = 2,	// Rare, but I know a guy who knows a guy who's heard of it being used
+	kFormatRGB556 = 3,		// 6 bits for blue, in case this ever happens
+	kFormatRGB565 = 4,
+	kFormatRGB655 = 5,		// 6 bits for red, in case this ever happens
+	kFormatARGB4444 = 6,
+	kFormatRGB888 = 7,
+	kFormatARGB6666 = 8,	// I've never heard of this, but it's theoretically possible
+	kFormatARGB8888 = 9,
+	kFormatTypeMask = 0xFF, // & by this to get the overall bit format
+	kFormatPalette = 0 << 8,
+	kFormatRGB = 1 << 8,
+	kFormatRBG = 2 << 8,
+	kFormatGRB = 3 << 8,
+	kFormatGBR = 4 << 8,
+	kFormatBRG = 5 << 8,
+	kFormatBGR = 6 << 8,
+	kFormatARGB = 7 << 8,
+	kFormatARBG = 8 << 8,
+	kFormatAGRB = 9 << 8,
+	kFormatAGBR = 10 << 8,
+	kFormatABRG = 11 << 8,
+	kFormatABGR = 12 << 8,
+	kFormatRAGB = 13 << 8,
+	kFormatRABG = 14 << 8,
+	kFormatGARB = 15 << 8,
+	kFormatGABR = 16 << 8,
+	kFormatBARG = 17 << 8,
+	kFormatBAGR = 18 << 8,
+	kFormatRGAB = 19 << 8,
+	kFormatRBAG = 20 << 8,
+	kFormatGRAB = 21 << 8,
+	kFormatGBAR = 22 << 8,
+	kFormatBRAG = 23 << 8,
+	kFormatBGAR = 24 << 8,
+	kFormatRGBA = 25 << 8,
+	kFormatRBGA = 26 << 8,
+	kFormatGRBA = 27 << 8,
+	kFormatGBRA = 28 << 8,
+	kFormatBRGA = 29 << 8,
+	kFormatBGRA = 30 << 8,
+	kFormatOrderMask = 0xFF << 8 // & by this to get the order
+};
+#endif
+
 /**
  * A pixel format description.
  *