From 985c02ee7da43fb66b61d6e3c5530e78bd2d8286 Mon Sep 17 00:00:00 2001
From: Johannes Schickel
Date: Mon, 3 Nov 2008 13:44:59 +0000
Subject: Committed my patch #2216641 "GRAPHICS: PixelFormat introduction".

svn-id: r34875
---
 graphics/colormasks.h | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)

(limited to 'graphics/colormasks.h')

diff --git a/graphics/colormasks.h b/graphics/colormasks.h
index 5b9f0517a9..e8048f6d64 100644
--- a/graphics/colormasks.h
+++ b/graphics/colormasks.h
@@ -26,6 +26,8 @@
 #ifndef GRAPHICS_COLORMASKS_H
 #define GRAPHICS_COLORMASKS_H
 
+namespace Graphics {
+
 template<int bitFormat>
 struct ColorMasks {
 };
@@ -251,4 +253,76 @@ void colorToARGB(uint32 color, uint8 &a, uint8 &r, uint8 &g, uint8 &b) {
 	b = ((color & T::kBlueMask) >> T::kBlueShift) << (8 - T::kBlueBits);
 }
 
+/**
+ * A pixel format description.
+ *
+ * Like ColorMasks it includes the given values to create colors from RGB
+ * values and to retrieve RGB values from colors.
+ *
+ * Unlike ColorMasks it is not dependend on knowing the exact pixel format
+ * on compile time.
+ *
+ * A minor difference between ColorMasks and PixelFormat is that ColorMasks
+ * stores the bit count per channel in 'kFooBits', while PixelFormat stores
+ * the loss compared to 8 bits per channel in '#Loss'.
+ */
+struct PixelFormat {
+	byte bytesPerPixel; /**< Number of bytes used in the pixel format. */
+
+	byte rLoss, gLoss, bLoss, aLoss; /**< Precision loss of each color component. */
+	byte rShift, gShift, bShift, aShift; /**< Binary left shift of each color component in the pixel value. */
+
+	uint32 rMask, gMask, bMask, aMask; /**< Binary mask used to retrieve individual color values. */
+};
+
+template<class Mask>
+PixelFormat createPixelFormatFromMask() {
+	PixelFormat format;
+
+	format.bytesPerPixel = Mask::kBytesPerPixel;
+
+	format.rLoss = 8 - Mask::kRedBits;
+	format.gLoss = 8 - Mask::kGreenBits;
+	format.bLoss = 8 - Mask::kBlueBits;
+	format.aLoss = 8 - Mask::kAlphaBits;
+
+	format.rShift = Mask::kRedShift;
+	format.gShift = Mask::kGreenShift;
+	format.bShift = Mask::kBlueShift;
+	format.aShift = Mask::kAlphaShift;
+
+	return format;
+}
+
+inline uint32 RGBToColor(uint8 r, uint8 g, uint8 b, const PixelFormat &fmt) {
+	return
+		((0xFF >> fmt.aLoss) << fmt.aShift) |
+		((   r >> fmt.rLoss) << fmt.rShift) |
+		((   g >> fmt.gLoss) << fmt.gShift) |
+		((   b >> fmt.bLoss) << fmt.bShift);
+}
+
+inline uint32 ARGBToColor(uint8 a, uint8 r, uint8 g, uint8 b, const PixelFormat &fmt) {
+	return
+		((a >> fmt.aLoss) << fmt.aShift) |
+		((r >> fmt.rLoss) << fmt.rShift) |
+		((g >> fmt.gLoss) << fmt.gShift) |
+		((b >> fmt.bLoss) << fmt.bShift);
+}
+
+inline void colorToRGB(uint32 color, uint8 &r, uint8 &g, uint8 &b, const PixelFormat &fmt) {
+	r = ((color >> fmt.rShift) << fmt.rLoss) & 0xFF;
+	g = ((color >> fmt.gShift) << fmt.gLoss) & 0xFF;
+	b = ((color >> fmt.bShift) << fmt.bLoss) & 0xFF;
+}
+
+inline void colorToARGB(uint32 color, uint8 &a, uint8 &r, uint8 &g, uint8 &b, const PixelFormat &fmt) {
+	a = ((color >> fmt.aShift) << fmt.aLoss) & 0xFF;
+	r = ((color >> fmt.rShift) << fmt.rLoss) & 0xFF;
+	g = ((color >> fmt.gShift) << fmt.gLoss) & 0xFF;
+	b = ((color >> fmt.bShift) << fmt.bLoss) & 0xFF;
+}
+
+} // end of namespace Graphics
+
 #endif
-- 
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