Moved Graphics::PixelFormat into its own header file; turned RGBToColor etc. into methods, and added an operator==

svn-id: r35993

1 files changed, 89 insertions, 0 deletions

diff --git a/graphics/pixelformat.h b/graphics/pixelformat.h
new file mode 100644
index 0000000000..bfec28fabd
--- /dev/null
+++ b/graphics/pixelformat.h
@@ -0,0 +1,89 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * $URL$
+ * $Id$
+ *
+ */
+
+#ifndef GRAPHICS_PIXELFORMAT_H
+#define GRAPHICS_PIXELFORMAT_H
+
+namespace Graphics {
+
+
+/**
+ * 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'. It also doesn't
+ * contain mask values.
+ */
+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. */
+
+	inline bool operator==(const PixelFormat &fmt) const {
+		// TODO: If aLoss==8, then the value of aShift is irrelevant, and should be ignored.
+		return 0 == memcmp(this, &fmt, sizeof(PixelFormat));
+	}
+
+	inline uint32 RGBToColor(uint8 r, uint8 g, uint8 b) const {
+		return
+			((0xFF >> aLoss) << aShift) |
+			((   r >> rLoss) << rShift) |
+			((   g >> gLoss) << gShift) |
+			((   b >> bLoss) << bShift);
+	}
+
+	inline uint32 ARGBToColor(uint8 a, uint8 r, uint8 g, uint8 b) const {
+		return
+			((a >> aLoss) << aShift) |
+			((r >> rLoss) << rShift) |
+			((g >> gLoss) << gShift) |
+			((b >> bLoss) << bShift);
+	}
+
+	inline void colorToRGB(uint32 color, uint8 &r, uint8 &g, uint8 &b) const {
+		r = ((color >> rShift) << rLoss) & 0xFF;
+		g = ((color >> gShift) << gLoss) & 0xFF;
+		b = ((color >> bShift) << bLoss) & 0xFF;
+	}
+
+	inline void colorToARGB(uint32 color, uint8 &a, uint8 &r, uint8 &g, uint8 &b) const {
+		a = ((color >> aShift) << aLoss) & 0xFF;
+		r = ((color >> rShift) << rLoss) & 0xFF;
+		g = ((color >> gShift) << gLoss) & 0xFF;
+		b = ((color >> bShift) << bLoss) & 0xFF;
+	}
+};
+
+} // end of namespace Graphics
+
+#endif