Moved ColorMasks to their own new header graphics/colormasks.h, so that both the scalers and the GUI code can access them. Also added (untested) entries for 1555, 444, 888 and 8888 modes

svn-id: r21966

1 files changed, 221 insertions, 0 deletions

diff --git a/graphics/colormasks.h b/graphics/colormasks.h
new file mode 100644
index 0000000000..422af23d85
--- /dev/null
+++ b/graphics/colormasks.h
@@ -0,0 +1,221 @@
+/* ScummVM - Scumm Interpreter
+ * Copyright (C) 2001  Ludvig Strigeus
+ * Copyright (C) 2001-2006 The ScummVM project
+ *
+ * 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_COLORMASKS_H
+#define GRAPHICS_COLORMASKS_H
+
+template<int bitFormat>
+struct ColorMasks {
+};
+
+/*
+The ColorMasks template can be used to map bit format values
+(like 555, 565, 1555, 4444) to corresponding bit masks and shift values.
+Currently this is only meant for 
+
+The meaning of these is masks is the following:
+ kBytesPerPixel
+    -> how many bytes per pixel for that format
+
+ kRedMask, kGreenMask, kBlueMask
+    -> bitmask, and this with the color to select only the bits of the corresponding color
+ 
+ The k*Bits and k*Shift values can be used to extract R,G,B. I.e. to get
+ the red color component of a pixel, as a 8-bit value, you would write
+ 
+ R = ((color & kRedMask) >> kRedShift) << (8-kRedBits)
+ 
+ Actually, instead of the simple left shift, one might want to use somewhat
+ more sophisticated code (which fills up the lower most bits.
+ 
+ 
+ The highBits / lowBits / qhighBits / qlowBits are special values that are
+ used in the super-optimized interpolation functions in scaler/intern.h
+ and scaler/aspect.cpp. Currently they are only available in 555 and 565 mode.
+ To be specific: They pack the masks for two 16 bit pixels at once. The pixels
+ are split into "high" and "low" bits, which are then separately interpolated
+ and finally re-composed. That way, 2x2 pixels or even 4x2 pixels can
+ be interpolated in one go.
+
+*/
+
+
+template<>
+struct ColorMasks<565> {
+	enum {
+		highBits    = 0xF7DEF7DE,
+		lowBits     = 0x08210821,
+		qhighBits   = 0xE79CE79C,
+		qlowBits    = 0x18631863,
+
+
+		kBytesPerPixel = 2,
+
+		kAlphaBits  = 0,
+		kRedBits    = 5,
+		kGreenBits  = 6,
+		kBlueBits   = 5,
+
+		kAlphaShift = kRedBits+kGreenBits+kBlueBits,
+		kRedShift   = kGreenBits+kBlueBits,
+		kGreenShift = kBlueBits,
+		kBlueShift  = 0,
+
+		kAlphaMask = ((1 << kAlphaBits) - 1) << kAlphaShift,
+		kRedMask   = ((1 << kRedBits) - 1) << kRedShift,
+		kGreenMask = ((1 << kGreenBits) - 1) << kGreenShift,
+		kBlueMask  = ((1 << kBlueBits) - 1) << kBlueShift,
+
+		kRedBlueMask = kRedMask | kBlueMask
+
+	};
+};
+
+template<>
+struct ColorMasks<555> {
+	enum {
+		highBits    = 0x7BDE7BDE,
+		lowBits     = 0x04210421,
+		qhighBits   = 0x739C739C,
+		qlowBits    = 0x0C630C63,
+
+
+		kBytesPerPixel = 2,
+
+		kAlphaBits  = 0,
+		kRedBits    = 5,
+		kGreenBits  = 5,
+		kBlueBits   = 5,
+
+		kAlphaShift = kRedBits+kGreenBits+kBlueBits,
+		kRedShift   = kGreenBits+kBlueBits,
+		kGreenShift = kBlueBits,
+		kBlueShift  = 0,
+
+		kAlphaMask = ((1 << kAlphaBits) - 1) << kAlphaShift,
+		kRedMask   = ((1 << kRedBits) - 1) << kRedShift,
+		kGreenMask = ((1 << kGreenBits) - 1) << kGreenShift,
+		kBlueMask  = ((1 << kBlueBits) - 1) << kBlueShift,
+
+		kRedBlueMask = kRedMask | kBlueMask
+	};
+};
+
+template<>
+struct ColorMasks<1555> {
+	enum {
+		kBytesPerPixel = 2,
+
+		kAlphaBits  = 1,
+		kRedBits    = 5,
+		kGreenBits  = 5,
+		kBlueBits   = 5,
+
+		kAlphaShift = kRedBits+kGreenBits+kBlueBits,
+		kRedShift   = kGreenBits+kBlueBits,
+		kGreenShift = kBlueBits,
+		kBlueShift  = 0,
+
+		kAlphaMask = ((1 << kAlphaBits) - 1) << kAlphaShift,
+		kRedMask   = ((1 << kRedBits) - 1) << kRedShift,
+		kGreenMask = ((1 << kGreenBits) - 1) << kGreenShift,
+		kBlueMask  = ((1 << kBlueBits) - 1) << kBlueShift,
+
+		kRedBlueMask = kRedMask | kBlueMask
+	};
+};
+
+template<>
+struct ColorMasks<4444> {
+	enum {
+		kBytesPerPixel = 2,
+
+		kAlphaBits  = 4,
+		kRedBits    = 4,
+		kGreenBits  = 4,
+		kBlueBits   = 4,
+
+		kAlphaShift = kRedBits+kGreenBits+kBlueBits,
+		kRedShift   = kGreenBits+kBlueBits,
+		kGreenShift = kBlueBits,
+		kBlueShift  = 0,
+
+		kAlphaMask = ((1 << kAlphaBits) - 1) << kAlphaShift,
+		kRedMask   = ((1 << kRedBits) - 1) << kRedShift,
+		kGreenMask = ((1 << kGreenBits) - 1) << kGreenShift,
+		kBlueMask  = ((1 << kBlueBits) - 1) << kBlueShift,
+
+		kRedBlueMask = kRedMask | kBlueMask
+	};
+};
+
+template<>
+struct ColorMasks<888> {
+	enum {
+		kBytesPerPixel = 4,
+
+		kAlphaBits  = 0,
+		kRedBits    = 8,
+		kGreenBits  = 8,
+		kBlueBits   = 8,
+
+		kAlphaShift = kRedBits+kGreenBits+kBlueBits,
+		kRedShift   = kGreenBits+kBlueBits,
+		kGreenShift = kBlueBits,
+		kBlueShift  = 0,
+
+		kAlphaMask = ((1 << kAlphaBits) - 1) << kAlphaShift,
+		kRedMask   = ((1 << kRedBits) - 1) << kRedShift,
+		kGreenMask = ((1 << kGreenBits) - 1) << kGreenShift,
+		kBlueMask  = ((1 << kBlueBits) - 1) << kBlueShift,
+
+		kRedBlueMask = kRedMask | kBlueMask
+	};
+};
+
+template<>
+struct ColorMasks<8888> {
+	enum {
+		kBytesPerPixel = 4,
+
+		kAlphaBits  = 8,
+		kRedBits    = 8,
+		kGreenBits  = 8,
+		kBlueBits   = 8,
+
+		kAlphaShift = kRedBits+kGreenBits+kBlueBits,
+		kRedShift   = kGreenBits+kBlueBits,
+		kGreenShift = kBlueBits,
+		kBlueShift  = 0,
+
+		kAlphaMask = ((1 << kAlphaBits) - 1) << kAlphaShift,
+		kRedMask   = ((1 << kRedBits) - 1) << kRedShift,
+		kGreenMask = ((1 << kGreenBits) - 1) << kGreenShift,
+		kBlueMask  = ((1 << kBlueBits) - 1) << kBlueShift,
+
+		kRedBlueMask = kRedMask | kBlueMask
+	};
+};
+
+
+#endif