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/* 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.
*
*/
#ifndef GRAPHICS_PIXELFORMAT_H
#define GRAPHICS_PIXELFORMAT_H
#include "common/scummsys.h"
namespace Graphics {
/** Template to expand from an n-bit component to an 8-bit component */
template<int depth>
struct ColorComponent {
};
template<>
struct ColorComponent<0> {
static inline uint expand(uint value) {
return 0;
}
};
template<>
struct ColorComponent<1> {
static inline uint expand(uint value) {
value &= 1;
return value |
(value << 1) |
(value << 2) |
(value << 3) |
(value << 4) |
(value << 5) |
(value << 6) |
(value << 7);
}
};
template<>
struct ColorComponent<2> {
static inline uint expand(uint value) {
value &= 3;
return value |
(value << 2) |
(value << 4) |
(value << 6);
}
};
template<>
struct ColorComponent<3> {
static inline uint expand(uint value) {
value &= 7;
return (value << 5) |
(value << 2) |
(value >> 1);
}
};
template<>
struct ColorComponent<4> {
static inline uint expand(uint value) {
value &= 15;
return value |
(value << 4);
}
};
template<>
struct ColorComponent<5> {
static inline uint expand(uint value) {
value &= 31;
return (value << 3) |
(value >> 2);
}
};
template<>
struct ColorComponent<6> {
static inline uint expand(uint value) {
value &= 63;
return (value << 2) |
(value >> 4);
}
};
template<>
struct ColorComponent<7> {
static inline uint expand(uint value) {
value &= 127;
return (value << 1) |
(value >> 6);
}
};
template<>
struct ColorComponent<8> {
static inline uint expand(uint value) {
return value & 255;
}
};
/**
* 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 PixelFormat() {
bytesPerPixel =
rLoss = gLoss = bLoss = aLoss =
rShift = gShift = bShift = aShift = 0;
}
inline PixelFormat(byte BytesPerPixel,
byte RBits, byte GBits, byte BBits, byte ABits,
byte RShift, byte GShift, byte BShift, byte AShift) {
bytesPerPixel = BytesPerPixel;
rLoss = 8 - RBits, gLoss = 8 - GBits, bLoss = 8 - BBits, aLoss = 8 - ABits;
rShift = RShift, gShift = GShift, bShift = BShift, aShift = AShift;
}
static inline PixelFormat createFormatCLUT8() {
return PixelFormat(1, 0, 0, 0, 0, 0, 0, 0, 0);
}
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 bool operator!=(const PixelFormat &fmt) const {
return !(*this == fmt);
}
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 = expand(rBits(), color >> rShift);
g = expand(gBits(), color >> gShift);
b = expand(bBits(), color >> bShift);
}
inline void colorToARGB(uint32 color, uint8 &a, uint8 &r, uint8 &g, uint8 &b) const {
a = (aBits() == 0) ? 0xFF : expand(aBits(), color >> aShift);
r = expand(rBits(), color >> rShift);
g = expand(gBits(), color >> gShift);
b = expand(bBits(), color >> bShift);
}
//////////////////////////////////////////////////////////////////////
// Convenience functions for getting number of color component bits //
//////////////////////////////////////////////////////////////////////
inline byte rBits() const {
return (8 - rLoss);
}
inline byte gBits() const {
return (8 - gLoss);
}
inline byte bBits() const {
return (8 - bLoss);
}
inline byte aBits() const {
return (8 - aLoss);
}
////////////////////////////////////////////////////////////////////////
// Convenience functions for getting color components' maximum values //
////////////////////////////////////////////////////////////////////////
inline uint rMax() const {
return (1 << rBits()) - 1;
}
inline uint gMax() const {
return (1 << gBits()) - 1;
}
inline uint bMax() const {
return (1 << bBits()) - 1;
}
inline uint aMax() const {
return (1 << aBits()) - 1;
}
/** Expand a given bit-depth component to a full 8-bit component */
static inline uint expand(uint bits, uint color) {
switch (bits) {
case 0:
return ColorComponent<0>::expand(color);
case 1:
return ColorComponent<1>::expand(color);
case 2:
return ColorComponent<2>::expand(color);
case 3:
return ColorComponent<3>::expand(color);
case 4:
return ColorComponent<4>::expand(color);
case 5:
return ColorComponent<5>::expand(color);
case 6:
return ColorComponent<6>::expand(color);
case 7:
return ColorComponent<7>::expand(color);
case 8:
return ColorComponent<8>::expand(color);
}
// Unsupported
return 0;
}
};
} // End of namespace Graphics
#endif
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