/* 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"
#include "common/str.h"
#include "graphics/colormasks.h"
namespace Graphics {
/**
* @defgroup graphics_pixelformat Pixel formats
* @ingroup graphics
*
* @brief Structures for managing pixel formats.
*
* @{
*/
/** Template to expand from an n-bit component to an 8-bit component. */
template<int depth>
struct ColorComponent {
};
/** Return 0 for an empty color component. */
template<>
struct ColorComponent<0> {
static inline uint expand(uint value) {
return 0;
}
};
/** Template to expand a 1-bit component into an 8-bit component. */
template<>
struct ColorComponent<1> {
static inline uint expand(uint value) {
return value ? 0xff : 0;
}
};
/** Template to expand a 2-bit component into an 8-bit component. */
template<>
struct ColorComponent<2> {
static inline uint expand(uint value) {
value &= 3;
return value |
(value << 2) |
(value << 4) |
(value << 6);
}
};
/** Template to expand a 3-bit component into an 8-bit component. */
template<>
struct ColorComponent<3> {
static inline uint expand(uint value) {
value &= 7;
return (value << 5) |
(value << 2) |
(value >> 1);
}
};
/** Template to expand a 4-bit component into an 8-bit component. */
template<>
struct ColorComponent<4> {
static inline uint expand(uint value) {
value &= 15;
return value |
(value << 4);
}
};
/** Template to expand a 5-bit component into an 8-bit component. */
template<>
struct ColorComponent<5> {
static inline uint expand(uint value) {
value &= 31;
return (value << 3) |
(value >> 2);
}
};
/** Template to expand a 6-bit component into an 8-bit component. */
template<>
struct ColorComponent<6> {
static inline uint expand(uint value) {
value &= 63;
return (value << 2) |
(value >> 4);
}
};
/** Template to expand a 7-bit component into an 8-bit component. */
template<>
struct ColorComponent<7> {
static inline uint expand(uint value) {
value &= 127;
return (value << 1) |
(value >> 6);
}
};
/** Return the given value. */
template<>
struct ColorComponent<8> {
static inline uint expand(uint value) {
return value & 255;
}
};
/**
* 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 dependent 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 @c kFooBits, while PixelFormat stores
* the loss compared to 8 bits per channel in @c \#Loss. It also does not
* 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. */
/** Default constructor that creates a null pixel format. */
inline PixelFormat() {
bytesPerPixel =
rLoss = gLoss = bLoss = aLoss =
rShift = gShift = bShift = aShift = 0;
}
/** Construct a pixel format based on the provided arguments.
*
* Examples:
*
* - RGBA8888:
* @code
* BytesPerPixel = 4, RBits = GBits = BBits = ABits = 8, RShift = 24, GShift = 16, BShift = 8, AShift = 0
* @endcode
* - ABGR8888:
* @code
* BytesPerPixel = 4, RBits = GBits = BBits = ABits = 8, RShift = 0, GShift = 8, BShift = 16, AShift = 24
* @endcode
* - RGB565:
* @code
* BytesPerPixel = 2, RBits = 5, GBits = 6, BBits = 5, ABits = 0, RShift = 11, GShift = 5, BShift = 0, AShift = 0
* @endcode
*/
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;
}
/** Define a CLUT8 pixel format. */
static inline PixelFormat createFormatCLUT8() {
return PixelFormat(1, 0, 0, 0, 0, 0, 0, 0, 0);
}
/** Check if two pixel formats are the same */
inline bool operator==(const PixelFormat &fmt) const {
// TODO: If aLoss==8, then the value of aShift is irrelevant, and should be ignored.
return bytesPerPixel == fmt.bytesPerPixel &&
rLoss == fmt.rLoss &&
gLoss == fmt.gLoss &&
bLoss == fmt.bLoss &&
aLoss == fmt.aLoss &&
rShift == fmt.rShift &&
gShift == fmt.gShift &&
bShift == fmt.bShift &&
aShift == fmt.aShift;
}
/** Check if two pixel formats are different. */
inline bool operator!=(const PixelFormat &fmt) const {
return !(*this == fmt);
}
/** Return an RGB color value from red, green, and blue values. */
inline uint32 RGBToColor(uint8 r, uint8 g, uint8 b) const {
return
((0xFF >> aLoss) << aShift) |
(( r >> rLoss) << rShift) |
(( g >> gLoss) << gShift) |
(( b >> bLoss) << bShift);
}
template<class T>
inline uint32 RGBToColorT(uint8 r, uint8 g, uint8 b) const {
return T::kAlphaMask |
(((r << T::kRedShift) >> (8 - T::kRedBits)) & T::kRedMask) |
(((g << T::kGreenShift) >> (8 - T::kGreenBits)) & T::kGreenMask) |
(((b << T::kBlueShift) >> (8 - T::kBlueBits)) & T::kBlueMask);
}
/** Return an ARGB color value from alpha, red, green, and blue values. */
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);
}
template<class T>
inline uint32 ARGBToColorT(uint8 a, uint8 r, uint8 g, uint8 b) const {
return (((a << T::kAlphaShift) >> (8 - T::kAlphaBits)) & T::kAlphaMask) |
(((r << T::kRedShift) >> (8 - T::kRedBits)) & T::kRedMask) |
(((g << T::kGreenShift) >> (8 - T::kGreenBits)) & T::kGreenMask) |
(((b << T::kBlueShift) >> (8 - T::kBlueBits)) & T::kBlueMask);
}
/** Retrieve red, green, and blue values from an RGB color value. */
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);
}
template<class T>
inline void colorToRGBT(uint32 color, uint8 &r, uint8 &g, uint8 &b) const {
r = ((color & T::kRedMask) >> T::kRedShift) << (8 - T::kRedBits);
g = ((color & T::kGreenMask) >> T::kGreenShift) << (8 - T::kGreenBits);
b = ((color & T::kBlueMask) >> T::kBlueShift) << (8 - T::kBlueBits);
}
/** Retrieve alpha, red, green, and blue values from an ARGB color value. */
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);
}
template<class T>
inline void colorToARGBT(uint32 color, uint8 &a, uint8 &r, uint8 &g, uint8 &b) const {
a = ((color & T::kAlphaMask) >> T::kAlphaShift) << (8 - T::kAlphaBits);
r = ((color & T::kRedMask) >> T::kRedShift) << (8 - T::kRedBits);
g = ((color & T::kGreenMask) >> T::kGreenShift) << (8 - T::kGreenBits);
b = ((color & T::kBlueMask) >> T::kBlueShift) << (8 - T::kBlueBits);
}
/**
* @name Convenience functions for getting the number of color component bits
* @{
*/
/**
* Return the number of red component bits.
*/
inline byte rBits() const {
return (8 - rLoss);
}
/**
* Return the number of green component bits.
*/
inline byte gBits() const {
return (8 - gLoss);
}
/**
* Return the number of blue component bits.
*/
inline byte bBits() const {
return (8 - bLoss);
}
/**
* Return the number of alpha component bits.
*/
inline byte aBits() const {
return (8 - aLoss);
}
/**
* Return the total number of bits for the pixel format.
*/
inline byte bpp() const {
return rBits() + gBits() + bBits() + aBits();
}
/** @} */
/**
* @name Convenience functions for getting color components' maximum values
* @{
*/
/**
* Return the maximum value of red.
*/
inline uint rMax() const {
return (1 << rBits()) - 1;
}
/**
* Return the maximum value of green.
*/
inline uint gMax() const {
return (1 << gBits()) - 1;
}
/**
* Return the maximum value of blue.
*/
inline uint bMax() const {
return (1 << bBits()) - 1;
}
/**
* Return the maximum value of alpha.
*/
inline uint aMax() const {
return (1 << aBits()) - 1;
}
/** @} */
/** Expand a given bit-depth component to a full 8-bit component. @todo is that different from the templates at the beginning? */
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);
default:
break;
}
// Unsupported
return 0;
}
/** Return string representation. */
Common::String toString() const;
};
template<>
inline uint32 PixelFormat::RGBToColorT<ColorMasks<0> >(uint8 r, uint8 g, uint8 b) const {
return RGBToColor(r, g, b);
}
template<>
inline uint32 PixelFormat::ARGBToColorT<ColorMasks<0> >(uint8 a, uint8 r, uint8 g, uint8 b) const {
return ARGBToColor(a, r, g, b);
}
template<>
inline void PixelFormat::colorToRGBT<ColorMasks<0> >(uint32 color, uint8 &r, uint8 &g, uint8 &b) const {
colorToRGB(color, r, g, b);
}
template<>
inline void PixelFormat::colorToARGBT<ColorMasks<0> >(uint32 color, uint8 &a, uint8 &r, uint8 &g, uint8 &b) const {
colorToARGB(color, a, r, g, b);
}
/**
* Convert a 'bitFormat' as defined by one of the ColorMasks
* into a PixelFormat.
*/
template<int bitFormat>
PixelFormat createPixelFormat() {
PixelFormat format;
format.bytesPerPixel = ColorMasks<bitFormat>::kBytesPerPixel;
format.rLoss = 8 - ColorMasks<bitFormat>::kRedBits;
format.gLoss = 8 - ColorMasks<bitFormat>::kGreenBits;
format.bLoss = 8 - ColorMasks<bitFormat>::kBlueBits;
format.aLoss = 8 - ColorMasks<bitFormat>::kAlphaBits;
format.rShift = ColorMasks<bitFormat>::kRedShift;
format.gShift = ColorMasks<bitFormat>::kGreenShift;
format.bShift = ColorMasks<bitFormat>::kBlueShift;
format.aShift = ColorMasks<bitFormat>::kAlphaShift;
return format;
}
/** @} */
} // End of namespace Graphics
#endif
