snes9x/filter/xbrz_tools.h

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2018-02-27 20:39:50 +00:00
// ****************************************************************************
// * This file is part of the xBRZ project. It is distributed under *
// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0 *
// * Copyright (C) Zenju (zenju AT gmx DOT de) - All Rights Reserved *
// * *
// * Additionally and as a special exception, the author gives permission *
// * to link the code of this program with the following libraries *
// * (or with modified versions that use the same licenses), and distribute *
// * linked combinations including the two: MAME, FreeFileSync, Snes9x *
// * You must obey the GNU General Public License in all respects for all of *
// * the code used other than MAME, FreeFileSync, Snes9x. *
// * If you modify this file, you may extend this exception to your version *
// * of the file, but you are not obligated to do so. If you do not wish to *
// * do so, delete this exception statement from your version. *
// ****************************************************************************
#ifndef XBRZ_TOOLS_H_825480175091875
#define XBRZ_TOOLS_H_825480175091875
#include <cassert>
#include <algorithm>
#include <type_traits>
namespace xbrz
{
template <uint32_t N> inline
unsigned char getByte(uint32_t val) { return static_cast<unsigned char>((val >> (8 * N)) & 0xff); }
inline unsigned char getAlpha(uint32_t pix) { return getByte<3>(pix); }
inline unsigned char getRed (uint32_t pix) { return getByte<2>(pix); }
inline unsigned char getGreen(uint32_t pix) { return getByte<1>(pix); }
inline unsigned char getBlue (uint32_t pix) { return getByte<0>(pix); }
inline uint32_t makePixel(unsigned char a, unsigned char r, unsigned char g, unsigned char b) { return (a << 24) | (r << 16) | (g << 8) | b; }
inline uint32_t makePixel( unsigned char r, unsigned char g, unsigned char b) { return (r << 16) | (g << 8) | b; }
inline uint32_t rgb555to888(uint16_t pix) { return ((pix & 0x7C00) << 9) | ((pix & 0x03E0) << 6) | ((pix & 0x001F) << 3); }
inline uint32_t rgb565to888(uint16_t pix) { return ((pix & 0xF800) << 8) | ((pix & 0x07E0) << 5) | ((pix & 0x001F) << 3); }
inline uint16_t rgb888to555(uint32_t pix) { return static_cast<uint16_t>(((pix & 0xF80000) >> 9) | ((pix & 0x00F800) >> 6) | ((pix & 0x0000F8) >> 3)); }
inline uint16_t rgb888to565(uint32_t pix) { return static_cast<uint16_t>(((pix & 0xF80000) >> 8) | ((pix & 0x00FC00) >> 5) | ((pix & 0x0000F8) >> 3)); }
template <class Pix> inline
Pix* byteAdvance(Pix* ptr, int bytes)
{
using PixNonConst = typename std::remove_cv<Pix>::type;
using PixByte = typename std::conditional<std::is_same<Pix, PixNonConst>::value, char, const char>::type;
static_assert(std::is_integral<PixNonConst>::value, "Pix* is expected to be cast-able to char*");
return reinterpret_cast<Pix*>(reinterpret_cast<PixByte*>(ptr) + bytes);
}
//fill block with the given color
template <class Pix> inline
void fillBlock(Pix* trg, int pitch, Pix col, int blockWidth, int blockHeight)
{
//for (int y = 0; y < blockHeight; ++y, trg = byteAdvance(trg, pitch))
// std::fill(trg, trg + blockWidth, col);
for (int y = 0; y < blockHeight; ++y, trg = byteAdvance(trg, pitch))
for (int x = 0; x < blockWidth; ++x)
trg[x] = col;
}
//nearest-neighbor (going over target image - slow for upscaling, since source is read multiple times missing out on cache! Fast for similar image sizes!)
template <class PixSrc, class PixTrg, class PixConverter>
void nearestNeighborScale(const PixSrc* src, int srcWidth, int srcHeight, int srcPitch,
/**/ PixTrg* trg, int trgWidth, int trgHeight, int trgPitch,
int yFirst, int yLast, PixConverter pixCvrt /*convert PixSrc to PixTrg*/)
{
static_assert(std::is_integral<PixSrc>::value, "PixSrc* is expected to be cast-able to char*");
static_assert(std::is_integral<PixTrg>::value, "PixTrg* is expected to be cast-able to char*");
static_assert(std::is_same<decltype(pixCvrt(PixSrc())), PixTrg>::value, "PixConverter returning wrong pixel format");
if (srcPitch < srcWidth * static_cast<int>(sizeof(PixSrc)) ||
trgPitch < trgWidth * static_cast<int>(sizeof(PixTrg)))
{
assert(false);
return;
}
yFirst = std::max(yFirst, 0);
yLast = std::min(yLast, trgHeight);
if (yFirst >= yLast || srcHeight <= 0 || srcWidth <= 0) return;
for (int y = yFirst; y < yLast; ++y)
{
const int ySrc = srcHeight * y / trgHeight;
const PixSrc* const srcLine = byteAdvance(src, ySrc * srcPitch);
PixTrg* const trgLine = byteAdvance(trg, y * trgPitch);
for (int x = 0; x < trgWidth; ++x)
{
const int xSrc = srcWidth * x / trgWidth;
trgLine[x] = pixCvrt(srcLine[xSrc]);
}
}
}
//nearest-neighbor (going over source image - fast for upscaling, since source is read only once
template <class PixSrc, class PixTrg, class PixConverter>
void nearestNeighborScaleOverSource(const PixSrc* src, int srcWidth, int srcHeight, int srcPitch,
/**/ PixTrg* trg, int trgWidth, int trgHeight, int trgPitch,
int yFirst, int yLast, PixConverter pixCvrt /*convert PixSrc to PixTrg*/)
{
static_assert(std::is_integral<PixSrc>::value, "PixSrc* is expected to be cast-able to char*");
static_assert(std::is_integral<PixTrg>::value, "PixTrg* is expected to be cast-able to char*");
static_assert(std::is_same<decltype(pixCvrt(PixSrc())), PixTrg>::value, "PixConverter returning wrong pixel format");
if (srcPitch < srcWidth * static_cast<int>(sizeof(PixSrc)) ||
trgPitch < trgWidth * static_cast<int>(sizeof(PixTrg)))
{
assert(false);
return;
}
yFirst = std::max(yFirst, 0);
yLast = std::min(yLast, srcHeight);
if (yFirst >= yLast || trgWidth <= 0 || trgHeight <= 0) return;
for (int y = yFirst; y < yLast; ++y)
{
//mathematically: ySrc = floor(srcHeight * yTrg / trgHeight)
// => search for integers in: [ySrc, ySrc + 1) * trgHeight / srcHeight
//keep within for loop to support MT input slices!
const int yTrgFirst = ( y * trgHeight + srcHeight - 1) / srcHeight; //=ceil(y * trgHeight / srcHeight)
const int yTrgLast = ((y + 1) * trgHeight + srcHeight - 1) / srcHeight; //=ceil(((y + 1) * trgHeight) / srcHeight)
const int blockHeight = yTrgLast - yTrgFirst;
if (blockHeight > 0)
{
const PixSrc* srcLine = byteAdvance(src, y * srcPitch);
/**/ PixTrg* trgLine = byteAdvance(trg, yTrgFirst * trgPitch);
int xTrgFirst = 0;
for (int x = 0; x < srcWidth; ++x)
{
const int xTrgLast = ((x + 1) * trgWidth + srcWidth - 1) / srcWidth;
const int blockWidth = xTrgLast - xTrgFirst;
if (blockWidth > 0)
{
xTrgFirst = xTrgLast;
const auto trgPix = pixCvrt(srcLine[x]);
fillBlock(trgLine, trgPitch, trgPix, blockWidth, blockHeight);
trgLine += blockWidth;
}
}
}
}
}
template <class PixTrg, class PixConverter>
void bilinearScale(const uint32_t* src, int srcWidth, int srcHeight, int srcPitch,
/**/ PixTrg* trg, int trgWidth, int trgHeight, int trgPitch,
int yFirst, int yLast, PixConverter pixCvrt /*convert uint32_t to PixTrg*/)
{
static_assert(std::is_integral<PixTrg>::value, "PixTrg* is expected to be cast-able to char*");
static_assert(std::is_same<decltype(pixCvrt(uint32_t())), PixTrg>::value, "PixConverter returning wrong pixel format");
if (srcPitch < srcWidth * static_cast<int>(sizeof(uint32_t)) ||
trgPitch < trgWidth * static_cast<int>(sizeof(PixTrg)))
{
assert(false);
return;
}
yFirst = std::max(yFirst, 0);
yLast = std::min(yLast, trgHeight);
if (yFirst >= yLast || srcHeight <= 0 || srcWidth <= 0) return;
const double scaleX = static_cast<double>(trgWidth ) / srcWidth;
const double scaleY = static_cast<double>(trgHeight) / srcHeight;
//perf notes:
// -> double-based calculation is (slightly) faster than float
// -> precalculation gives significant boost; std::vector<> memory allocation is negligible!
struct CoeffsX
{
int x1 = 0;
int x2 = 0;
double xx1 = 0;
double x2x = 0;
};
std::vector<CoeffsX> buf(trgWidth);
for (int x = 0; x < trgWidth; ++x)
{
const int x1 = srcWidth * x / trgWidth;
int x2 = x1 + 1;
if (x2 == srcWidth) --x2;
const double xx1 = x / scaleX - x1;
const double x2x = 1 - xx1;
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CoeffsX tmp;
tmp.x1 = x1;
tmp.x2 = x2;
tmp.xx1 = xx1;
tmp.x2x = x2x;
buf[x] = tmp;
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}
for (int y = yFirst; y < yLast; ++y)
{
const int y1 = srcHeight * y / trgHeight;
int y2 = y1 + 1;
if (y2 == srcHeight) --y2;
const double yy1 = y / scaleY - y1;
const double y2y = 1 - yy1;
const uint32_t* const srcLine = byteAdvance(src, y1 * srcPitch);
const uint32_t* const srcLineNext = byteAdvance(src, y2 * srcPitch);
PixTrg* const trgLine = byteAdvance(trg, y * trgPitch);
for (int x = 0; x < trgWidth; ++x)
{
//perf: do NOT "simplify" the variable layout without measurement!
const int x1 = buf[x].x1;
const int x2 = buf[x].x2;
const double xx1 = buf[x].xx1;
const double x2x = buf[x].x2x;
const double x2xy2y = x2x * y2y;
const double xx1y2y = xx1 * y2y;
const double x2xyy1 = x2x * yy1;
const double xx1yy1 = xx1 * yy1;
auto interpolate = [=](int offset)
{
/*
https://en.wikipedia.org/wiki/Bilinear_interpolation
(c11(x2 - x) + c21(x - x1)) * (y2 - y ) +
(c12(x2 - x) + c22(x - x1)) * (y - y1)
*/
const auto c11 = (srcLine [x1] >> (8 * offset)) & 0xff;
const auto c21 = (srcLine [x2] >> (8 * offset)) & 0xff;
const auto c12 = (srcLineNext[x1] >> (8 * offset)) & 0xff;
const auto c22 = (srcLineNext[x2] >> (8 * offset)) & 0xff;
return c11 * x2xy2y + c21 * xx1y2y +
c12 * x2xyy1 + c22 * xx1yy1;
};
const double bi = interpolate(0);
const double gi = interpolate(1);
const double ri = interpolate(2);
const double ai = interpolate(3);
const auto b = static_cast<uint32_t>(bi + 0.5);
const auto g = static_cast<uint32_t>(gi + 0.5);
const auto r = static_cast<uint32_t>(ri + 0.5);
const auto a = static_cast<uint32_t>(ai + 0.5);
const uint32_t trgPix = (a << 24) | (r << 16) | (g << 8) | b;
trgLine[x] = pixCvrt(trgPix);
}
}
}
}
#endif //XBRZ_TOOLS_H_825480175091875