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snes9x/filter/xbrz.cpp
Nicolas Magré 0ec0f2f38c GTK: update xbrz to 1.2 
Conflicts:
	filter/xbrz.cpp
2015-01-30 14:38:06 +01:00

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// ****************************************************************************
// * This file is part of the HqMAME project. It is distributed under *
// * GNU General Public License: http://www.gnu.org/licenses/gpl.html *
// * 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 MAME library (or with modified *
// * versions of MAME that use the same license as MAME), and distribute *
// * linked combinations including the two. You must obey the GNU General *
// * Public License in all respects for all of the code used other than MAME. *
// * 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. *
// ****************************************************************************
#include "xbrz.h"
#include <cassert>
#include <algorithm>
#ifdef unix
#include <cmath>
#endif
#include <vector>
namespace
{
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 val) { return getByte<3>(val); }
inline unsigned char getRed (uint32_t val) { return getByte<2>(val); }
inline unsigned char getGreen(uint32_t val) { return getByte<1>(val); }
inline unsigned char getBlue (uint32_t val) { return getByte<0>(val); }
template <class T> inline
T abs(T value)
{
//static_assert(std::is_signed<T>::value, "abs() requires signed types");
return value < 0 ? -value : value;
}
const uint32_t redMask = 0xff0000;
const uint32_t greenMask = 0x00ff00;
const uint32_t blueMask = 0x0000ff;
template <unsigned int M, unsigned int N> inline
void alphaBlend(uint32_t& dst, uint32_t col) //blend color over destination with opacity M / N
{
//static_assert(0 < M && M < N && N <= 256, "possible overflow of (col & byte1Mask) * M + (dst & byte1Mask) * (N - M)");
const uint32_t byte1Mask = 0x000000ff;
const uint32_t byte2Mask = 0x0000ff00;
const uint32_t byte3Mask = 0x00ff0000;
const uint32_t byte4Mask = 0xff000000;
dst = (byte1Mask & (((col & byte1Mask) * M + (dst & byte1Mask) * (N - M)) / N)) | //
(byte2Mask & (((col & byte2Mask) * M + (dst & byte2Mask) * (N - M)) / N)) | //this works because next higher 8 bits are free
(byte3Mask & (((col & byte3Mask) * M + (dst & byte3Mask) * (N - M)) / N)) | //
(byte4Mask & (((((col & byte4Mask) >> 8) * M + ((dst & byte4Mask) >> 8) * (N - M)) / N) << 8)); //next 8 bits are not free, so shift
//the last row operating on a potential alpha channel costs only ~1% perf => negligible!
}
//inline
//double fastSqrt(double n)
//{
// __asm //speeds up xBRZ by about 9% compared to std::sqrt which internally uses the same assembler instructions but adds some "fluff"
// {
// fld n
// fsqrt
// }
//}
//
//inline
//uint32_t alphaBlend2(uint32_t pix1, uint32_t pix2, double alpha)
//{
// return (redMask & static_cast<uint32_t>((pix1 & redMask ) * alpha + (pix2 & redMask ) * (1 - alpha))) |
// (greenMask & static_cast<uint32_t>((pix1 & greenMask) * alpha + (pix2 & greenMask) * (1 - alpha))) |
// (blueMask & static_cast<uint32_t>((pix1 & blueMask ) * alpha + (pix2 & blueMask ) * (1 - alpha)));
//}
uint32_t* byteAdvance( uint32_t* ptr, int bytes) { return reinterpret_cast< uint32_t*>(reinterpret_cast< char*>(ptr) + bytes); }
const uint32_t* byteAdvance(const uint32_t* ptr, int bytes) { return reinterpret_cast<const uint32_t*>(reinterpret_cast<const char*>(ptr) + bytes); }
//fill block with the given color
inline
void fillBlock(uint32_t* trg, int pitch, uint32_t 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;
}
inline
void fillBlock(uint32_t* trg, int pitch, uint32_t col, int n) { fillBlock(trg, pitch, col, n, n); }
#ifdef _MSC_VER
#define FORCE_INLINE __forceinline
#elif defined __GNUC__
#define FORCE_INLINE __attribute__((always_inline)) inline
#else
#define FORCE_INLINE inline
#endif
enum RotationDegree //clock-wise
{
ROT_0,
ROT_90,
ROT_180,
ROT_270
};
//calculate input matrix coordinates after rotation at compile time
template <RotationDegree rotDeg, size_t I, size_t J, size_t N>
struct MatrixRotation;
template <size_t I, size_t J, size_t N>
struct MatrixRotation<ROT_0, I, J, N>
{
static const size_t I_old = I;
static const size_t J_old = J;
};
template <RotationDegree rotDeg, size_t I, size_t J, size_t N> //(i, j) = (row, col) indices, N = size of (square) matrix
struct MatrixRotation
{
static const size_t I_old = N - 1 - MatrixRotation<static_cast<RotationDegree>(rotDeg - 1), I, J, N>::J_old; //old coordinates before rotation!
static const size_t J_old = MatrixRotation<static_cast<RotationDegree>(rotDeg - 1), I, J, N>::I_old; //
};
template <size_t N, RotationDegree rotDeg>
class OutputMatrix
{
public:
OutputMatrix(uint32_t* out, int outWidth) : //access matrix area, top-left at position "out" for image with given width
out_(out),
outWidth_(outWidth) {}
template <size_t I, size_t J>
uint32_t& ref() const
{
static const size_t I_old = MatrixRotation<rotDeg, I, J, N>::I_old;
static const size_t J_old = MatrixRotation<rotDeg, I, J, N>::J_old;
return *(out_ + J_old + I_old * outWidth_);
}
private:
uint32_t* out_;
const int outWidth_;
};
template <class T> inline
T square(T value) { return value * value; }
/*
inline
void rgbtoLuv(uint32_t c, double& L, double& u, double& v)
{
//http://www.easyrgb.com/index.php?X=MATH&H=02#text2
double r = getRed (c) / 255.0;
double g = getGreen(c) / 255.0;
double b = getBlue (c) / 255.0;
if ( r > 0.04045 )
r = std::pow(( ( r + 0.055 ) / 1.055 ) , 2.4);
else
r /= 12.92;
if ( g > 0.04045 )
g = std::pow(( ( g + 0.055 ) / 1.055 ) , 2.4);
else
g /= 12.92;
if ( b > 0.04045 )
b = std::pow(( ( b + 0.055 ) / 1.055 ) , 2.4);
else
b /= 12.92;
r *= 100;
g *= 100;
b *= 100;
double x = 0.4124564 * r + 0.3575761 * g + 0.1804375 * b;
double y = 0.2126729 * r + 0.7151522 * g + 0.0721750 * b;
double z = 0.0193339 * r + 0.1191920 * g + 0.9503041 * b;
//---------------------
double var_U = 4 * x / ( x + 15 * y + 3 * z );
double var_V = 9 * y / ( x + 15 * y + 3 * z );
double var_Y = y / 100;
if ( var_Y > 0.008856 ) var_Y = std::pow(var_Y , 1.0/3 );
else var_Y = 7.787 * var_Y + 16.0 / 116;
const double ref_X = 95.047; //Observer= 2<>, Illuminant= D65
const double ref_Y = 100.000;
const double ref_Z = 108.883;
const double ref_U = ( 4 * ref_X ) / ( ref_X + ( 15 * ref_Y ) + ( 3 * ref_Z ) );
const double ref_V = ( 9 * ref_Y ) / ( ref_X + ( 15 * ref_Y ) + ( 3 * ref_Z ) );
L = ( 116 * var_Y ) - 16;
u = 13 * L * ( var_U - ref_U );
v = 13 * L * ( var_V - ref_V );
}
*/
inline
void rgbtoLab(uint32_t c, unsigned char& L, signed char& A, signed char& B)
{
//code: http://www.easyrgb.com/index.php?X=MATH
//test: http://www.workwithcolor.com/color-converter-01.htm
//------RGB to XYZ------
double r = getRed (c) / 255.0;
double g = getGreen(c) / 255.0;
double b = getBlue (c) / 255.0;
r = r > 0.04045 ? std::pow(( r + 0.055 ) / 1.055, 2.4) : r / 12.92;
r = g > 0.04045 ? std::pow(( g + 0.055 ) / 1.055, 2.4) : g / 12.92;
r = b > 0.04045 ? std::pow(( b + 0.055 ) / 1.055, 2.4) : b / 12.92;
r *= 100;
g *= 100;
b *= 100;
double x = 0.4124564 * r + 0.3575761 * g + 0.1804375 * b;
double y = 0.2126729 * r + 0.7151522 * g + 0.0721750 * b;
double z = 0.0193339 * r + 0.1191920 * g + 0.9503041 * b;
//------XYZ to Lab------
const double refX = 95.047; //
const double refY = 100.000; //Observer= 2<>, Illuminant= D65
const double refZ = 108.883; //
double var_X = x / refX;
double var_Y = y / refY;
double var_Z = z / refZ;
var_X = var_X > 0.008856 ? std::pow(var_X, 1.0 / 3) : 7.787 * var_X + 4.0 / 29;
var_Y = var_Y > 0.008856 ? std::pow(var_Y, 1.0 / 3) : 7.787 * var_Y + 4.0 / 29;
var_Z = var_Z > 0.008856 ? std::pow(var_Z, 1.0 / 3) : 7.787 * var_Z + 4.0 / 29;
L = static_cast<unsigned char>(116 * var_Y - 16);
A = static_cast< signed char>(500 * (var_X - var_Y));
B = static_cast< signed char>(200 * (var_Y - var_Z));
};
inline
double distLAB(uint32_t pix1, uint32_t pix2)
{
unsigned char L1 = 0; //[0, 100]
signed char a1 = 0; //[-128, 127]
signed char b1 = 0; //[-128, 127]
rgbtoLab(pix1, L1, a1, b1);
unsigned char L2 = 0;
signed char a2 = 0;
signed char b2 = 0;
rgbtoLab(pix2, L2, a2, b2);
//-----------------------------
//http://www.easyrgb.com/index.php?X=DELT
//Delta E/CIE76
return std::sqrt(square(1.0 * L1 - L2) +
square(1.0 * a1 - a2) +
square(1.0 * b1 - b2));
}
/*
inline
void rgbtoHsl(uint32_t c, double& h, double& s, double& l)
{
//http://www.easyrgb.com/index.php?X=MATH&H=18#text18
const int r = getRed (c);
const int g = getGreen(c);
const int b = getBlue (c);
const int varMin = numeric::min(r, g, b);
const int varMax = numeric::max(r, g, b);
const int delMax = varMax - varMin;
l = (varMax + varMin) / 2.0 / 255.0;
if (delMax == 0) //gray, no chroma...
{
h = 0;
s = 0;
}
else
{
s = l < 0.5 ?
delMax / (1.0 * varMax + varMin) :
delMax / (2.0 * 255 - varMax - varMin);
double delR = ((varMax - r) / 6.0 + delMax / 2.0) / delMax;
double delG = ((varMax - g) / 6.0 + delMax / 2.0) / delMax;
double delB = ((varMax - b) / 6.0 + delMax / 2.0) / delMax;
if (r == varMax)
h = delB - delG;
else if (g == varMax)
h = 1 / 3.0 + delR - delB;
else if (b == varMax)
h = 2 / 3.0 + delG - delR;
if (h < 0)
h += 1;
if (h > 1)
h -= 1;
}
}
inline
double distHSL(uint32_t pix1, uint32_t pix2, double lightningWeight)
{
double h1 = 0;
double s1 = 0;
double l1 = 0;
rgbtoHsl(pix1, h1, s1, l1);
double h2 = 0;
double s2 = 0;
double l2 = 0;
rgbtoHsl(pix2, h2, s2, l2);
//HSL is in cylindric coordinatates where L represents height, S radius, H angle,
//however we interpret the cylinder as a bi-conic solid with top/bottom radius 0, middle radius 1
assert(0 <= h1 && h1 <= 1);
assert(0 <= h2 && h2 <= 1);
double r1 = l1 < 0.5 ?
l1 * 2 :
2 - l1 * 2;
double x1 = r1 * s1 * std::cos(h1 * 2 * numeric::pi);
double y1 = r1 * s1 * std::sin(h1 * 2 * numeric::pi);
double z1 = l1;
double r2 = l2 < 0.5 ?
l2 * 2 :
2 - l2 * 2;
double x2 = r2 * s2 * std::cos(h2 * 2 * numeric::pi);
double y2 = r2 * s2 * std::sin(h2 * 2 * numeric::pi);
double z2 = l2;
return 255 * std::sqrt(square(x1 - x2) + square(y1 - y2) + square(lightningWeight * (z1 - z2)));
}
*/
inline
double distRGB(uint32_t pix1, uint32_t pix2)
{
const double r_diff = static_cast<int>(getRed (pix1)) - getRed (pix2);
const double g_diff = static_cast<int>(getGreen(pix1)) - getGreen(pix2);
const double b_diff = static_cast<int>(getBlue (pix1)) - getBlue (pix2);
//euklidean RGB distance
return std::sqrt(square(r_diff) + square(g_diff) + square(b_diff));
}
inline
double distNonLinearRGB(uint32_t pix1, uint32_t pix2)
{
//non-linear rgb: http://www.compuphase.com/cmetric.htm
const double r_diff = static_cast<int>(getRed (pix1)) - getRed (pix2);
const double g_diff = static_cast<int>(getGreen(pix1)) - getGreen(pix2);
const double b_diff = static_cast<int>(getBlue (pix1)) - getBlue (pix2);
const double r_avg = (static_cast<double>(getRed(pix1)) + getRed(pix2)) / 2;
return std::sqrt((2 + r_avg / 255) * square(r_diff) + 4 * square(g_diff) + (2 + (255 - r_avg) / 255) * square(b_diff));
}
inline
double distYCbCr(uint32_t pix1, uint32_t pix2, double lumaWeight)
{
//http://en.wikipedia.org/wiki/YCbCr#ITU-R_BT.601_conversion
//YCbCr conversion is a matrix multiplication => take advantage of linearity by subtracting first!
const int r_diff = static_cast<int>(getRed (pix1)) - getRed (pix2); //we may delay division by 255 to after matrix multiplication
const int g_diff = static_cast<int>(getGreen(pix1)) - getGreen(pix2); //
const int b_diff = static_cast<int>(getBlue (pix1)) - getBlue (pix2); //substraction for int is noticeable faster than for double!
//const double k_b = 0.0722; //ITU-R BT.709 conversion
//const double k_r = 0.2126; //
const double k_b = 0.0593; //ITU-R BT.2020 conversion
const double k_r = 0.2627; //
const double k_g = 1 - k_b - k_r;
const double scale_b = 0.5 / (1 - k_b);
const double scale_r = 0.5 / (1 - k_r);
const double y = k_r * r_diff + k_g * g_diff + k_b * b_diff; //[!], analog YCbCr!
const double c_b = scale_b * (b_diff - y);
const double c_r = scale_r * (r_diff - y);
//we skip division by 255 to have similar range like other distance functions
return std::sqrt(square(lumaWeight * y) + square(c_b) + square(c_r));
}
struct DistYCbCrBuffer //30% perf boost compared to distYCbCr()!
{
public:
DistYCbCrBuffer() : buffer(256 * 256 * 256)
{
for (uint32_t i = 0; i < 256 * 256 * 256; ++i) //startup time: 114 ms on Intel Core i5 (four cores)
{
const int r_diff = getByte<2>(i) * 2 - 255;
const int g_diff = getByte<1>(i) * 2 - 255;
const int b_diff = getByte<0>(i) * 2 - 255;
const double k_b = 0.0593; //ITU-R BT.2020 conversion
const double k_r = 0.2627; //
const double k_g = 1 - k_b - k_r;
const double scale_b = 0.5 / (1 - k_b);
const double scale_r = 0.5 / (1 - k_r);
const double y = k_r * r_diff + k_g * g_diff + k_b * b_diff; //[!], analog YCbCr!
const double c_b = scale_b * (b_diff - y);
const double c_r = scale_r * (r_diff - y);
buffer[i] = static_cast<float>(std::sqrt(square(y) + square(c_b) + square(c_r)));
}
}
double dist(uint32_t pix1, uint32_t pix2) const
{
//if (pix1 == pix2) -> 8% perf degradation!
// return 0;
//if (pix1 > pix2)
// std::swap(pix1, pix2); -> 30% perf degradation!!!
const int r_diff = static_cast<int>(getRed (pix1)) - getRed (pix2);
const int g_diff = static_cast<int>(getGreen(pix1)) - getGreen(pix2);
const int b_diff = static_cast<int>(getBlue (pix1)) - getBlue (pix2);
return buffer[(((r_diff + 255) / 2) << 16) | //slightly reduce precision (division by 2) to squeeze value into single byte
(((g_diff + 255) / 2) << 8) |
(( b_diff + 255) / 2)];
}
private:
std::vector<float> buffer; //consumes 64 MB memory; using double is 2% faster, but takes 128 MB
} distYCbCrBuffer;
inline
double distYUV(uint32_t pix1, uint32_t pix2, double luminanceWeight)
{
//perf: it's not worthwhile to buffer the YUV-conversion, the direct code is faster by ~ 6%
//since RGB -> YUV conversion is essentially a matrix multiplication, we can calculate the RGB diff before the conversion (distributive property)
const double r_diff = static_cast<int>(getRed (pix1)) - getRed (pix2);
const double g_diff = static_cast<int>(getGreen(pix1)) - getGreen(pix2);
const double b_diff = static_cast<int>(getBlue (pix1)) - getBlue (pix2);
//http://en.wikipedia.org/wiki/YUV#Conversion_to.2Ffrom_RGB
const double w_b = 0.114;
const double w_r = 0.299;
const double w_g = 1 - w_r - w_b;
const double u_max = 0.436;
const double v_max = 0.615;
const double scale_u = u_max / (1 - w_b);
const double scale_v = v_max / (1 - w_r);
double y = w_r * r_diff + w_g * g_diff + w_b * b_diff;//value range: 255 * [-1, 1]
double u = scale_u * (b_diff - y); //value range: 255 * 2 * u_max * [-1, 1]
double v = scale_v * (r_diff - y); //value range: 255 * 2 * v_max * [-1, 1]
#ifndef NDEBUG
const double eps = 0.5;
#endif
assert(abs(y) <= 255 + eps);
assert(abs(u) <= 255 * 2 * u_max + eps);
assert(abs(v) <= 255 * 2 * v_max + eps);
return std::sqrt(square(luminanceWeight * y) + square(u) + square(v));
}
enum BlendType
{
BLEND_NONE = 0,
BLEND_NORMAL, //a normal indication to blend
BLEND_DOMINANT, //a strong indication to blend
//attention: BlendType must fit into the value range of 2 bit!!!
};
struct BlendResult
{
BlendType
/**/blend_f, blend_g,
/**/blend_j, blend_k;
};
struct Kernel_4x4 //kernel for preprocessing step
{
uint32_t
/**/a, b, c, d,
/**/e, f, g, h,
/**/i, j, k, l,
/**/m, n, o, p;
};
#define cdist(pix1, pix2) ColorDistance::dist((pix1), (pix2), cfg.luminanceWeight_)
/*
input kernel area naming convention:
-----------------
| A | B | C | D |
----|---|---|---|
| E | F | G | H | //evaluate the four corners between F, G, J, K
----|---|---|---| //input pixel is at position F
| I | J | K | L |
----|---|---|---|
| M | N | O | P |
-----------------
*/
template <class ColorDistance>
FORCE_INLINE //detect blend direction
BlendResult preProcessCorners(const Kernel_4x4& ker, const xbrz::ScalerCfg& cfg) //result: F, G, J, K corners of "GradientType"
{
BlendResult result = {};
if ((ker.f == ker.g &&
ker.j == ker.k) ||
(ker.f == ker.j &&
ker.g == ker.k))
return result;
//auto dist = [&](uint32_t pix1, uint32_t pix2) { return ColorDistance::dist(pix1, pix2, cfg.luminanceWeight_); };
const int weight = 4;
double jg = cdist(ker.i, ker.f) + cdist(ker.f, ker.c) + cdist(ker.n, ker.k) + cdist(ker.k, ker.h) + weight * cdist(ker.j, ker.g);
double fk = cdist(ker.e, ker.j) + cdist(ker.j, ker.o) + cdist(ker.b, ker.g) + cdist(ker.g, ker.l) + weight * cdist(ker.f, ker.k);
if (jg < fk) //test sample: 70% of values max(jg, fk) / min(jg, fk) are between 1.1 and 3.7 with median being 1.8
{
const bool dominantGradient = cfg.dominantDirectionThreshold * jg < fk;
if (ker.f != ker.g && ker.f != ker.j)
result.blend_f = dominantGradient ? BLEND_DOMINANT : BLEND_NORMAL;
if (ker.k != ker.j && ker.k != ker.g)
result.blend_k = dominantGradient ? BLEND_DOMINANT : BLEND_NORMAL;
}
else if (fk < jg)
{
const bool dominantGradient = cfg.dominantDirectionThreshold * fk < jg;
if (ker.j != ker.f && ker.j != ker.k)
result.blend_j = dominantGradient ? BLEND_DOMINANT : BLEND_NORMAL;
if (ker.g != ker.f && ker.g != ker.k)
result.blend_g = dominantGradient ? BLEND_DOMINANT : BLEND_NORMAL;
}
return result;
}
struct Kernel_3x3
{
uint32_t
/**/a, b, c,
/**/d, e, f,
/**/g, h, i;
};
#define DEF_GETTER(x) template <RotationDegree rotDeg> uint32_t inline get_##x(const Kernel_3x3& ker) { return ker.x; }
//we cannot and NEED NOT write "ker.##x" since ## concatenates preprocessor tokens but "." is not a token
DEF_GETTER(a) DEF_GETTER(b) DEF_GETTER(c)
DEF_GETTER(d) DEF_GETTER(e) DEF_GETTER(f)
DEF_GETTER(g) DEF_GETTER(h) DEF_GETTER(i)
#undef DEF_GETTER
#define DEF_GETTER(x, y) template <> inline uint32_t get_##x<ROT_90>(const Kernel_3x3& ker) { return ker.y; }
DEF_GETTER(a, g) DEF_GETTER(b, d) DEF_GETTER(c, a)
DEF_GETTER(d, h) DEF_GETTER(e, e) DEF_GETTER(f, b)
DEF_GETTER(g, i) DEF_GETTER(h, f) DEF_GETTER(i, c)
#undef DEF_GETTER
#define DEF_GETTER(x, y) template <> inline uint32_t get_##x<ROT_180>(const Kernel_3x3& ker) { return ker.y; }
DEF_GETTER(a, i) DEF_GETTER(b, h) DEF_GETTER(c, g)
DEF_GETTER(d, f) DEF_GETTER(e, e) DEF_GETTER(f, d)
DEF_GETTER(g, c) DEF_GETTER(h, b) DEF_GETTER(i, a)
#undef DEF_GETTER
#define DEF_GETTER(x, y) template <> inline uint32_t get_##x<ROT_270>(const Kernel_3x3& ker) { return ker.y; }
DEF_GETTER(a, c) DEF_GETTER(b, f) DEF_GETTER(c, i)
DEF_GETTER(d, b) DEF_GETTER(e, e) DEF_GETTER(f, h)
DEF_GETTER(g, a) DEF_GETTER(h, d) DEF_GETTER(i, g)
#undef DEF_GETTER
//compress four blend types into a single byte
inline BlendType getTopL (unsigned char b) { return static_cast<BlendType>(0x3 & b); }
inline BlendType getTopR (unsigned char b) { return static_cast<BlendType>(0x3 & (b >> 2)); }
inline BlendType getBottomR(unsigned char b) { return static_cast<BlendType>(0x3 & (b >> 4)); }
inline BlendType getBottomL(unsigned char b) { return static_cast<BlendType>(0x3 & (b >> 6)); }
inline void setTopL (unsigned char& b, BlendType bt) { b |= bt; } //buffer is assumed to be initialized before preprocessing!
inline void setTopR (unsigned char& b, BlendType bt) { b |= (bt << 2); }
inline void setBottomR(unsigned char& b, BlendType bt) { b |= (bt << 4); }
inline void setBottomL(unsigned char& b, BlendType bt) { b |= (bt << 6); }
inline bool blendingNeeded(unsigned char b) { return b != 0; }
template <RotationDegree rotDeg> inline
unsigned char rotateBlendInfo(unsigned char b) { return b; }
template <> inline unsigned char rotateBlendInfo<ROT_90 >(unsigned char b) { return ((b << 2) | (b >> 6)) & 0xff; }
template <> inline unsigned char rotateBlendInfo<ROT_180>(unsigned char b) { return ((b << 4) | (b >> 4)) & 0xff; }
template <> inline unsigned char rotateBlendInfo<ROT_270>(unsigned char b) { return ((b << 6) | (b >> 2)) & 0xff; }
#ifndef NDEBUG
int debugPixelX = -1;
int debugPixelY = 84;
bool breakIntoDebugger = false;
#endif
#define eq(pix1, pix2) (ColorDistance::dist((pix1), (pix2), cfg.luminanceWeight_) < cfg.equalColorTolerance_)
/*
input kernel area naming convention:
-------------
| A | B | C |
----|---|---|
| D | E | F | //input pixel is at position E
----|---|---|
| G | H | I |
-------------
*/
template <class Scaler, class ColorDistance, RotationDegree rotDeg>
FORCE_INLINE //perf: quite worth it!
void blendPixel(const Kernel_3x3& ker,
uint32_t* target, int trgWidth,
unsigned char blendInfo, //result of preprocessing all four corners of pixel "e"
const xbrz::ScalerCfg& cfg)
{
#define a get_a<rotDeg>(ker)
#define b get_b<rotDeg>(ker)
#define c get_c<rotDeg>(ker)
#define d get_d<rotDeg>(ker)
#define e get_e<rotDeg>(ker)
#define f get_f<rotDeg>(ker)
#define g get_g<rotDeg>(ker)
#define h get_h<rotDeg>(ker)
#define i get_i<rotDeg>(ker)
#ifdef WIN32
# ifndef NDEBUG
if (breakIntoDebugger)
__debugbreak(); //__asm int 3;
# endif
#endif
const unsigned char blend = rotateBlendInfo<rotDeg>(blendInfo);
if (getBottomR(blend) >= BLEND_NORMAL)
{
//auto eq = [&](uint32_t pix1, uint32_t pix2) { return ColorDistance::dist(pix1, pix2, cfg.luminanceWeight_) < cfg.equalColorTolerance_; };
//auto dist = [&](uint32_t pix1, uint32_t pix2) { return ColorDistance::dist(pix1, pix2, cfg.luminanceWeight_); };
bool doLineBlend = true;
if (getBottomR(blend) >= BLEND_DOMINANT)
doLineBlend = true;
//make sure there is no second blending in an adjacent rotation for this pixel: handles insular pixels, mario eyes
else if (getTopR(blend) != BLEND_NONE && !eq(e, g)) //but support double-blending for 90<39> corners
doLineBlend = false;
else if(getBottomL(blend) != BLEND_NONE && !eq(e, c))
doLineBlend = false;
//no full blending for L-shapes; blend corner only (handles "mario mushroom eyes")
else if (!eq(e, i) && eq(g, h) && eq(h , i) && eq(i, f) && eq(f, c))
doLineBlend = false;
else
doLineBlend = true;
const uint32_t px = cdist(e, f) <= cdist(e, h) ? f : h; //choose most similar color
OutputMatrix<Scaler::scale, rotDeg> out(target, trgWidth);
if (doLineBlend)
{
const double fg = cdist(f, g); //test sample: 70% of values max(fg, hc) / min(fg, hc) are between 1.1 and 3.7 with median being 1.9
const double hc = cdist(h, c); //
const bool haveShallowLine = cfg.steepDirectionThreshold * fg <= hc && e != g && d != g;
const bool haveSteepLine = cfg.steepDirectionThreshold * hc <= fg && e != c && b != c;
if (haveShallowLine)
{
if (haveSteepLine)
Scaler::blendLineSteepAndShallow(px, out);
else
Scaler::blendLineShallow(px, out);
}
else
{
if (haveSteepLine)
Scaler::blendLineSteep(px, out);
else
Scaler::blendLineDiagonal(px,out);
}
}
else
Scaler::blendCorner(px, out);
}
#undef a
#undef b
#undef c
#undef d
#undef e
#undef f
#undef g
#undef h
#undef i
}
template <class Scaler, class ColorDistance> //scaler policy: see "Scaler2x" reference implementation
void scaleImage(const uint32_t* src, uint32_t* trg, int srcWidth, int srcHeight, const xbrz::ScalerCfg& cfg, int yFirst, int yLast)
{
yFirst = std::max(yFirst, 0);
yLast = std::min(yLast, srcHeight);
if (yFirst >= yLast || srcWidth <= 0)
return;
const int trgWidth = srcWidth * Scaler::scale;
//"use" space at the end of the image as temporary buffer for "on the fly preprocessing": we even could use larger area of
//"sizeof(uint32_t) * srcWidth * (yLast - yFirst)" bytes without risk of accidental overwriting before accessing
const int bufferSize = srcWidth;
unsigned char* preProcBuffer = reinterpret_cast<unsigned char*>(trg + yLast * Scaler::scale * trgWidth) - bufferSize;
std::fill(preProcBuffer, preProcBuffer + bufferSize, 0);
//static_assert(BLEND_NONE == 0, "");
//initialize preprocessing buffer for first row of current stripe: detect upper left and right corner blending
//this cannot be optimized for adjacent processing stripes; we must not allow for a memory race condition!
if (yFirst > 0)
{
const int y = yFirst - 1;
const uint32_t* s_m1 = src + srcWidth * std::max(y - 1, 0);
const uint32_t* s_0 = src + srcWidth * y; //center line
const uint32_t* s_p1 = src + srcWidth * std::min(y + 1, srcHeight - 1);
const uint32_t* s_p2 = src + srcWidth * std::min(y + 2, srcHeight - 1);
for (int x = 0; x < srcWidth; ++x)
{
const int x_m1 = std::max(x - 1, 0);
const int x_p1 = std::min(x + 1, srcWidth - 1);
const int x_p2 = std::min(x + 2, srcWidth - 1);
Kernel_4x4 ker = {}; //perf: initialization is negligible
ker.a = s_m1[x_m1]; //read sequentially from memory as far as possible
ker.b = s_m1[x];
ker.c = s_m1[x_p1];
ker.d = s_m1[x_p2];
ker.e = s_0[x_m1];
ker.f = s_0[x];
ker.g = s_0[x_p1];
ker.h = s_0[x_p2];
ker.i = s_p1[x_m1];
ker.j = s_p1[x];
ker.k = s_p1[x_p1];
ker.l = s_p1[x_p2];
ker.m = s_p2[x_m1];
ker.n = s_p2[x];
ker.o = s_p2[x_p1];
ker.p = s_p2[x_p2];
const BlendResult res = preProcessCorners<ColorDistance>(ker, cfg);
/*
preprocessing blend result:
---------
| F | G | //evalute corner between F, G, J, K
----|---| //input pixel is at position F
| J | K |
---------
*/
setTopR(preProcBuffer[x], res.blend_j);
if (x + 1 < bufferSize)
setTopL(preProcBuffer[x + 1], res.blend_k);
}
}
//------------------------------------------------------------------------------------
for (int y = yFirst; y < yLast; ++y)
{
uint32_t* out = trg + Scaler::scale * y * trgWidth; //consider MT "striped" access
const uint32_t* s_m1 = src + srcWidth * std::max(y - 1, 0);
const uint32_t* s_0 = src + srcWidth * y; //center line
const uint32_t* s_p1 = src + srcWidth * std::min(y + 1, srcHeight - 1);
const uint32_t* s_p2 = src + srcWidth * std::min(y + 2, srcHeight - 1);
unsigned char blend_xy1 = 0; //corner blending for current (x, y + 1) position
for (int x = 0; x < srcWidth; ++x, out += Scaler::scale)
{
#ifndef NDEBUG
breakIntoDebugger = debugPixelX == x && debugPixelY == y;
#endif
//all those bounds checks have only insignificant impact on performance!
const int x_m1 = std::max(x - 1, 0); //perf: prefer array indexing to additional pointers!
const int x_p1 = std::min(x + 1, srcWidth - 1);
const int x_p2 = std::min(x + 2, srcWidth - 1);
Kernel_4x4 ker4 = {}; //perf: initialization is negligible
ker4.a = s_m1[x_m1]; //read sequentially from memory as far as possible
ker4.b = s_m1[x];
ker4.c = s_m1[x_p1];
ker4.d = s_m1[x_p2];
ker4.e = s_0[x_m1];
ker4.f = s_0[x];
ker4.g = s_0[x_p1];
ker4.h = s_0[x_p2];
ker4.i = s_p1[x_m1];
ker4.j = s_p1[x];
ker4.k = s_p1[x_p1];
ker4.l = s_p1[x_p2];
ker4.m = s_p2[x_m1];
ker4.n = s_p2[x];
ker4.o = s_p2[x_p1];
ker4.p = s_p2[x_p2];
//evaluate the four corners on bottom-right of current pixel
unsigned char blend_xy = 0; //for current (x, y) position
{
const BlendResult res = preProcessCorners<ColorDistance>(ker4, cfg);
/*
preprocessing blend result:
---------
| F | G | //evalute corner between F, G, J, K
----|---| //current input pixel is at position F
| J | K |
---------
*/
blend_xy = preProcBuffer[x];
setBottomR(blend_xy, res.blend_f); //all four corners of (x, y) have been determined at this point due to processing sequence!
setTopR(blend_xy1, res.blend_j); //set 2nd known corner for (x, y + 1)
preProcBuffer[x] = blend_xy1; //store on current buffer position for use on next row
blend_xy1 = 0;
setTopL(blend_xy1, res.blend_k); //set 1st known corner for (x + 1, y + 1) and buffer for use on next column
if (x + 1 < bufferSize) //set 3rd known corner for (x + 1, y)
setBottomL(preProcBuffer[x + 1], res.blend_g);
}
//fill block of size scale * scale with the given color
fillBlock(out, trgWidth * sizeof(uint32_t), ker4.f, Scaler::scale); //place *after* preprocessing step, to not overwrite the results while processing the the last pixel!
//blend four corners of current pixel
if (blendingNeeded(blend_xy)) //good 5% perf-improvement
{
Kernel_3x3 ker3 = {}; //perf: initialization is negligible
ker3.a = ker4.a;
ker3.b = ker4.b;
ker3.c = ker4.c;
ker3.d = ker4.e;
ker3.e = ker4.f;
ker3.f = ker4.g;
ker3.g = ker4.i;
ker3.h = ker4.j;
ker3.i = ker4.k;
blendPixel<Scaler, ColorDistance, ROT_0 >(ker3, out, trgWidth, blend_xy, cfg);
blendPixel<Scaler, ColorDistance, ROT_90 >(ker3, out, trgWidth, blend_xy, cfg);
blendPixel<Scaler, ColorDistance, ROT_180>(ker3, out, trgWidth, blend_xy, cfg);
blendPixel<Scaler, ColorDistance, ROT_270>(ker3, out, trgWidth, blend_xy, cfg);
}
}
}
}
//------------------------------------------------------------------------------------
struct Scaler2x
{
static const int scale = 2;
template <class OutputMatrix>
static void blendLineShallow(uint32_t col, OutputMatrix& out)
{
alphaBlend<1, 4>(out.template ref<scale - 1, 0>(), col);
alphaBlend<3, 4>(out.template ref<scale - 1, 1>(), col);
}
template <class OutputMatrix>
static void blendLineSteep(uint32_t col, OutputMatrix& out)
{
alphaBlend<1, 4>(out.template ref<0, scale - 1>(), col);
alphaBlend<3, 4>(out.template ref<1, scale - 1>(), col);
}
template <class OutputMatrix>
static void blendLineSteepAndShallow(uint32_t col, OutputMatrix& out)
{
alphaBlend<1, 4>(out.template ref<1, 0>(), col);
alphaBlend<1, 4>(out.template ref<0, 1>(), col);
alphaBlend<5, 6>(out.template ref<1, 1>(), col); //[!] fixes 7/8 used in xBR
}
template <class OutputMatrix>
static void blendLineDiagonal(uint32_t col, OutputMatrix& out)
{
alphaBlend<1, 2>(out.template ref<1, 1>(), col);
}
template <class OutputMatrix>
static void blendCorner(uint32_t col, OutputMatrix& out)
{
//model a round corner
alphaBlend<21, 100>(out.template ref<1, 1>(), col); //exact: 1 - pi/4 = 0.2146018366
}
};
struct Scaler3x
{
static const int scale = 3;
template <class OutputMatrix>
static void blendLineShallow(uint32_t col, OutputMatrix& out)
{
alphaBlend<1, 4>(out.template ref<scale - 1, 0>(), col);
alphaBlend<1, 4>(out.template ref<scale - 2, 2>(), col);
alphaBlend<3, 4>(out.template ref<scale - 1, 1>(), col);
out.template ref<scale - 1, 2>() = col;
}
template <class OutputMatrix>
static void blendLineSteep(uint32_t col, OutputMatrix& out)
{
alphaBlend<1, 4>(out.template ref<0, scale - 1>(), col);
alphaBlend<1, 4>(out.template ref<2, scale - 2>(), col);
alphaBlend<3, 4>(out.template ref<1, scale - 1>(), col);
out.template ref<2, scale - 1>() = col;
}
template <class OutputMatrix>
static void blendLineSteepAndShallow(uint32_t col, OutputMatrix& out)
{
alphaBlend<1, 4>(out.template ref<2, 0>(), col);
alphaBlend<1, 4>(out.template ref<0, 2>(), col);
alphaBlend<3, 4>(out.template ref<2, 1>(), col);
alphaBlend<3, 4>(out.template ref<1, 2>(), col);
out.template ref<2, 2>() = col;
}
template <class OutputMatrix>
static void blendLineDiagonal(uint32_t col, OutputMatrix& out)
{
alphaBlend<1, 8>(out.template ref<1, 2>(), col);
alphaBlend<1, 8>(out.template ref<2, 1>(), col);
alphaBlend<7, 8>(out.template ref<2, 2>(), col);
}
template <class OutputMatrix>
static void blendCorner(uint32_t col, OutputMatrix& out)
{
//model a round corner
alphaBlend<45, 100>(out.template ref<2, 2>(), col); //exact: 0.4545939598
//alphaBlend<14, 1000>(out.template ref<2, 1>(), col); //0.01413008627 -> negligible
//alphaBlend<14, 1000>(out.template ref<1, 2>(), col); //0.01413008627
}
};
struct Scaler4x
{
static const int scale = 4;
template <class OutputMatrix>
static void blendLineShallow(uint32_t col, OutputMatrix& out)
{
alphaBlend<1, 4>(out.template ref<scale - 1, 0>(), col);
alphaBlend<1, 4>(out.template ref<scale - 2, 2>(), col);
alphaBlend<3, 4>(out.template ref<scale - 1, 1>(), col);
alphaBlend<3, 4>(out.template ref<scale - 2, 3>(), col);
out.template ref<scale - 1, 2>() = col;
out.template ref<scale - 1, 3>() = col;
}
template <class OutputMatrix>
static void blendLineSteep(uint32_t col, OutputMatrix& out)
{
alphaBlend<1, 4>(out.template ref<0, scale - 1>(), col);
alphaBlend<1, 4>(out.template ref<2, scale - 2>(), col);
alphaBlend<3, 4>(out.template ref<1, scale - 1>(), col);
alphaBlend<3, 4>(out.template ref<3, scale - 2>(), col);
out.template ref<2, scale - 1>() = col;
out.template ref<3, scale - 1>() = col;
}
template <class OutputMatrix>
static void blendLineSteepAndShallow(uint32_t col, OutputMatrix& out)
{
alphaBlend<3, 4>(out.template ref<3, 1>(), col);
alphaBlend<3, 4>(out.template ref<1, 3>(), col);
alphaBlend<1, 4>(out.template ref<3, 0>(), col);
alphaBlend<1, 4>(out.template ref<0, 3>(), col);
alphaBlend<1, 3>(out.template ref<2, 2>(), col); //[!] fixes 1/4 used in xBR
out.template ref<3, 3>() = out.template ref<3, 2>() = out.template ref<2, 3>() = col;
}
template <class OutputMatrix>
static void blendLineDiagonal(uint32_t col, OutputMatrix& out)
{
alphaBlend<1, 2>(out.template ref<scale - 1, scale / 2 >(), col);
alphaBlend<1, 2>(out.template ref<scale - 2, scale / 2 + 1>(), col);
out.template ref<scale - 1, scale - 1>() = col;
}
template <class OutputMatrix>
static void blendCorner(uint32_t col, OutputMatrix& out)
{
//model a round corner
alphaBlend<68, 100>(out.template ref<3, 3>(), col); //exact: 0.6848532563
alphaBlend< 9, 100>(out.template ref<3, 2>(), col); //0.08677704501
alphaBlend< 9, 100>(out.template ref<2, 3>(), col); //0.08677704501
}
};
struct Scaler5x
{
static const int scale = 5;
template <class OutputMatrix>
static void blendLineShallow(uint32_t col, OutputMatrix& out)
{
alphaBlend<1, 4>(out.template ref<scale - 1, 0>(), col);
alphaBlend<1, 4>(out.template ref<scale - 2, 2>(), col);
alphaBlend<1, 4>(out.template ref<scale - 3, 4>(), col);
alphaBlend<3, 4>(out.template ref<scale - 1, 1>(), col);
alphaBlend<3, 4>(out.template ref<scale - 2, 3>(), col);
out.template ref<scale - 1, 2>() = col;
out.template ref<scale - 1, 3>() = col;
out.template ref<scale - 1, 4>() = col;
out.template ref<scale - 2, 4>() = col;
}
template <class OutputMatrix>
static void blendLineSteep(uint32_t col, OutputMatrix& out)
{
alphaBlend<1, 4>(out.template ref<0, scale - 1>(), col);
alphaBlend<1, 4>(out.template ref<2, scale - 2>(), col);
alphaBlend<1, 4>(out.template ref<4, scale - 3>(), col);
alphaBlend<3, 4>(out.template ref<1, scale - 1>(), col);
alphaBlend<3, 4>(out.template ref<3, scale - 2>(), col);
out.template ref<2, scale - 1>() = col;
out.template ref<3, scale - 1>() = col;
out.template ref<4, scale - 1>() = col;
out.template ref<4, scale - 2>() = col;
}
template <class OutputMatrix>
static void blendLineSteepAndShallow(uint32_t col, OutputMatrix& out)
{
alphaBlend<1, 4>(out.template ref<0, scale - 1>(), col);
alphaBlend<1, 4>(out.template ref<2, scale - 2>(), col);
alphaBlend<3, 4>(out.template ref<1, scale - 1>(), col);
alphaBlend<1, 4>(out.template ref<scale - 1, 0>(), col);
alphaBlend<1, 4>(out.template ref<scale - 2, 2>(), col);
alphaBlend<3, 4>(out.template ref<scale - 1, 1>(), col);
out.template ref<2, scale - 1>() = col;
out.template ref<3, scale - 1>() = col;
out.template ref<scale - 1, 2>() = col;
out.template ref<scale - 1, 3>() = col;
out.template ref<4, scale - 1>() = col;
alphaBlend<2, 3>(out.template ref<3, 3>(), col);
}
template <class OutputMatrix>
static void blendLineDiagonal(uint32_t col, OutputMatrix& out)
{
alphaBlend<1, 8>(out.template ref<scale - 1, scale / 2 >(), col);
alphaBlend<1, 8>(out.template ref<scale - 2, scale / 2 + 1>(), col);
alphaBlend<1, 8>(out.template ref<scale - 3, scale / 2 + 2>(), col);
alphaBlend<7, 8>(out.template ref<4, 3>(), col);
alphaBlend<7, 8>(out.template ref<3, 4>(), col);
out.template ref<4, 4>() = col;
}
template <class OutputMatrix>
static void blendCorner(uint32_t col, OutputMatrix& out)
{
//model a round corner
alphaBlend<86, 100>(out.template ref<4, 4>(), col); //exact: 0.8631434088
alphaBlend<23, 100>(out.template ref<4, 3>(), col); //0.2306749731
alphaBlend<23, 100>(out.template ref<3, 4>(), col); //0.2306749731
//alphaBlend<8, 1000>(out.template ref<4, 2>(), col); //0.008384061834 -> negligible
//alphaBlend<8, 1000>(out.template ref<2, 4>(), col); //0.008384061834
}
};
//------------------------------------------------------------------------------------
struct ColorDistanceRGB
{
static double dist(uint32_t pix1, uint32_t pix2, double luminanceWeight)
{
return distYCbCrBuffer.dist(pix1, pix2);
//if (pix1 == pix2) //about 4% perf boost
// return 0;
//return distYCbCr(pix1, pix2, luminanceWeight);
}
};
struct ColorDistanceARGB
{
static double dist(uint32_t pix1, uint32_t pix2, double luminanceWeight)
{
const double a1 = getAlpha(pix1) / 255.0 ;
const double a2 = getAlpha(pix2) / 255.0 ;
/*
Requirements for a color distance handling alpha channel: with a1, a2 in [0, 1]
1. if a1 = a2, distance should be: a1 * distYCbCr()
2. if a1 = 0, distance should be: a2 * distYCbCr(black, white) = a2 * 255
3. if a1 = 1, distance should be: 255 * (1 - a2) + a2 * distYCbCr()
*/
return std::min(a1, a2) * distYCbCrBuffer.dist(pix1, pix2) + 255 * abs(a1 - a2);
//if (pix1 == pix2)
// return 0;
//return std::min(a1, a2) * distYCbCr(pix1, pix2, luminanceWeight) + 255 * abs(a1 - a2);
}
};
}
void xbrz::scale(size_t factor, const uint32_t* src, uint32_t* trg, int srcWidth, int srcHeight, ColorFormat colFmt, const xbrz::ScalerCfg& cfg, int yFirst, int yLast)
{
switch (colFmt)
{
#ifdef WIN32
case ColorFormat::ARGB:// not Standard C++.
#else
case ARGB:
#endif
switch (factor)
{
case 2:
return scaleImage<Scaler2x, ColorDistanceARGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast);
case 3:
return scaleImage<Scaler3x, ColorDistanceARGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast);
case 4:
return scaleImage<Scaler4x, ColorDistanceARGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast);
case 5:
return scaleImage<Scaler5x, ColorDistanceARGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast);
}
break;
#ifdef WIN32
case ColorFormat::RGB:// not Standard C++.
#else
case RGB:
#endif
switch (factor)
{
case 2:
return scaleImage<Scaler2x, ColorDistanceRGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast);
case 3:
return scaleImage<Scaler3x, ColorDistanceRGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast);
case 4:
return scaleImage<Scaler4x, ColorDistanceRGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast);
case 5:
return scaleImage<Scaler5x, ColorDistanceRGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast);
}
break;
}
assert(false);
}
bool xbrz::equalColorTest(uint32_t col1, uint32_t col2, ColorFormat colFmt, double luminanceWeight, double equalColorTolerance)
{
switch (colFmt)
{
#ifdef WIN32
case ColorFormat::ARGB: // not Standard C++.
#else
case ARGB:
#endif
return ColorDistanceARGB::dist(col1, col2, luminanceWeight) < equalColorTolerance;
#ifdef WIN32
case ColorFormat::RGB:// not Standard C++.
#else
case RGB:
#endif
return ColorDistanceRGB::dist(col1, col2, luminanceWeight) < equalColorTolerance;
}
assert(false);
return false;
}
void xbrz::nearestNeighborScale(const uint32_t* src, int srcWidth, int srcHeight, int srcPitch,
uint32_t* trg, int trgWidth, int trgHeight, int trgPitch,
SliceType st, int yFirst, int yLast)
{
if (srcPitch < srcWidth * static_cast<int>(sizeof(uint32_t)) ||
trgPitch < trgWidth * static_cast<int>(sizeof(uint32_t)))
{
assert(false);
return;
}
switch (st)
{
case NN_SCALE_SLICE_SOURCE:
//nearest-neighbor (going over source image - fast for upscaling, since source is read only once
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 yTrg_first = ( y * trgHeight + srcHeight - 1) / srcHeight; //=ceil(y * trgHeight / srcHeight)
const int yTrg_last = ((y + 1) * trgHeight + srcHeight - 1) / srcHeight; //=ceil(((y + 1) * trgHeight) / srcHeight)
const int blockHeight = yTrg_last - yTrg_first;
if (blockHeight > 0)
{
const uint32_t* srcLine = byteAdvance(src, y * srcPitch);
uint32_t* trgLine = byteAdvance(trg, yTrg_first * trgPitch);
int xTrg_first = 0;
for (int x = 0; x < srcWidth; ++x)
{
int xTrg_last = ((x + 1) * trgWidth + srcWidth - 1) / srcWidth;
const int blockWidth = xTrg_last - xTrg_first;
if (blockWidth > 0)
{
xTrg_first = xTrg_last;
fillBlock(trgLine, trgPitch, srcLine[x], blockWidth, blockHeight);
trgLine += blockWidth;
}
}
}
}
break;
case NN_SCALE_SLICE_TARGET:
//nearest-neighbor (going over target image - slow for upscaling, since source is read multiple times missing out on cache! Fast for similar image sizes!)
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)
{
uint32_t* trgLine = byteAdvance(trg, y * trgPitch);
const int ySrc = srcHeight * y / trgHeight;
const uint32_t* srcLine = byteAdvance(src, ySrc * srcPitch);
for (int x = 0; x < trgWidth; ++x)
{
const int xSrc = srcWidth * x / trgWidth;
trgLine[x] = srcLine[xSrc];
}
}
break;
}
}
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