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Diffstat (limited to 'xBRZ/src/xbrz.cpp')
| -rwxr-xr-x | xBRZ/src/xbrz.cpp | 1262 |
1 files changed, 1262 insertions, 0 deletions
diff --git a/xBRZ/src/xbrz.cpp b/xBRZ/src/xbrz.cpp new file mode 100755 index 00000000..4d3ccd25 --- /dev/null +++ b/xBRZ/src/xbrz.cpp @@ -0,0 +1,1262 @@ +// **************************************************************************** +// * 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, ePSXe * +// * You must obey the GNU General Public License in all respects for all of * +// * the code used other than MAME, FreeFileSync, Snes9x, ePSXe. * +// * 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 <vector> +#include <algorithm> +#include <cmath> //std::sqrt +#include "xbrz_tools.h" + +using namespace xbrz; + + +namespace +{ +template <unsigned int M, unsigned int N> inline +uint32_t gradientRGB(uint32_t pixFront, uint32_t pixBack) //blend front color with opacity M / N over opaque background: http://en.wikipedia.org/wiki/Alpha_compositing#Alpha_blending +{ + static_assert(0 < M && M < N && N <= 1000, ""); + + auto calcColor = [](unsigned char colFront, unsigned char colBack) -> unsigned char { return (colFront * M + colBack * (N - M)) / N; }; + + return makePixel(calcColor(getRed (pixFront), getRed (pixBack)), + calcColor(getGreen(pixFront), getGreen(pixBack)), + calcColor(getBlue (pixFront), getBlue (pixBack))); +} + + +template <unsigned int M, unsigned int N> inline +uint32_t gradientARGB(uint32_t pixFront, uint32_t pixBack) //find intermediate color between two colors with alpha channels (=> NO alpha blending!!!) +{ + static_assert(0 < M && M < N && N <= 1000, ""); + + const unsigned int weightFront = getAlpha(pixFront) * M; + const unsigned int weightBack = getAlpha(pixBack) * (N - M); + const unsigned int weightSum = weightFront + weightBack; + if (weightSum == 0) + return 0; + + auto calcColor = [=](unsigned char colFront, unsigned char colBack) + { + return static_cast<unsigned char>((colFront * weightFront + colBack * weightBack) / weightSum); + }; + + return makePixel(static_cast<unsigned char>(weightSum / N), + calcColor(getRed (pixFront), getRed (pixBack)), + calcColor(getGreen(pixFront), getGreen(pixBack)), + calcColor(getBlue (pixFront), getBlue (pixBack))); +} + + +//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 +// } +//} +// + + +#if 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; } + + +#if 0 +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)); +} +#endif + + +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)); +} + + +inline +double distYCbCrBuffered(uint32_t pix1, uint32_t pix2) +{ + //30% perf boost compared to plain distYCbCr()! + //consumes 64 MB memory; using double is only 2% faster, but takes 128 MB + static const std::vector<float> diffToDist = [] + { + std::vector<float> tmp; + + for (uint32_t i = 0; i < 256 * 256 * 256; ++i) //startup time: 114 ms on Intel Core i5 (four cores) + { + const int r_diff = static_cast<signed char>(getByte<2>(i)) * 2; + const int g_diff = static_cast<signed char>(getByte<1>(i)) * 2; + const int b_diff = static_cast<signed char>(getByte<0>(i)) * 2; + + 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); + + tmp.push_back(static_cast<float>(std::sqrt(square(y) + square(c_b) + square(c_r)))); + } + return tmp; + }(); + + //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); + + const size_t index = (static_cast<unsigned char>(r_diff / 2) << 16) | //slightly reduce precision (division by 2) to squeeze value into single byte + (static_cast<unsigned char>(g_diff / 2) << 8) | + (static_cast<unsigned char>(b_diff / 2)); + +#if 0 //attention: the following calculation creates an asymmetric color distance!!! (e.g. r_diff=46 will be unpacked as 45, but r_diff=-46 unpacks to -47 + const size_t index = (((r_diff + 0xFF) / 2) << 16) | //slightly reduce precision (division by 2) to squeeze value into single byte + (((g_diff + 0xFF) / 2) << 8) | + (( b_diff + 0xFF) / 2); +#endif + return diffToDist[index]; +} + + +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; +}; + +/* +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); }; + + double jg = dist(ker.i, ker.f) + dist(ker.f, ker.c) + dist(ker.n, ker.k) + dist(ker.k, ker.h) + cfg.centerDirectionBias * dist(ker.j, ker.g); + double fk = dist(ker.e, ker.j) + dist(ker.j, ker.o) + dist(ker.b, ker.g) + dist(ker.g, ker.l) + cfg.centerDirectionBias * dist(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; } + + + + +/* +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) + + + (void)a; //silence Clang's -Wunused-function + + 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); }; + + const bool doLineBlend = [&]() -> bool + { + if (getBottomR(blend) >= BLEND_DOMINANT) + return true; + + //make sure there is no second blending in an adjacent rotation for this pixel: handles insular pixels, mario eyes + if (getTopR(blend) != BLEND_NONE && !eq(e, g)) //but support double-blending for 90° corners + return false; + if (getBottomL(blend) != BLEND_NONE && !eq(e, c)) + return false; + + //no full blending for L-shapes; blend corner only (handles "mario mushroom eyes") + if (!eq(e, i) && eq(g, h) && eq(h, i) && eq(i, f) && eq(f, c)) + return false; + + return true; + }(); + + const uint32_t px = dist(e, f) <= dist(e, h) ? f : h; //choose most similar color + + OutputMatrix<Scaler::scale, rotDeg> out(target, trgWidth); + + if (doLineBlend) + { + const double fg = dist(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 = dist(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) + { + //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, 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); + } + } + } +} + +//------------------------------------------------------------------------------------ + +template <class ColorGradient> +struct Scaler2x : public ColorGradient +{ + static const int scale = 2; + + template <unsigned int M, unsigned int N> //bring template function into scope for GCC + static void alphaGrad(uint32_t& pixBack, uint32_t pixFront) { ColorGradient::template alphaGrad<M, N>(pixBack, pixFront); } + + + template <class OutputMatrix> + static void blendLineShallow(uint32_t col, OutputMatrix& out) + { + alphaGrad<1, 4>(out.template ref<scale - 1, 0>(), col); + alphaGrad<3, 4>(out.template ref<scale - 1, 1>(), col); + } + + template <class OutputMatrix> + static void blendLineSteep(uint32_t col, OutputMatrix& out) + { + alphaGrad<1, 4>(out.template ref<0, scale - 1>(), col); + alphaGrad<3, 4>(out.template ref<1, scale - 1>(), col); + } + + template <class OutputMatrix> + static void blendLineSteepAndShallow(uint32_t col, OutputMatrix& out) + { + alphaGrad<1, 4>(out.template ref<1, 0>(), col); + alphaGrad<1, 4>(out.template ref<0, 1>(), col); + alphaGrad<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) + { + alphaGrad<1, 2>(out.template ref<1, 1>(), col); + } + + template <class OutputMatrix> + static void blendCorner(uint32_t col, OutputMatrix& out) + { + //model a round corner + alphaGrad<21, 100>(out.template ref<1, 1>(), col); //exact: 1 - pi/4 = 0.2146018366 + } +}; + + +template <class ColorGradient> +struct Scaler3x : public ColorGradient +{ + static const int scale = 3; + + template <unsigned int M, unsigned int N> //bring template function into scope for GCC + static void alphaGrad(uint32_t& pixBack, uint32_t pixFront) { ColorGradient::template alphaGrad<M, N>(pixBack, pixFront); } + + + template <class OutputMatrix> + static void blendLineShallow(uint32_t col, OutputMatrix& out) + { + alphaGrad<1, 4>(out.template ref<scale - 1, 0>(), col); + alphaGrad<1, 4>(out.template ref<scale - 2, 2>(), col); + + alphaGrad<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) + { + alphaGrad<1, 4>(out.template ref<0, scale - 1>(), col); + alphaGrad<1, 4>(out.template ref<2, scale - 2>(), col); + + alphaGrad<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) + { + alphaGrad<1, 4>(out.template ref<2, 0>(), col); + alphaGrad<1, 4>(out.template ref<0, 2>(), col); + alphaGrad<3, 4>(out.template ref<2, 1>(), col); + alphaGrad<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) + { + alphaGrad<1, 8>(out.template ref<1, 2>(), col); //conflict with other rotations for this odd scale + alphaGrad<1, 8>(out.template ref<2, 1>(), col); + alphaGrad<7, 8>(out.template ref<2, 2>(), col); // + } + + template <class OutputMatrix> + static void blendCorner(uint32_t col, OutputMatrix& out) + { + //model a round corner + alphaGrad<45, 100>(out.template ref<2, 2>(), col); //exact: 0.4545939598 + //alphaGrad<7, 256>(out.template ref<2, 1>(), col); //0.02826017254 -> negligible + avoid conflicts with other rotations for this odd scale + //alphaGrad<7, 256>(out.template ref<1, 2>(), col); //0.02826017254 + } +}; + + +template <class ColorGradient> +struct Scaler4x : public ColorGradient +{ + static const int scale = 4; + + template <unsigned int M, unsigned int N> //bring template function into scope for GCC + static void alphaGrad(uint32_t& pixBack, uint32_t pixFront) { ColorGradient::template alphaGrad<M, N>(pixBack, pixFront); } + + + template <class OutputMatrix> + static void blendLineShallow(uint32_t col, OutputMatrix& out) + { + alphaGrad<1, 4>(out.template ref<scale - 1, 0>(), col); + alphaGrad<1, 4>(out.template ref<scale - 2, 2>(), col); + + alphaGrad<3, 4>(out.template ref<scale - 1, 1>(), col); + alphaGrad<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) + { + alphaGrad<1, 4>(out.template ref<0, scale - 1>(), col); + alphaGrad<1, 4>(out.template ref<2, scale - 2>(), col); + + alphaGrad<3, 4>(out.template ref<1, scale - 1>(), col); + alphaGrad<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) + { + alphaGrad<3, 4>(out.template ref<3, 1>(), col); + alphaGrad<3, 4>(out.template ref<1, 3>(), col); + alphaGrad<1, 4>(out.template ref<3, 0>(), col); + alphaGrad<1, 4>(out.template ref<0, 3>(), col); + + alphaGrad<1, 3>(out.template ref<2, 2>(), col); //[!] fixes 1/4 used in xBR + + out.template ref<3, 3>() = col; + out.template ref<3, 2>() = col; + out.template ref<2, 3>() = col; + } + + template <class OutputMatrix> + static void blendLineDiagonal(uint32_t col, OutputMatrix& out) + { + alphaGrad<1, 2>(out.template ref<scale - 1, scale / 2 >(), col); + alphaGrad<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 + alphaGrad<68, 100>(out.template ref<3, 3>(), col); //exact: 0.6848532563 + alphaGrad< 9, 100>(out.template ref<3, 2>(), col); //0.08677704501 + alphaGrad< 9, 100>(out.template ref<2, 3>(), col); //0.08677704501 + } +}; + + +template <class ColorGradient> +struct Scaler5x : public ColorGradient +{ + static const int scale = 5; + + template <unsigned int M, unsigned int N> //bring template function into scope for GCC + static void alphaGrad(uint32_t& pixBack, uint32_t pixFront) { ColorGradient::template alphaGrad<M, N>(pixBack, pixFront); } + + + template <class OutputMatrix> + static void blendLineShallow(uint32_t col, OutputMatrix& out) + { + alphaGrad<1, 4>(out.template ref<scale - 1, 0>(), col); + alphaGrad<1, 4>(out.template ref<scale - 2, 2>(), col); + alphaGrad<1, 4>(out.template ref<scale - 3, 4>(), col); + + alphaGrad<3, 4>(out.template ref<scale - 1, 1>(), col); + alphaGrad<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) + { + alphaGrad<1, 4>(out.template ref<0, scale - 1>(), col); + alphaGrad<1, 4>(out.template ref<2, scale - 2>(), col); + alphaGrad<1, 4>(out.template ref<4, scale - 3>(), col); + + alphaGrad<3, 4>(out.template ref<1, scale - 1>(), col); + alphaGrad<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) + { + alphaGrad<1, 4>(out.template ref<0, scale - 1>(), col); + alphaGrad<1, 4>(out.template ref<2, scale - 2>(), col); + alphaGrad<3, 4>(out.template ref<1, scale - 1>(), col); + + alphaGrad<1, 4>(out.template ref<scale - 1, 0>(), col); + alphaGrad<1, 4>(out.template ref<scale - 2, 2>(), col); + alphaGrad<3, 4>(out.template ref<scale - 1, 1>(), col); + + alphaGrad<2, 3>(out.template ref<3, 3>(), 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<scale - 1, 2>() = col; + out.template ref<scale - 1, 3>() = col; + } + + template <class OutputMatrix> + static void blendLineDiagonal(uint32_t col, OutputMatrix& out) + { + alphaGrad<1, 8>(out.template ref<scale - 1, scale / 2 >(), col); //conflict with other rotations for this odd scale + alphaGrad<1, 8>(out.template ref<scale - 2, scale / 2 + 1>(), col); + alphaGrad<1, 8>(out.template ref<scale - 3, scale / 2 + 2>(), col); // + + alphaGrad<7, 8>(out.template ref<4, 3>(), col); + alphaGrad<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 + alphaGrad<86, 100>(out.template ref<4, 4>(), col); //exact: 0.8631434088 + alphaGrad<23, 100>(out.template ref<4, 3>(), col); //0.2306749731 + alphaGrad<23, 100>(out.template ref<3, 4>(), col); //0.2306749731 + //alphaGrad<1, 64>(out.template ref<4, 2>(), col); //0.01676812367 -> negligible + avoid conflicts with other rotations for this odd scale + //alphaGrad<1, 64>(out.template ref<2, 4>(), col); //0.01676812367 + } +}; + + +template <class ColorGradient> +struct Scaler6x : public ColorGradient +{ + static const int scale = 6; + + template <unsigned int M, unsigned int N> //bring template function into scope for GCC + static void alphaGrad(uint32_t& pixBack, uint32_t pixFront) { ColorGradient::template alphaGrad<M, N>(pixBack, pixFront); } + + + template <class OutputMatrix> + static void blendLineShallow(uint32_t col, OutputMatrix& out) + { + alphaGrad<1, 4>(out.template ref<scale - 1, 0>(), col); + alphaGrad<1, 4>(out.template ref<scale - 2, 2>(), col); + alphaGrad<1, 4>(out.template ref<scale - 3, 4>(), col); + + alphaGrad<3, 4>(out.template ref<scale - 1, 1>(), col); + alphaGrad<3, 4>(out.template ref<scale - 2, 3>(), col); + alphaGrad<3, 4>(out.template ref<scale - 3, 5>(), 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 - 1, 5>() = col; + + out.template ref<scale - 2, 4>() = col; + out.template ref<scale - 2, 5>() = col; + } + + template <class OutputMatrix> + static void blendLineSteep(uint32_t col, OutputMatrix& out) + { + alphaGrad<1, 4>(out.template ref<0, scale - 1>(), col); + alphaGrad<1, 4>(out.template ref<2, scale - 2>(), col); + alphaGrad<1, 4>(out.template ref<4, scale - 3>(), col); + + alphaGrad<3, 4>(out.template ref<1, scale - 1>(), col); + alphaGrad<3, 4>(out.template ref<3, scale - 2>(), col); + alphaGrad<3, 4>(out.template ref<5, scale - 3>(), 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<5, scale - 1>() = col; + + out.template ref<4, scale - 2>() = col; + out.template ref<5, scale - 2>() = col; + } + + template <class OutputMatrix> + static void blendLineSteepAndShallow(uint32_t col, OutputMatrix& out) + { + alphaGrad<1, 4>(out.template ref<0, scale - 1>(), col); + alphaGrad<1, 4>(out.template ref<2, scale - 2>(), col); + alphaGrad<3, 4>(out.template ref<1, scale - 1>(), col); + alphaGrad<3, 4>(out.template ref<3, scale - 2>(), col); + + alphaGrad<1, 4>(out.template ref<scale - 1, 0>(), col); + alphaGrad<1, 4>(out.template ref<scale - 2, 2>(), col); + alphaGrad<3, 4>(out.template ref<scale - 1, 1>(), col); + alphaGrad<3, 4>(out.template ref<scale - 2, 3>(), 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<5, scale - 1>() = col; + + out.template ref<4, scale - 2>() = col; + out.template ref<5, scale - 2>() = col; + + out.template ref<scale - 1, 2>() = col; + out.template ref<scale - 1, 3>() = col; + } + + template <class OutputMatrix> + static void blendLineDiagonal(uint32_t col, OutputMatrix& out) + { + alphaGrad<1, 2>(out.template ref<scale - 1, scale / 2 >(), col); + alphaGrad<1, 2>(out.template ref<scale - 2, scale / 2 + 1>(), col); + alphaGrad<1, 2>(out.template ref<scale - 3, scale / 2 + 2>(), col); + + out.template ref<scale - 2, scale - 1>() = col; + out.template ref<scale - 1, scale - 1>() = col; + out.template ref<scale - 1, scale - 2>() = col; + } + + template <class OutputMatrix> + static void blendCorner(uint32_t col, OutputMatrix& out) + { + //model a round corner + alphaGrad<97, 100>(out.template ref<5, 5>(), col); //exact: 0.9711013910 + alphaGrad<42, 100>(out.template ref<4, 5>(), col); //0.4236372243 + alphaGrad<42, 100>(out.template ref<5, 4>(), col); //0.4236372243 + alphaGrad< 6, 100>(out.template ref<5, 3>(), col); //0.05652034508 + alphaGrad< 6, 100>(out.template ref<3, 5>(), col); //0.05652034508 + } +}; + +//------------------------------------------------------------------------------------ + +struct ColorDistanceRGB +{ + static double dist(uint32_t pix1, uint32_t pix2, double luminanceWeight) + { + return distYCbCrBuffered(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, ??? maybe: 255 * (1 - a2) + a2 * distYCbCr() + */ + + //return std::min(a1, a2) * distYCbCrBuffered(pix1, pix2) + 255 * abs(a1 - a2); + //=> following code is 15% faster: + const double d = distYCbCrBuffered(pix1, pix2); + if (a1 < a2) + return a1 * d + 255 * (a2 - a1); + else + return a2 * d + 255 * (a1 - a2); + + //alternative? return std::sqrt(a1 * a2 * square(distYCbCrBuffered(pix1, pix2)) + square(255 * (a1 - a2))); + } +}; + + +struct ColorDistanceUnbufferedARGB +{ + 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 ; + + const double d = distYCbCr(pix1, pix2, luminanceWeight); + if (a1 < a2) + return a1 * d + 255 * (a2 - a1); + else + return a2 * d + 255 * (a1 - a2); + } +}; + + +struct ColorGradientRGB +{ + template <unsigned int M, unsigned int N> + static void alphaGrad(uint32_t& pixBack, uint32_t pixFront) + { + pixBack = gradientRGB<M, N>(pixFront, pixBack); + } +}; + +struct ColorGradientARGB +{ + template <unsigned int M, unsigned int N> + static void alphaGrad(uint32_t& pixBack, uint32_t pixFront) + { + pixBack = gradientARGB<M, N>(pixFront, pixBack); + } +}; +} + + +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) +{ +if (factor == 1) + { + std::copy(src + yFirst * srcWidth, src + yLast * srcWidth, trg); + return; + } + + static_assert(SCALE_FACTOR_MAX == 6, ""); + switch (colFmt) + { + case ColorFormat::RGB: + switch (factor) + { + case 2: + return scaleImage<Scaler2x<ColorGradientRGB>, ColorDistanceRGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast); + case 3: + return scaleImage<Scaler3x<ColorGradientRGB>, ColorDistanceRGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast); + case 4: + return scaleImage<Scaler4x<ColorGradientRGB>, ColorDistanceRGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast); + case 5: + return scaleImage<Scaler5x<ColorGradientRGB>, ColorDistanceRGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast); + case 6: + return scaleImage<Scaler6x<ColorGradientRGB>, ColorDistanceRGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast); + } + break; + + case ColorFormat::ARGB: + switch (factor) + { + case 2: + return scaleImage<Scaler2x<ColorGradientARGB>, ColorDistanceARGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast); + case 3: + return scaleImage<Scaler3x<ColorGradientARGB>, ColorDistanceARGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast); + case 4: + return scaleImage<Scaler4x<ColorGradientARGB>, ColorDistanceARGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast); + case 5: + return scaleImage<Scaler5x<ColorGradientARGB>, ColorDistanceARGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast); + case 6: + return scaleImage<Scaler6x<ColorGradientARGB>, ColorDistanceARGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast); + } + break; + + case ColorFormat::ARGB_UNBUFFERED: + switch (factor) + { + case 2: + return scaleImage<Scaler2x<ColorGradientARGB>, ColorDistanceUnbufferedARGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast); + case 3: + return scaleImage<Scaler3x<ColorGradientARGB>, ColorDistanceUnbufferedARGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast); + case 4: + return scaleImage<Scaler4x<ColorGradientARGB>, ColorDistanceUnbufferedARGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast); + case 5: + return scaleImage<Scaler5x<ColorGradientARGB>, ColorDistanceUnbufferedARGB>(src, trg, srcWidth, srcHeight, cfg, yFirst, yLast); + case 6: + return scaleImage<Scaler6x<ColorGradientARGB>, ColorDistanceUnbufferedARGB>(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) + { + case ColorFormat::RGB: + return ColorDistanceRGB::dist(col1, col2, luminanceWeight) < equalColorTolerance; + case ColorFormat::ARGB: + return ColorDistanceARGB::dist(col1, col2, luminanceWeight) < equalColorTolerance; + case ColorFormat::ARGB_UNBUFFERED: + return ColorDistanceUnbufferedARGB::dist(col1, col2, luminanceWeight) < equalColorTolerance; + } + assert(false); + return false; +} + + +void xbrz::bilinearScale(const uint32_t* src, int srcWidth, int srcHeight, + /**/ uint32_t* trg, int trgWidth, int trgHeight) +{ + bilinearScale(src, srcWidth, srcHeight, srcWidth * sizeof(uint32_t), + trg, trgWidth, trgHeight, trgWidth * sizeof(uint32_t), + 0, trgHeight, [](uint32_t pix) { return pix; }); +} + + +void xbrz::nearestNeighborScale(const uint32_t* src, int srcWidth, int srcHeight, + /**/ uint32_t* trg, int trgWidth, int trgHeight) +{ + nearestNeighborScale(src, srcWidth, srcHeight, srcWidth * sizeof(uint32_t), + trg, trgWidth, trgHeight, trgWidth * sizeof(uint32_t), + 0, trgHeight, [](uint32_t pix) { return pix; }); +} + + +#if 0 +//#include <ppl.h> +void bilinearScaleCpu(const uint32_t* src, int srcWidth, int srcHeight, + /**/ uint32_t* trg, int trgWidth, int trgHeight) +{ + const int TASK_GRANULARITY = 16; + + concurrency::task_group tg; + + for (int i = 0; i < trgHeight; i += TASK_GRANULARITY) + tg.run([=] + { + const int iLast = std::min(i + TASK_GRANULARITY, trgHeight); + xbrz::bilinearScale(src, srcWidth, srcHeight, srcWidth * sizeof(uint32_t), + trg, trgWidth, trgHeight, trgWidth * sizeof(uint32_t), + i, iLast, [](uint32_t pix) { return pix; }); + }); + tg.wait(); +} + + +//Perf: AMP vs CPU: merely ~10% shorter runtime (scaling 1280x800 -> 1920x1080) +//#include <amp.h> +void bilinearScaleAmp(const uint32_t* src, int srcWidth, int srcHeight, //throw concurrency::runtime_exception + /**/ uint32_t* trg, int trgWidth, int trgHeight) +{ + //C++ AMP reference: https://msdn.microsoft.com/en-us/library/hh289390.aspx + //introduction to C++ AMP: https://msdn.microsoft.com/en-us/magazine/hh882446.aspx + using namespace concurrency; + //TODO: pitch + + if (srcHeight <= 0 || srcWidth <= 0) return; + + const float scaleX = static_cast<float>(trgWidth ) / srcWidth; + const float scaleY = static_cast<float>(trgHeight) / srcHeight; + + array_view<const uint32_t, 2> srcView(srcHeight, srcWidth, src); + array_view< uint32_t, 2> trgView(trgHeight, trgWidth, trg); + trgView.discard_data(); + + parallel_for_each(trgView.extent, [=](index<2> idx) restrict(amp) //throw ? + { + const int y = idx[0]; + const int x = idx[1]; + //Perf notes: + // -> float-based calculation is (almost) 2x as fas as double! + // -> no noticeable improvement via tiling: https://msdn.microsoft.com/en-us/magazine/hh882447.aspx + // -> no noticeable improvement with restrict(amp,cpu) + // -> iterating over y-axis only is significantly slower! + // -> pre-calculating x,y-dependent variables in a buffer + array_view<> is ~ 20 % slower! + const int y1 = srcHeight * y / trgHeight; + int y2 = y1 + 1; + if (y2 == srcHeight) --y2; + + const float yy1 = y / scaleY - y1; + const float y2y = 1 - yy1; + //------------------------------------- + const int x1 = srcWidth * x / trgWidth; + int x2 = x1 + 1; + if (x2 == srcWidth) --x2; + + const float xx1 = x / scaleX - x1; + const float x2x = 1 - xx1; + //------------------------------------- + const float x2xy2y = x2x * y2y; + const float xx1y2y = xx1 * y2y; + const float x2xyy1 = x2x * yy1; + const float 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 = (srcView(y1, x1) >> (8 * offset)) & 0xff; + const auto c21 = (srcView(y1, x2) >> (8 * offset)) & 0xff; + const auto c12 = (srcView(y2, x1) >> (8 * offset)) & 0xff; + const auto c22 = (srcView(y2, x2) >> (8 * offset)) & 0xff; + + return c11 * x2xy2y + c21 * xx1y2y + + c12 * x2xyy1 + c22 * xx1yy1; + }; + + const float bi = interpolate(0); + const float gi = interpolate(1); + const float ri = interpolate(2); + const float ai = interpolate(3); + + const auto b = static_cast<uint32_t>(bi + 0.5f); + const auto g = static_cast<uint32_t>(gi + 0.5f); + const auto r = static_cast<uint32_t>(ri + 0.5f); + const auto a = static_cast<uint32_t>(ai + 0.5f); + + trgView(y, x) = (a << 24) | (r << 16) | (g << 8) | b; + }); + trgView.synchronize(); //throw ? +} +#endif |