Scale3xScaler.cc

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/*
Original code: Copyright (C) 2001-2003 Andrea Mazzoleni
openMSX adaptation by Maarten ter Huurne
 
This file is based on code from the Scale2x project.
This modified version is licensed under GPL; the original code is dual-licensed
under GPL and under a custom license.
 
Visit the Scale2x site for info:
  http://scale2x.sourceforge.net/
*/
 
#include "Scale3xScaler.hh"
#include "FrameSource.hh"
#include "ScalerOutput.hh"
#include "narrow.hh"
#include "vla.hh"
#include "xrange.hh"
#include "build-info.hh"
#include <cstdint>
 
namespace openmsx {
 
template<std::unsigned_integral Pixel>
Scale3xScaler<Pixel>::Scale3xScaler(const PixelOperations<Pixel>& pixelOps_)
        : Scaler3<Pixel>(pixelOps_)
{
}
 
template<std::unsigned_integral Pixel>
void Scale3xScaler<Pixel>::scaleLine1on3Half(
        std::span<Pixel> dst,
        std::span<const Pixel> src0, std::span<const Pixel> src1, std::span<const Pixel> src2)
{
        auto srcWidth = src0.size();
        assert(src0.size() == srcWidth);
        assert(src1.size() == srcWidth);
        assert(src2.size() == srcWidth);
        assert(dst.size() == 3 * srcWidth);
        /* A B C
         * D E F
         * G H I
         *
         * E0 =  D == B && B != F && D != H ? D : E;
         * E1 = (D == B && B != F && D != H && E != C) ||
         *      (B == F && B != D && F != H && E != A) ? B : E;
         * E2 = B == F && B != D && F != H ? F : E;
         */
 
        // First pixel.
        Pixel top   = src0[0];
        Pixel mid   = src1[0];
        Pixel right = src1[1];
        Pixel bot   = src2[0];
 
        dst[0] = mid;
        dst[1] = (mid != right) && (top != bot) &&
                 (((top == mid) && (mid != src0[1])) ||
                  ((top == right) && (mid != top)))
               ? top : mid;
        dst[2] = (mid != right) && (top != bot) && (top == right)
               ? top : mid;
 
        // Central pixels.
        for (auto x : xrange(1u, srcWidth - 1)) {
                Pixel left = mid;
                mid   = right;
                right = src1[x + 1];
                top = src0[x];
                bot = src2[x];
                dst[3 * x + 0] = (left != right) && (top != bot) &&
                                 (top == left)
                               ? top : mid;
                dst[3 * x + 1] = (left != right) && (top != bot) &&
                                 (((top == left ) && (mid != src0[x + 1])) ||
                                  ((top == right) && (mid != src0[x - 1])))
                               ? top : mid;
                dst[3 * x + 2] = (left != right) && (top != bot) &&
                                 (top == right)
                               ? top : mid;
        }
 
        // Last pixel.
        Pixel left = mid;
        mid = right;
        top = src0[srcWidth - 1];
        bot = src2[srcWidth - 1];
        dst[3 * srcWidth - 3] = (left != mid) && (top != bot) && (top ==left)
                 ? top : mid;
        dst[3 * srcWidth - 2] = (left != mid) && (top != bot) &&
                   (((top == left) && (mid != top)) ||
                    ((top == mid ) && (mid != src0[srcWidth - 2])))
                 ? top : mid;
        dst[3 * srcWidth - 1] = mid;
}
 
template<std::unsigned_integral Pixel>
void Scale3xScaler<Pixel>::scaleLine1on3Mid(
        std::span<Pixel> dst,
        std::span<const Pixel> src0, std::span<const Pixel> src1, std::span<const Pixel> src2)
{
        auto srcWidth = src0.size();
        assert(src0.size() == srcWidth);
        assert(src1.size() == srcWidth);
        assert(src2.size() == srcWidth);
        assert(dst.size() == 3 * srcWidth);
        /*
         * A B C
         * D E F
         * G H I
         *
         * E3 = (D == B && B != F && D != H && E != G) ||
         *      (D == H && D != B && H != F && E != A) ? D : E;
         * E4 = E
         * E5 = (B == F && B != D && F != H && E != I) ||
         *      (H == F && D != H && B != F && E != C) ? F : E;
         */
 
        // First pixel.
        Pixel mid   = src1[0];
        Pixel right = src1[1];
        Pixel top = src0[0];
        Pixel bot = src2[0];
        dst[0] = mid;
        dst[1] = mid;
        dst[2] = (mid != right) && (top != bot) &&
                 (((right == top) && (mid != src2[1])) ||
                  ((right == bot) && (mid != src0[1])))
               ? right : mid;
 
        // Central pixels.
        for (auto x : xrange(1u, srcWidth - 1)) {
                Pixel left = mid;
                mid   = right;
                right = src1[x + 1];
                top = src0[x];
                bot = src2[x];
                dst[3 * x + 0] = (left != right) && (top != bot) &&
                                 (((left == top) && (mid != src2[x - 1])) ||
                                  ((left == bot) && (mid != src0[x - 1])))
                               ? left : mid;
                dst[3 * x + 1] = mid;
                dst[3 * x + 2] = (left != right) && (top != bot) &&
                                 (((right == top) && (mid != src2[x + 1])) ||
                                  ((right == bot) && (mid != src0[x + 1])))
                               ? right : mid;
        }
 
        // Last pixel.
        Pixel left = mid;
        mid   = right;
        top = src0[srcWidth - 1];
        bot = src2[srcWidth - 1];
        dst[3 * srcWidth - 3] = (left != mid) && (top != bot) &&
                   (((left == top) && (mid != src2[srcWidth - 2])) ||
                    ((left == bot) && (mid != src0[srcWidth - 2])))
                 ? left : mid;
        dst[3 * srcWidth - 2] = mid;
        dst[3 * srcWidth - 1] = mid;
}
 
template<std::unsigned_integral Pixel>
void Scale3xScaler<Pixel>::scale1x1to3x3(FrameSource& src,
        unsigned srcStartY, unsigned /*srcEndY*/, unsigned srcWidth,
        ScalerOutput<Pixel>& dst, unsigned dstStartY, unsigned dstEndY)
{
        VLA_SSE_ALIGNED(Pixel, buf0, srcWidth);
        VLA_SSE_ALIGNED(Pixel, buf1, srcWidth);
        VLA_SSE_ALIGNED(Pixel, buf2, srcWidth);
 
        auto srcY = narrow<int>(srcStartY);
        auto srcPrev = src.getLine(srcY - 1, buf0);
        auto srcCurr = src.getLine(srcY + 0, buf1);
 
        for (unsigned dstY = dstStartY; dstY < dstEndY; srcY += 1, dstY += 3) {
                auto srcNext = src.getLine(srcY + 1, buf2);
 
                auto dstUpper  = dst.acquireLine(dstY + 0);
                scaleLine1on3Half(dstUpper, srcPrev, srcCurr, srcNext);
                dst.releaseLine(dstY + 0, dstUpper);
 
                auto dstMiddle = dst.acquireLine(dstY + 1);
                scaleLine1on3Mid(dstMiddle, srcPrev, srcCurr, srcNext);
                dst.releaseLine(dstY + 1, dstMiddle);
 
                auto dstLower  = dst.acquireLine(dstY + 2);
                scaleLine1on3Half(dstLower, srcNext, srcCurr, srcPrev);
                dst.releaseLine(dstY + 2, dstLower);
 
                srcPrev = srcCurr;
                srcCurr = srcNext;
                std::swap(buf0, buf1);
                std::swap(buf1, buf2);
        }
}
 
// Force template instantiation.
#if HAVE_16BPP
template class Scale3xScaler<uint16_t>;
#endif
#if HAVE_32BPP
template class Scale3xScaler<uint32_t>;
#endif
 
} // namespace openmsx