SuperImposedFrame.cc

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#include "SuperImposedFrame.hh"
#include "PixelOperations.hh"
#include "LineScalers.hh"
#include "unreachable.hh"
#include "vla.hh"
#include "build-info.hh"
#include <algorithm>
#include <concepts>
#include <cstdint>
#include <memory>
 
namespace openmsx {
 
template<std::unsigned_integral Pixel>
class SuperImposedFrameImpl final : public SuperImposedFrame
{
public:
        explicit SuperImposedFrameImpl(const PixelFormat& format);
 
private:
        [[nodiscard]] unsigned getLineWidth(unsigned line) const override;
        [[nodiscard]] const void* getLineInfo(
                unsigned line, unsigned& width,
                void* buf, unsigned bufWidth) const override;
 
        PixelOperations<Pixel> pixelOps;
};
 
 
// class SuperImposedFrame
 
std::unique_ptr<SuperImposedFrame> SuperImposedFrame::create(
        const PixelFormat& format)
{
#if HAVE_16BPP
        if (format.getBytesPerPixel() == 2) {
                return std::make_unique<SuperImposedFrameImpl<uint16_t>>(format);
        }
#endif
#if HAVE_32BPP
        if (format.getBytesPerPixel() == 4) {
                return std::make_unique<SuperImposedFrameImpl<uint32_t>>(format);
        }
#endif
        UNREACHABLE; return nullptr; // avoid warning
}
 
SuperImposedFrame::SuperImposedFrame(const PixelFormat& format)
        : FrameSource(format)
{
}
 
void SuperImposedFrame::init(
        const FrameSource* top_, const FrameSource* bottom_)
{
        top = top_;
        bottom = bottom_;
        setHeight(std::max(top->getHeight(), bottom->getHeight()));
}
 
 
// class SuperImposedFrameImpl
 
template<std::unsigned_integral Pixel>
SuperImposedFrameImpl<Pixel>::SuperImposedFrameImpl(
                const PixelFormat& format)
        : SuperImposedFrame(format)
        , pixelOps(format)
{
}
 
template<std::unsigned_integral Pixel>
unsigned SuperImposedFrameImpl<Pixel>::getLineWidth(unsigned line) const
{
        unsigned tNum = (getHeight() == top   ->getHeight()) ? line : line / 2;
        unsigned bNum = (getHeight() == bottom->getHeight()) ? line : line / 2;
        unsigned tWidth = top   ->getLineWidth(tNum);
        unsigned bWidth = bottom->getLineWidth(bNum);
        return std::max(tWidth, bWidth);
}
 
template<std::unsigned_integral Pixel>
const void* SuperImposedFrameImpl<Pixel>::getLineInfo(
        unsigned line, unsigned& width, void* buf, unsigned bufWidth) const
{
        unsigned tNum = (getHeight() == top   ->getHeight()) ? line : line / 2;
        unsigned bNum = (getHeight() == bottom->getHeight()) ? line : line / 2;
        unsigned tWidth = top   ->getLineWidth(tNum);
        unsigned bWidth = bottom->getLineWidth(bNum);
        width = std::max(tWidth, bWidth);  // as wide as the widest source
        width = std::min(width, bufWidth); // but no wider than the output buffer
 
        auto tBuf = std::span{static_cast<Pixel*>(buf), width};
        VLA_SSE_ALIGNED(Pixel, bBuf, width);
        auto tLine = top   ->getLine(tNum, tBuf);
        auto bLine = bottom->getLine(bNum, bBuf);
 
        AlphaBlendLines<Pixel> blend(pixelOps);
        blend(tLine, bLine, tBuf); // possibly tLine == tBuf
        return tBuf.data();
}
 
} // namespace openmsx