C++ Iterator::z方法代码示例

static bool
checker_ (ImageBuf &dst, Dim3 size,
          const float *color1, const float *color2,
          Dim3 offset,
          ROI roi, int nthreads=1)
{
    if (nthreads != 1 && roi.npixels() >= 1000) {
        // Lots of pixels and request for multi threads? Parallelize.
        ImageBufAlgo::parallel_image (
            OIIO::bind(checker_<T>, OIIO::ref(dst),
                        size, color1, color2, offset,
                        _1 /*roi*/, 1 /*nthreads*/),
            roi, nthreads);
        return true;
    }

    // Serial case
    for (ImageBuf::Iterator<T> p (dst, roi);  !p.done();  ++p) {
        int xtile = (p.x()-offset.x)/size.x;  xtile += (p.x()<offset.x);
        int ytile = (p.y()-offset.y)/size.y;  ytile += (p.y()<offset.y);
        int ztile = (p.z()-offset.z)/size.z;  ztile += (p.z()<offset.z);
        int v = xtile + ytile + ztile;
        if (v & 1)
            for (int c = roi.chbegin;  c < roi.chend;  ++c)
                p[c] = color2[c];
        else
            for (int c = roi.chbegin;  c < roi.chend;  ++c)
                p[c] = color1[c];
    }
    return true;
}

static bool
noise_salt_ (ImageBuf &dst, float saltval, float saltportion, bool mono,
             int seed, ROI roi, int nthreads)
{
    if (nthreads != 1 && roi.npixels() >= 1000) {
        // Lots of pixels and request for multi threads? Parallelize.
        ImageBufAlgo::parallel_image (
            OIIO::bind(noise_salt_<T>, OIIO::ref(dst),
                        saltval, saltportion, mono, seed,
                        _1 /*roi*/, 1 /*nthreads*/),
            roi, nthreads);
        return true;
    }

    // Serial case
    for (ImageBuf::Iterator<T> p (dst, roi);  !p.done();  ++p) {
        int x = p.x(), y = p.y(), z = p.z();
        float n = 0.0;
        for (int c = roi.chbegin;  c < roi.chend;  ++c) {
            if (c == roi.chbegin || !mono)
                n = hashrand (x, y, z, c, seed);
            if (n < saltportion)
                p[c] = saltval;
        }
    }
    return true;
}

static bool
noise_gaussian_ (ImageBuf &dst, float mean, float stddev, bool mono,
                 int seed, ROI roi, int nthreads)
{
    if (nthreads != 1 && roi.npixels() >= 1000) {
        // Lots of pixels and request for multi threads? Parallelize.
        ImageBufAlgo::parallel_image (
            OIIO::bind(noise_gaussian_<T>, OIIO::ref(dst),
                        mean, stddev, mono, seed,
                        _1 /*roi*/, 1 /*nthreads*/),
            roi, nthreads);
        return true;
    }

    // Serial case
    for (ImageBuf::Iterator<T> p (dst, roi);  !p.done();  ++p) {
        int x = p.x(), y = p.y(), z = p.z();
        float n = 0.0;
        for (int c = roi.chbegin;  c < roi.chend;  ++c) {
            if (c == roi.chbegin || !mono)
                n = mean + stddev * hashnormal (x, y, z, c, seed);
            p[c] = p[c] + n;
        }
    }
    return true;
}

static bool
flop_ (ImageBuf &dst, const ImageBuf &src, ROI roi, int nthreads)
{
    ImageBuf::ConstIterator<S, D> s (src, roi);
    ImageBuf::Iterator<D, D> d (dst, roi);
    for ( ; ! d.done(); ++d) {
        s.pos (roi.xend-1 - (d.x() - roi.xbegin), d.y(), d.z());
        for (int c = roi.chbegin; c < roi.chend; ++c)
            d[c] = s[c];
    }
    return true;
}

static bool
flip_ (ImageBuf &dst, const ImageBuf &src, ROI dst_roi, int nthreads)
{
    ROI src_roi_full = src.roi_full();
    ROI dst_roi_full = dst.roi_full();
    ImageBuf::ConstIterator<S, D> s (src);
    ImageBuf::Iterator<D, D> d (dst, dst_roi);
    for ( ; ! d.done(); ++d) {
        int yy = d.y() - dst_roi_full.ybegin;
        s.pos (d.x(), src_roi_full.yend-1 - yy, d.z());
        for (int c = dst_roi.chbegin; c < dst_roi.chend; ++c)
            d[c] = s[c];
    }
    return true;
}

bool
ImageBufAlgo::make_kernel (ImageBuf &dst, string_view name,
                           float width, float height, float depth,
                           bool normalize)
{
    int w = std::max (1, (int)ceilf(width));
    int h = std::max (1, (int)ceilf(height));
    int d = std::max (1, (int)ceilf(depth));
    // Round up size to odd
    w |= 1;
    h |= 1;
    d |= 1;
    ImageSpec spec (w, h, 1 /*channels*/, TypeDesc::FLOAT);
    spec.depth = d;
    spec.x = -w/2;
    spec.y = -h/2;
    spec.z = -d/2;
    spec.full_x = spec.x;
    spec.full_y = spec.y;
    spec.full_z = spec.z;
    spec.full_width = spec.width;
    spec.full_height = spec.height;
    spec.full_depth = spec.depth;
    dst.reset (spec);

    if (Filter2D *filter = Filter2D::create (name, width, height)) {
        // Named continuous filter from filter.h
        for (ImageBuf::Iterator<float> p (dst);  ! p.done();  ++p)
            p[0] = (*filter)((float)p.x(), (float)p.y());
        delete filter;
    } else if (name == "binomial") {
        // Binomial filter
        float *wfilter = ALLOCA (float, width);
        for (int i = 0;  i < width;  ++i)
            wfilter[i] = binomial (width-1, i);
        float *hfilter = (height == width) ? wfilter : ALLOCA (float, height);
        if (height != width)
            for (int i = 0;  i < height;  ++i)
                hfilter[i] = binomial (height-1, i);
        float *dfilter = ALLOCA (float, depth);
        if (depth == 1)
            dfilter[0] = 1;
        else
            for (int i = 0;  i < depth;  ++i)
                dfilter[i] = binomial (depth-1, i);
        for (ImageBuf::Iterator<float> p (dst);  ! p.done();  ++p)
            p[0] = wfilter[p.x()-spec.x] * hfilter[p.y()-spec.y] * dfilter[p.z()-spec.z];
    } else {

static bool
convolve_ (ImageBuf &dst, const ImageBuf &src, const ImageBuf &kernel,
           bool normalize, ROI roi, int nthreads)
{
    if (nthreads != 1 && roi.npixels() >= 1000) {
        // Lots of pixels and request for multi threads? Parallelize.
        ImageBufAlgo::parallel_image (
            boost::bind(convolve_<DSTTYPE,SRCTYPE>, boost::ref(dst),
                        boost::cref(src), boost::cref(kernel), normalize,
                        _1 /*roi*/, 1 /*nthreads*/),
            roi, nthreads);
        return true;
    }

    // Serial case

    float scale = 1.0f;
    if (normalize) {
        scale = 0.0f;
        for (ImageBuf::ConstIterator<float> k (kernel); ! k.done(); ++k)
            scale += k[0];
        scale = 1.0f / scale;
    }

    float *sum = ALLOCA (float, roi.chend);
    ROI kroi = get_roi (kernel.spec());
    ImageBuf::Iterator<DSTTYPE> d (dst, roi);
    ImageBuf::ConstIterator<SRCTYPE> s (src, roi, ImageBuf::WrapClamp);
    for ( ; ! d.done();  ++d) {

        for (int c = roi.chbegin; c < roi.chend; ++c)
            sum[c] = 0.0f;

        for (ImageBuf::ConstIterator<float> k (kernel, kroi); !k.done(); ++k) {
            float kval = k[0];
            s.pos (d.x() + k.x(), d.y() + k.y(), d.z() + k.z());
            for (int c = roi.chbegin; c < roi.chend; ++c)
                sum[c] += kval * s[c];
        }
        
        for (int c = roi.chbegin; c < roi.chend; ++c)
            d[c] = scale * sum[c];
    }

    return true;
}

static bool
flatten_ (ImageBuf &dst, const ImageBuf &src, 
          ROI roi, int nthreads)
{
    if (nthreads != 1 && roi.npixels() >= 1000) {
        // Possible multiple thread case -- recurse via parallel_image
        ImageBufAlgo::parallel_image (
            boost::bind(flatten_<DSTTYPE>, boost::ref(dst), boost::cref(src),
                        _1 /*roi*/, 1 /*nthreads*/),
            roi, nthreads);
        return true;
    }

    const ImageSpec &srcspec (src.spec());
    int nc = srcspec.nchannels;

    int alpha_channel, RA_channel, GA_channel, BA_channel;
    int R_channel, G_channel, B_channel;
    int Z_channel, Zback_channel;
    if (! find_deep_channels (srcspec, alpha_channel,
                              RA_channel, GA_channel, BA_channel,
                              R_channel, G_channel, B_channel,
                              Z_channel, Zback_channel)) {
        dst.error ("No alpha channel could be identified");
        return false;
    }
    ASSERT (alpha_channel >= 0 ||
            (RA_channel >= 0 && GA_channel >= 0 && BA_channel >= 0));
    float *val = ALLOCA (float, nc);
    float &RAval (RA_channel >= 0 ? val[RA_channel] : val[alpha_channel]);
    float &GAval (GA_channel >= 0 ? val[GA_channel] : val[alpha_channel]);
    float &BAval (BA_channel >= 0 ? val[BA_channel] : val[alpha_channel]);

    for (ImageBuf::Iterator<DSTTYPE> r (dst, roi);  !r.done();  ++r) {
        int x = r.x(), y = r.y(), z = r.z();
        int samps = src.deep_samples (x, y, z);
        // Clear accumulated values for this pixel (0 for colors, big for Z)
        memset (val, 0, nc*sizeof(float));
        if (Z_channel >= 0 && samps == 0)
            val[Z_channel] = 1.0e30;
        if (Zback_channel >= 0 && samps == 0)
            val[Zback_channel] = 1.0e30;
        for (int s = 0;  s < samps;  ++s) {
            float RA = RAval, GA = GAval, BA = BAval;  // make copies
            float alpha = (RA + GA + BA) / 3.0f;
            if (alpha >= 1.0f)
                break;
            for (int c = 0;  c < nc;  ++c) {
                float v = src.deep_value (x, y, z, c, s);
                if (c == Z_channel || c == Zback_channel)
                    val[c] *= alpha;  // because Z are not premultiplied
                float a;
                if (c == R_channel)
                    a = RA;
                else if (c == G_channel)
                    a = GA;
                else if (c == B_channel)
                    a = BA;
                else
                    a = alpha;
                val[c] += (1.0f - a) * v;
            }
        }

        for (int c = roi.chbegin;  c < roi.chend;  ++c)
            r[c] = val[c];
    }

    return true;
}