text: /*
      This file is part of Mitsuba, a physically based rendering system.
  
      Copyright (c) 2007-2014 by Wenzel Jakob and others.
  
      Mitsuba is free software; you can redistribute it and/or modify
      it under the terms of the GNU General Public License Version 3
      as published by the Free Software Foundation.
  
      Mitsuba is distributed in the hope that it will be useful,
      but WITHOUT ANY WARRANTY; without even the implied warranty of
      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
      GNU General Public License for more details.
  
      You should have received a copy of the GNU General Public License
      along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
  
  #include <mitsuba/render/film.h>
  #include <mitsuba/core/fstream.h>
  #include <mitsuba/core/bitmap.h>
  #include <mitsuba/core/statistics.h>
  #include <boost/algorithm/string.hpp>
  #include "banner.h"
  #include "annotations.h"
  
  MTS_NAMESPACE_BEGIN
  
  /*!\plugin{hdrfilm}{High dynamic range film}
   * \order{1}
   * \parameters{
   *     \parameter{width, height}{\Integer}{
   *       Width and height of the camera sensor in pixels
   *       \default{768, 576}
   *     }
   *     \parameter{fileFormat}{\String}{
   *       Denotes the desired output file format. The options
   *       are \code{openexr} (for ILM's OpenEXR format),
   *       \code{rgbe} (for Greg Ward's RGBE format),
   *       or \code{pfm} (for the Portable Float Map format)
   *       \default{\code{openexr}}
   *     }
   *     \parameter{pixelFormat}{\String}{Specifies the desired pixel format
   *         of output images. The options are \code{luminance},
   *         \code{luminanceAlpha}, \code{rgb}, \code{rgba}, \code{xyz},
   *         \code{xyza}, \code{spectrum}, and \code{spectrumAlpha}.
   *         For the \code{spectrum*} options, the number of written channels depends on
   *         the value assigned to \code{SPECTRUM\_SAMPLES} during compilation
   *         (see \secref{compiling} for details)
   *         \default{\code{rgb}}
   *     }
   *     \parameter{componentFormat}{\String}{Specifies the desired floating
   *         point component format of output images. The options are
   *         \code{float16}, \code{float32}, or \code{uint32}.
   *         \default{\code{float16}}
   *     }
   *     \parameter{cropOffsetX, cropOffsetY, cropWidth, cropHeight}{\Integer}{
   *       These parameters can optionally be provided to select a sub-rectangle
   *       of the output. In this case, Mitsuba will only render the requested
   *       regions. \default{Unused}
   *     }
   *     \parameter{attachLog}{\Boolean}{Mitsuba can optionally attach
   *         the entire rendering log file as a metadata field so that this
   *         information is permanently saved.
   *         \default{\code{true}, i.e. attach it}
   *     }
   *     \parameter{banner}{\Boolean}{Include a small Mitsuba banner in the
   *         output image? \default{\code{true}}
   *     }
   *     \parameter{highQualityEdges}{\Boolean}{
   *        If set to \code{true}, regions slightly outside of the film
   *        plane will also be sampled. This may improve the image
   *        quality at the edges, especially when using very large
   *        reconstruction filters. In general, this is not needed though.
   *        \default{\code{false}, i.e. disabled}
   *     }
   *     \parameter{\Unnamed}{\RFilter}{Reconstruction filter that should
   *     be used by the film. \default{\code{gaussian}, a windowed Gaussian filter}}
   * }
   *
   * This is the default film plugin that is used when none is explicitly
   * specified. It stores the captured image as a high dynamic range OpenEXR file
   * and tries to preserve the rendering as much as possible by not performing any
   * kind of post processing, such as gamma correction---the output file
   * will record linear radiance values.
   *
   * When writing OpenEXR files, the film will either produce a luminance, luminance/alpha,
   * RGB(A), XYZ(A) tristimulus, or spectrum/spectrum-alpha-based bitmap having a
   * \code{float16}, \code{float32}, or \code{uint32}-based internal representation
   * based on the chosen parameters.
   * The default configuration is RGB with a \code{float16} component format,
   * which is appropriate for most purposes. Note that the spectral output options
   * only make sense when using a custom build of Mitsuba that has spectral
   * rendering enabled (this is not the case for the downloadable release builds).
   * For OpenEXR files, Mitsuba also supports fully general multi-channel output;
   * refer to the \pluginref{multichannel} plugin for details on how this works.
   *
   * The plugin can also write RLE-compressed files in the Radiance RGBE format
   * pioneered by Greg Ward (set \code{fileFormat=rgbe}), as well as the
   * Portable Float Map format (set \code{fileFormat=pfm}).
   * In the former case,
   * the \code{componentFormat} and \code{pixelFormat} parameters are ignored,
   * and the output is ``\code{float8}''-compressed RGB data.
   * PFM output is restricted to \code{float32}-valued images using the
   * \code{rgb} or \code{luminance} pixel formats.
   * Due to the superior accuracy and adoption of OpenEXR, the use of these
   * two alternative formats is discouraged however.
   *
   * When RGB(A) output is selected, the measured spectral power distributions are
   * converted to linear RGB based on the CIE 1931 XYZ color matching curves and
   * the ITU-R Rec. BT.709-3 primaries with a D65 white point.
   *
   * \begin{xml}[caption=Instantiation of a film that writes a full-HD RGBA OpenEXR file without the Mitsuba banner]
   * <film type="hdrfilm">
   *     <string name="pixelFormat" value="rgba"/>
   *     <integer name="width" value="1920"/>
   *     <integer name="height" value="1080"/>
   *     <boolean name="banner" value="false"/>
   * </film>
   * \end{xml}
   *
   * \subsubsection*{Render-time annotations:}
   * \label{sec:film-annotations}
   * The \pluginref{ldrfilm} and \pluginref{hdrfilm} plugins support a
   * feature referred to as \emph{render-time annotations} to facilitate
   * record keeping.
   * Annotations are used to embed useful information inside a rendered image so
   * that this information is later available to anyone viewing the image.
   * Exemplary uses of this feature might be to store the frame or take number,
   * rendering time, memory usage, camera parameters, or other relevant scene
   * information.
   *
   * Currently, two different types are supported: a \code{metadata} annotation
   * creates an entry in the metadata table of the image, which is preferable
   * when the image contents should not be touched. Alternatively, a \code{label}
   * annotation creates a line of text that is overlaid on top of the image. Note
   * that this is only visible when opening the output file (i.e. the line is not
   * shown in the interactive viewer).
   * The syntax of this looks as follows:
   *
   * \begin{xml}
   * <film type="hdrfilm">
   *  <!-- Create a new metadata entry 'my_tag_name' and set it to the
   *       value 'my_tag_value' -->
   *  <string name="metadata['key_name']" value="Hello!"/>
   *
   *  <!-- Add the label 'Hello' at the image position X=50, Y=80 -->
   *  <string name="label[50, 80]" value="Hello!"/>
   * </film>
   * \end{xml}
   *
   * The \code{value="..."} argument may also include certain keywords that will be
   * evaluated and substituted when the rendered image is written to disk. A list all available
   * keywords is provided in Table~\ref{tbl:film-keywords}.
   *
   * Apart from querying the render time,
   * memory usage, and other scene-related information, it is also possible
   * to `paste' an existing parameter that was provided to another plugin---for instance,
   * the camera transform matrix would be obtained as \code{\$sensor['toWorld']}. The name of
   * the active integrator plugin is given by \code{\$integrator['type']}, and so on.
   * All of these can be mixed to build larger fragments, as following example demonstrates.
   * The result of this annotation is shown in Figure~\ref{fig:annotation-example}.
   * \begin{xml}[mathescape=false]
   * <string name="label[10, 10]" value="Integrator: $integrator['type'],
   *   $film['width']x$film['height'], $sampler['sampleCount'] spp,
   *   render time: $scene['renderTime'], memory: $scene['memUsage']"/>
   * \end{xml}
   * \vspace{1cm}
   * \renderings{
   * \fbox{\includegraphics[width=.8\textwidth]{images/annotation_example}}\hfill\,
   * \caption{\label{fig:annotation-example}A demonstration of the label annotation feature
   *  given the example string shown above.}
   * }
   * \vspace{2cm}
   * \begin{table}[htb]
   * \centering
   * \begin{savenotes}
   * \begin{tabular}{ll}
   * \toprule
   * \code{\$scene['renderTime']}& Image render time, use \code{renderTimePrecise} for more digits.\\
   * \code{\$scene['memUsage']}& Mitsuba memory usage\footnote{The definition of this quantity unfortunately
   * varies a bit from platform to platform. On Linux and Windows, it denotes the total
   * amount of allocated RAM and disk-based memory that is private to the process (i.e. not
   * shared or shareable), which most intuitively captures the amount of memory required for
   * rendering. On OSX, it denotes the working set size---roughly speaking, this is the
   * amount of RAM apportioned to the process (i.e. excluding disk-based memory).}.
   * Use \code{memUsagePrecise} for more digits.\\
   * \code{\$scene['coreCount']}& Number of local and remote cores working on the rendering job\\
   * \code{\$scene['blockSize']}& Block size used to parallelize up the rendering workload\\
   * \code{\$scene['sourceFile']}& Source file name\\
   * \code{\$scene['destFile']}& Destination file name\\
   * \code{\$integrator['..']}& Copy a named integrator parameter\\
   * \code{\$sensor['..']}& Copy a named sensor parameter\\
   * \code{\$sampler['..']}& Copy a named sampler parameter\\
   * \code{\$film['..']}& Copy a named film parameter\\
   * \bottomrule
   * \end{tabular}
   * \end{savenotes}
   * \caption{\label{tbl:film-keywords}A list of all special
   * keywords supported by the annotation feature}
   * \end{table}
   *
   */
  
  class HDRFilm : public Film {
  public:
      HDRFilm(const Properties &props) : Film(props) {
          /* Should an Mitsuba banner be added to the output image? */
          m_banner = props.getBoolean("banner", true);
          /* Attach the log file as the EXR comment attribute? */
          m_attachLog = props.getBoolean("attachLog", true);
  
          std::string fileFormat = boost::to_lower_copy(
              props.getString("fileFormat", "openexr"));
          std::vector<std::string> pixelFormats = tokenize(boost::to_lower_copy(
              props.getString("pixelFormat", "rgb")), " ,");
          std::vector<std::string> channelNames = tokenize(
              props.getString("channelNames", ""), ", ");
          std::string componentFormat = boost::to_lower_copy(
              props.getString("componentFormat", "float16"));
  
          if (fileFormat == "openexr") {
              m_fileFormat = Bitmap::EOpenEXR;
          } else if (fileFormat == "rgbe") {
              m_fileFormat = Bitmap::ERGBE;
          } else if (fileFormat == "pfm") {
              m_fileFormat = Bitmap::EPFM;
          } else {
              Log(EError, "The \"fileFormat\" parameter must either be "
                  "equal to \"openexr\", \"pfm\", or \"rgbe\"!");
          }
  
          if (pixelFormats.empty())
              Log(EError, "At least one pixel format must be specified!");
  
          if ((pixelFormats.size() != 1 && channelNames.size() != pixelFormats.size()) ||
              (pixelFormats.size() == 1 && channelNames.size() > 1))
              Log(EError, "Number of channel names must match the number of specified pixel formats!");
  
          if (pixelFormats.size() != 1 && m_fileFormat != Bitmap::EOpenEXR)
              Log(EError, "General multi-channel output is only supported when writing OpenEXR files!");
  
          for (size_t i=0; i<pixelFormats.size(); ++i) {
              std::string pixelFormat = pixelFormats[i];
              std::string name = i < channelNames.size() ? (channelNames[i] + std::string(".")) : "";
  
              if (pixelFormat == "luminance") {
                  m_pixelFormats.push_back(Bitmap::ELuminance);
                  m_channelNames.push_back(name + "Y");
              } else if (pixelFormat == "luminancealpha") {
                  m_pixelFormats.push_back(Bitmap::ELuminanceAlpha);
                  m_channelNames.push_back(name + "Y");
                  m_channelNames.push_back(name + "A");
              } else if (pixelFormat == "rgb") {
                  m_pixelFormats.push_back(Bitmap::ERGB);
                  m_channelNames.push_back(name + "R");
                  m_channelNames.push_back(name + "G");
                  m_channelNames.push_back(name + "B");
              } else if (pixelFormat == "rgba") {
                  m_pixelFormats.push_back(Bitmap::ERGBA);
                  m_channelNames.push_back(name + "R");
                  m_channelNames.push_back(name + "G");
                  m_channelNames.push_back(name + "B");
                  m_channelNames.push_back(name + "A");
              } else if (pixelFormat == "xyz") {
                  m_pixelFormats.push_back(Bitmap::EXYZ);
                  m_channelNames.push_back(name + "X");
                  m_channelNames.push_back(name + "Y");
                  m_channelNames.push_back(name + "Z");
              } else if (pixelFormat == "xyza") {
                  m_pixelFormats.push_back(Bitmap::EXYZA);
                  m_channelNames.push_back(name + "X");
                  m_channelNames.push_back(name + "Y");
                  m_channelNames.push_back(name + "Z");
                  m_channelNames.push_back(name + "A");
              } else if (pixelFormat == "spectrum") {
                  m_pixelFormats.push_back(Bitmap::ESpectrum);
                  for (int i=0; i<SPECTRUM_SAMPLES; ++i) {
                      std::pair<Float, Float> coverage = Spectrum::getBinCoverage(i);
                      m_channelNames.push_back(name + formatString("%.2f-%.2fnm", coverage.first, coverage.second));
                  }
              } else if (pixelFormat == "spectrumalpha") {
                  m_pixelFormats.push_back(Bitmap::ESpectrumAlpha);
                  for (int i=0; i<SPECTRUM_SAMPLES; ++i) {
                      std::pair<Float, Float> coverage = Spectrum::getBinCoverage(i);
                      m_channelNames.push_back(name + formatString("%.2f-%.2fnm", coverage.first, coverage.second));
                  }
                  m_channelNames.push_back(name + "A");
              } else {
                  Log(EError, "The \"pixelFormat\" parameter must either be equal to "
                      "\"luminance\", \"luminanceAlpha\", \"rgb\", \"rgba\", \"xyz\", \"xyza\", "
                      "\"spectrum\", or \"spectrumAlpha\"!");
              }
          }
  
          for (size_t i=0; i<m_pixelFormats.size(); ++i) {
              if (SPECTRUM_SAMPLES == 3 && (m_pixelFormats[i] == Bitmap::ESpectrum || m_pixelFormats[i] == Bitmap::ESpectrumAlpha))
                  Log(EError, "You requested to render a spectral image, but Mitsuba is currently "
                      "configured for a RGB flow (i.e. SPECTRUM_SAMPLES = 3). You will need to recompile "
                      "it with a different configuration. Please see the documentation for details.");
          }
  
          if (componentFormat == "float16") {
              m_componentFormat = Bitmap::EFloat16;
          } else if (componentFormat == "float32") {
              m_componentFormat = Bitmap::EFloat32;
          } else if (componentFormat == "uint32") {
              m_componentFormat = Bitmap::EUInt32;
          } else {
              Log(EError, "The \"componentFormat\" parameter must either be "
                  "equal to \"float16\", \"float32\", or \"uint32\"!");
          }
  
          if (m_fileFormat == Bitmap::ERGBE) {
              /* RGBE output; override pixel & component format if necessary */
              if (m_pixelFormats.size() != 1)
                  Log(EError, "The RGBE format does not support general multi-channel images!");
              if (m_pixelFormats[0] != Bitmap::ERGB) {
                  Log(EWarn, "The RGBE format only supports pixelFormat=\"rgb\". Overriding..");
                  m_pixelFormats[0] = Bitmap::ERGB;
              }
              if (m_componentFormat != Bitmap::EFloat32) {
                  Log(EWarn, "The RGBE format only supports componentFormat=\"float32\". Overriding..");
                  m_componentFormat = Bitmap::EFloat32;
              }
          } else if (m_fileFormat == Bitmap::EPFM) {
              /* PFM output; override pixel & component format if necessary */
              if (m_pixelFormats.size() != 1)
                  Log(EError, "The PFM format does not support general multi-channel images!");
              if (m_pixelFormats[0] != Bitmap::ERGB && m_pixelFormats[0] != Bitmap::ELuminance) {
                  Log(EWarn, "The PFM format only supports pixelFormat=\"rgb\" or \"luminance\"."
                      " Overriding (setting to \"rgb\")..");
                  m_pixelFormats[0] = Bitmap::ERGB;
              }
              if (m_componentFormat != Bitmap::EFloat32) {
                  Log(EWarn, "The PFM format only supports componentFormat=\"float32\". Overriding..");
                  m_componentFormat = Bitmap::EFloat32;
              }
          }
  
          std::vector<std::string> keys = props.getPropertyNames();
          for (size_t i=0; i<keys.size(); ++i) {
              std::string key = boost::to_lower_copy(keys[i]);
              key.erase(std::remove_if(key.begin(), key.end(), ::isspace), key.end());
  
              if ((boost::starts_with(key, "metadata['") && boost::ends_with(key, "']")) ||
                  (boost::starts_with(key, "label[") && boost::ends_with(key, "]")))
                  props.markQueried(keys[i]);
          }
  
          if (m_pixelFormats.size() == 1) {
              m_storage = new ImageBlock(Bitmap::ESpectrumAlphaWeight, m_cropSize);
          } else {
              m_storage = new ImageBlock(Bitmap::EMultiSpectrumAlphaWeight, m_cropSize,
                  NULL, (int) (SPECTRUM_SAMPLES * m_pixelFormats.size() + 2));
          }
      }
  
      HDRFilm(Stream *stream, InstanceManager *manager)
          : Film(stream, manager) {
          m_banner = stream->readBool();
          m_attachLog = stream->readBool();
          m_fileFormat = (Bitmap::EFileFormat) stream->readUInt();
          m_pixelFormats.resize((size_t) stream->readUInt());
          for (size_t i=0; i<m_pixelFormats.size(); ++i)
              m_pixelFormats[i] = (Bitmap::EPixelFormat) stream->readUInt();
          m_channelNames.resize((size_t) stream->readUInt());
          for (size_t i=0; i<m_channelNames.size(); ++i)
              m_channelNames[i] = stream->readString();
          m_componentFormat = (Bitmap::EComponentFormat) stream->readUInt();
      }
  
      void serialize(Stream *stream, InstanceManager *manager) const {
          Film::serialize(stream, manager);
          stream->writeBool(m_banner);
          stream->writeBool(m_attachLog);
          stream->writeUInt(m_fileFormat);
          stream->writeUInt((uint32_t) m_pixelFormats.size());
          for (size_t i=0; i<m_pixelFormats.size(); ++i)
              stream->writeUInt(m_pixelFormats[i]);
          stream->writeUInt((uint32_t) m_channelNames.size());
          for (size_t i=0; i<m_channelNames.size(); ++i)
              stream->writeString(m_channelNames[i]);
          stream->writeUInt(m_componentFormat);
      }
  
      void clear() {
          m_storage->clear();
      }
  
      void put(const ImageBlock *block) {
          m_storage->put(block);
      }
  
      void setBitmap(const Bitmap *bitmap, Float multiplier) {
          bitmap->convert(m_storage->getBitmap(), multiplier);
      }
  
      void addBitmap(const Bitmap *bitmap, Float multiplier) {
          /* Currently, only accumulating spectrum-valued floating point images
             is supported. This function basically just exists to support the
             somewhat peculiar film updates done by BDPT */
  
          Vector2i size = bitmap->getSize();
          if (bitmap->getPixelFormat() != Bitmap::ESpectrum ||
              bitmap->getComponentFormat() != Bitmap::EFloat ||
              bitmap->getGamma() != 1.0f ||
              size != m_storage->getSize() ||
              m_pixelFormats.size() != 1) {
              Log(EError, "addBitmap(): Unsupported bitmap format!");
          }
  
          size_t nPixels = (size_t) size.x * (size_t) size.y;
          const Float *source = bitmap->getFloatData();
          Float *target = m_storage->getBitmap()->getFloatData();
          for (size_t i=0; i<nPixels; ++i) {
              Float weight = target[SPECTRUM_SAMPLES + 1];
              if (weight == 0)
                  weight = target[SPECTRUM_SAMPLES + 1] = 1;
              weight *= multiplier;
              for (size_t j=0; j<SPECTRUM_SAMPLES; ++j)
                  *target++ += *source++ * weight;
              target += 2;
          }
      }
  
      bool develop(const Point2i &sourceOffset, const Vector2i &size,
              const Point2i &targetOffset, Bitmap *target) const {
          const Bitmap *source = m_storage->getBitmap();
          const FormatConverter *cvt = FormatConverter::getInstance(
              std::make_pair(Bitmap::EFloat, target->getComponentFormat())
          );
  
          size_t sourceBpp = source->getBytesPerPixel();
          size_t targetBpp = target->getBytesPerPixel();
  
          const uint8_t *sourceData = source->getUInt8Data()
              + (sourceOffset.x + sourceOffset.y * source->getWidth()) * sourceBpp;
          uint8_t *targetData = target->getUInt8Data()
              + (targetOffset.x + targetOffset.y * target->getWidth()) * targetBpp;
  
          if (EXPECT_NOT_TAKEN(m_pixelFormats.size() != 1)) {
              /* Special case for general multi-channel images -- just develop the first component(s) */
              for (int i=0; i<size.y; ++i) {
                  for (int j=0; j<size.x; ++j) {
                      Float weight = *((Float *) (sourceData + (j+1)*sourceBpp - sizeof(Float)));
                      Float invWeight = weight != 0 ? ((Float) 1 / weight) : (Float) 0;
                      cvt->convert(Bitmap::ESpectrum, 1.0f, sourceData + j*sourceBpp,
                          target->getPixelFormat(), target->getGamma(), targetData + j * targetBpp,
                          1, invWeight);
                  }
  
                  sourceData += source->getWidth() * sourceBpp;
                  targetData += target->getWidth() * targetBpp;
              }
  
          } else if (size.x == m_cropSize.x && target->getWidth() == m_storage->getWidth()) {
              /* Develop a connected part of the underlying buffer */
              cvt->convert(source->getPixelFormat(), 1.0f, sourceData,
                  target->getPixelFormat(), target->getGamma(), targetData,
                  size.x*size.y);
          } else {
              /* Develop a rectangular subregion */
              for (int i=0; i<size.y; ++i) {
                  cvt->convert(source->getPixelFormat(), 1.0f, sourceData,
                      target->getPixelFormat(), target->getGamma(), targetData,
                      size.x);
  
                  sourceData += source->getWidth() * sourceBpp;
                  targetData += target->getWidth() * targetBpp;
              }
          }
  
          return true;
      }
  
      void setDestinationFile(const fs::path &destFile, uint32_t blockSize) {
          m_destFile = destFile;
      }
  
      void develop(const Scene *scene, Float renderTime) {
          if (m_destFile.empty())
              return;
  
          Log(EDebug, "Developing film ..");
  
          ref<Bitmap> bitmap;
          if (m_pixelFormats.size() == 1) {
              bitmap = m_storage->getBitmap()->convert(m_pixelFormats[0], m_componentFormat);
              bitmap->setChannelNames(m_channelNames);
          } else {
              bitmap = m_storage->getBitmap()->convertMultiSpectrumAlphaWeight(m_pixelFormats,
                      m_componentFormat, m_channelNames);
          }
  
          if (m_banner && m_cropSize.x > bannerWidth+5 && m_cropSize.y > bannerHeight + 5 && m_pixelFormats.size() == 1) {
              int xoffs = m_cropSize.x - bannerWidth - 5,
                  yoffs = m_cropSize.y - bannerHeight - 5;
              for (int y=0; y<bannerHeight; y++) {
                  for (int x=0; x<bannerWidth; x++) {
                      if (banner[x+y*bannerWidth])
                          continue;
                      bitmap->setPixel(Point2i(x+xoffs, y+yoffs), Spectrum(1024));
                  }
              }
          }
  
          fs::path filename = m_destFile;
          std::string properExtension;
          if (m_fileFormat == Bitmap::EOpenEXR)
              properExtension = ".exr";
          else if (m_fileFormat == Bitmap::ERGBE)
              properExtension = ".rgbe";
          else
              properExtension = ".pfm";
  
          std::string extension = boost::to_lower_copy(filename.extension().string());
          if (extension != properExtension)
              filename.replace_extension(properExtension);
  
          Log(EInfo, "Writing image to \"%s\" ..", filename.string().c_str());
          ref<FileStream> stream = new FileStream(filename, FileStream::ETruncWrite);
  
          if (m_pixelFormats.size() == 1)
              annotate(scene, m_properties, bitmap, renderTime, 1.0f);
  
          /* Attach the log file to the image if this is requested */
          Logger *logger = Thread::getThread()->getLogger();
          std::string log;
          if (m_attachLog && logger->readLog(log)) {
              log += "\n\n";
              log += Statistics::getInstance()->getStats();
              bitmap->setMetadataString("log", log);
          }
  
          bitmap->write(m_fileFormat, stream);
      }
  
      bool hasAlpha() const {
          for (size_t i=0; i<m_pixelFormats.size(); ++i) {
              if (m_pixelFormats[i] == Bitmap::ELuminanceAlpha ||
                  m_pixelFormats[i] == Bitmap::ERGBA ||
                  m_pixelFormats[i] == Bitmap::EXYZA ||
                  m_pixelFormats[i] == Bitmap::ESpectrumAlpha)
                  return true;
          }
          return false;
      }
  
      bool destinationExists(const fs::path &baseName) const {
          std::string properExtension;
          if (m_fileFormat == Bitmap::EOpenEXR)
              properExtension = ".exr";
          else if (m_fileFormat == Bitmap::ERGBE)
              properExtension = ".rgbe";
          else
              properExtension = ".pfm";
  
          fs::path filename = baseName;
          if (boost::to_lower_copy(filename.extension().string()) != properExtension)
              filename.replace_extension(properExtension);
          return fs::exists(filename);
      }
  
      std::string toString() const {
          std::ostringstream oss;
          oss << "HDRFilm[" << endl
              << "  size = " << m_size.toString() << "," << endl
              << "  fileFormat = " << m_fileFormat << "," << endl
              << "  pixelFormat = ";
          for (size_t i=0; i<m_pixelFormats.size(); ++i)
              oss << m_pixelFormats[i] << ", ";
          oss << endl
              << "  channelNames = ";
          for (size_t i=0; i<m_channelNames.size(); ++i)
              oss << "\"" << m_channelNames[i] << "\"" << ", ";
          oss << endl
              << "  componentFormat = " << m_componentFormat << "," << endl
              << "  cropOffset = " << m_cropOffset.toString() << "," << endl
              << "  cropSize = " << m_cropSize.toString() << "," << endl
              << "  banner = " << m_banner << "," << endl
              << "  filter = " << indent(m_filter->toString()) << endl
              << "]";
          return oss.str();
      }
  
      MTS_DECLARE_CLASS()
  protected:
      Bitmap::EFileFormat m_fileFormat;
      std::vector<Bitmap::EPixelFormat> m_pixelFormats;
      std::vector<std::string> m_channelNames;
      Bitmap::EComponentFormat m_componentFormat;
      bool m_banner;
      bool m_attachLog;
      fs::path m_destFile;
      ref<ImageBlock> m_storage;
  };
  
  MTS_IMPLEMENT_CLASS_S(HDRFilm, false, Film)
  MTS_EXPORT_PLUGIN(HDRFilm, "High dynamic range film");
  MTS_NAMESPACE_END
  