mfilm.cpp: support for writing NumPy files (submitted by Joe Kider)

src/films/SConscript

@@ -10,7 +10,7 @@ if filmEnv.has_key('OEXRFLAGS'):
 if filmEnv.has_key('OEXRLIB'):
 	filmEnv.Prepend(LIBS=env['OEXRLIB'])
 
-plugins += filmEnv.SharedLibrary('mfilm', ['mfilm.cpp'])
+plugins += filmEnv.SharedLibrary('mfilm', ['mfilm.cpp', 'cnpy.cpp'])
 plugins += filmEnv.SharedLibrary('ldrfilm', ['ldrfilm.cpp'])
 plugins += filmEnv.SharedLibrary('hdrfilm', ['hdrfilm.cpp'])
 

src/films/cnpy.cpp

@@ -0,0 +1,246 @@
+//Copyright (C) 2011  Carl Rogers
+//Released under MIT License
+//license available in LICENSE file, or at http://www.opensource.org/licenses/mit-license.php
+
+#include"cnpy.h"
+#include<complex>
+#include<cstdlib>
+#include<algorithm>
+#include<cstring>
+#include<iomanip>
+
+char cnpy::BigEndianTest() {
+    unsigned char x[] = {1,0};
+    short y = *(short*) x;
+    return y == 1 ? '<' : '>';
+}
+
+char cnpy::map_type(const std::type_info& t)
+{
+    if(t == typeid(float) ) return 'f';
+    if(t == typeid(double) ) return 'f';
+    if(t == typeid(long double) ) return 'f';
+
+    if(t == typeid(int) ) return 'i';
+    if(t == typeid(char) ) return 'i';
+    if(t == typeid(short) ) return 'i';
+    if(t == typeid(long) ) return 'i';
+    if(t == typeid(long long) ) return 'i';
+
+    if(t == typeid(unsigned char) ) return 'u';
+    if(t == typeid(unsigned short) ) return 'u';
+    if(t == typeid(unsigned long) ) return 'u';
+    if(t == typeid(unsigned long long) ) return 'u';
+    if(t == typeid(unsigned int) ) return 'u';
+
+    if(t == typeid(bool) ) return 'b';
+
+    if(t == typeid(std::complex<float>) ) return 'c';
+    if(t == typeid(std::complex<double>) ) return 'c';
+    if(t == typeid(std::complex<long double>) ) return 'c';
+
+    else return '?';
+}
+
+template<> std::vector<char>& cnpy::operator+=(std::vector<char>& lhs, const std::string rhs) {
+    lhs.insert(lhs.end(),rhs.begin(),rhs.end());
+    return lhs;
+}
+
+template<> std::vector<char>& cnpy::operator+=(std::vector<char>& lhs, const char* rhs) {
+    //write in little endian
+    size_t len = strlen(rhs);
+    lhs.reserve(len);
+    for(size_t byte = 0; byte < len; byte++) {
+        lhs.push_back(rhs[byte]);
+    }
+    return lhs;
+}
+
+void cnpy::parse_npy_header(FILE* fp, unsigned int& word_size, unsigned int*& shape, unsigned int& ndims, bool& fortran_order) {
+    char buffer[256];
+    size_t res = fread(buffer,sizeof(char),11,fp);
+    if(res != 11)
+        throw std::runtime_error("parse_npy_header: failed fread");
+    std::string header = fgets(buffer,256,fp);
+    assert(header[header.size()-1] == '\n');
+
+    int loc1, loc2;
+
+    //fortran order
+    loc1 = header.find("fortran_order")+16;
+    fortran_order = (header.substr(loc1,5) == "True" ? true : false);
+
+    //shape
+    loc1 = header.find("(");
+    loc2 = header.find(")");
+    std::string str_shape = header.substr(loc1+1,loc2-loc1-1);
+    if(str_shape[str_shape.size()-1] == ',') ndims = 1;
+    else ndims = std::count(str_shape.begin(),str_shape.end(),',')+1;
+    shape = new unsigned int[ndims];
+    for(unsigned int i = 0;i < ndims;i++) {
+        loc1 = str_shape.find(",");
+        shape[i] = atoi(str_shape.substr(0,loc1).c_str());
+        str_shape = str_shape.substr(loc1+1);
+    }
+
+    //endian, word size, data type
+    //byte order code | stands for not applicable.
+    //not sure when this applies except for byte array
+    loc1 = header.find("descr")+9;
+    bool littleEndian = (header[loc1] == '<' || header[loc1] == '|' ? true : false);
+    assert(littleEndian);
+
+    //char type = header[loc1+1];
+    //assert(type == map_type(T));
+
+    std::string str_ws = header.substr(loc1+2);
+    loc2 = str_ws.find("'");
+    word_size = atoi(str_ws.substr(0,loc2).c_str());
+}
+
+void cnpy::parse_zip_footer(FILE* fp, unsigned short& nrecs, unsigned int& global_header_size, unsigned int& global_header_offset)
+{
+    std::vector<char> footer(22);
+    fseek(fp,-22,SEEK_END);
+    size_t res = fread(&footer[0],sizeof(char),22,fp);
+    if(res != 22)
+        throw std::runtime_error("parse_zip_footer: failed fread");
+
+    unsigned short disk_no, disk_start, nrecs_on_disk, comment_len;
+    disk_no = *(unsigned short*) &footer[4];
+    disk_start = *(unsigned short*) &footer[6];
+    nrecs_on_disk = *(unsigned short*) &footer[8];
+    nrecs = *(unsigned short*) &footer[10];
+    global_header_size = *(unsigned int*) &footer[12];
+    global_header_offset = *(unsigned int*) &footer[16];
+    comment_len = *(unsigned short*) &footer[20];
+
+    assert(disk_no == 0);
+    assert(disk_start == 0);
+    assert(nrecs_on_disk == nrecs);
+    assert(comment_len == 0);
+}
+
+cnpy::NpyArray load_the_npy_file(FILE* fp) {
+    unsigned int* shape;
+    unsigned int ndims, word_size;
+    bool fortran_order;
+    cnpy::parse_npy_header(fp,word_size,shape,ndims,fortran_order);
+    unsigned long long size = 1; //long long so no overflow when multiplying by word_size
+    for(unsigned int i = 0;i < ndims;i++) size *= shape[i];
+
+    cnpy::NpyArray arr;
+    arr.word_size = word_size;
+    arr.shape = std::vector<unsigned int>(shape,shape+ndims);
+    arr.data = new char[size*word_size];
+    arr.fortran_order = fortran_order;
+    size_t nread = fread(arr.data,word_size,size,fp);
+    if(nread != size)
+        throw std::runtime_error("load_the_npy_file: failed fread");
+    return arr;
+}
+
+cnpy::npz_t cnpy::npz_load(std::string fname) {
+    FILE* fp = fopen(fname.c_str(),"rb");
+
+    if(!fp) printf("npz_load: Error! Unable to open file %s!\n",fname.c_str());
+    assert(fp);
+
+    cnpy::npz_t arrays;
+
+    while(1) {
+        std::vector<char> local_header(30);
+        size_t headerres = fread(&local_header[0],sizeof(char),30,fp);
+        if(headerres != 30)
+            throw std::runtime_error("npz_load: failed fread");
+
+        //if we've reached the global header, stop reading
+        if(local_header[2] != 0x03 || local_header[3] != 0x04) break;
+
+        //read in the variable name
+        unsigned short name_len = *(unsigned short*) &local_header[26];
+        std::string varname(name_len,' ');
+        size_t vname_res = fread(&varname[0],sizeof(char),name_len,fp);
+        if(vname_res != name_len)
+            throw std::runtime_error("npz_load: failed fread");
+
+        //erase the lagging .npy
+        varname.erase(varname.end()-4,varname.end());
+
+        //read in the extra field
+        unsigned short extra_field_len = *(unsigned short*) &local_header[28];
+        if(extra_field_len > 0) {
+            std::vector<char> buff(extra_field_len);
+            size_t efield_res = fread(&buff[0],sizeof(char),extra_field_len,fp);
+            if(efield_res != extra_field_len)
+                throw std::runtime_error("npz_load: failed fread");
+        }
+
+        arrays[varname] = load_the_npy_file(fp);
+    }
+
+    fclose(fp);
+    return arrays;
+}
+
+cnpy::NpyArray cnpy::npz_load(std::string fname, std::string varname) {
+    FILE* fp = fopen(fname.c_str(),"rb");
+
+    if(!fp) {
+        printf("npz_load: Error! Unable to open file %s!\n",fname.c_str());
+        abort();
+    }
+
+    while(1) {
+        std::vector<char> local_header(30);
+        size_t header_res = fread(&local_header[0],sizeof(char),30,fp);
+        if(header_res != 30)
+            throw std::runtime_error("npz_load: failed fread");
+
+        //if we've reached the global header, stop reading
+        if(local_header[2] != 0x03 || local_header[3] != 0x04) break;
+
+        //read in the variable name
+        unsigned short name_len = *(unsigned short*) &local_header[26];
+        std::string vname(name_len,' ');
+        size_t vname_res = fread(&vname[0],sizeof(char),name_len,fp);
+        if(vname_res != name_len)
+            throw std::runtime_error("npz_load: failed fread");
+        vname.erase(vname.end()-4,vname.end()); //erase the lagging .npy
+
+        //read in the extra field
+        unsigned short extra_field_len = *(unsigned short*) &local_header[28];
+        fseek(fp,extra_field_len,SEEK_CUR); //skip past the extra field
+
+        if(vname == varname) {
+            NpyArray array = load_the_npy_file(fp);
+            fclose(fp);
+            return array;
+        }
+        else {
+            //skip past the data
+            unsigned int size = *(unsigned int*) &local_header[22];
+            fseek(fp,size,SEEK_CUR);
+        }
+    }
+
+    fclose(fp);
+    printf("npz_load: Error! Variable name %s not found in %s!\n",varname.c_str(),fname.c_str());
+    abort();
+}
+
+cnpy::NpyArray cnpy::npy_load(std::string fname) {
+
+    FILE* fp = fopen(fname.c_str(), "rb");
+
+    if(!fp) {
+        printf("npy_load: Error! Unable to open file %s!\n",fname.c_str());
+        abort();
+    }
+
+    NpyArray arr = load_the_npy_file(fp);
+
+    fclose(fp);
+    return arr;
+}

src/films/cnpy.h

@@ -0,0 +1,241 @@
+//Copyright (C) 2011  Carl Rogers
+//Released under MIT License
+//license available in LICENSE file, or at http://www.opensource.org/licenses/mit-license.php
+
+#ifndef LIBCNPY_H_
+#define LIBCNPY_H_
+
+#include<string>
+#include<stdexcept>
+#include<sstream>
+#include<vector>
+#include<cstdio>
+#include<typeinfo>
+#include<iostream>
+#include<cassert>
+#include<zlib.h>
+#include<map>
+
+namespace cnpy {
+
+    struct NpyArray {
+        char* data;
+        std::vector<unsigned int> shape;
+        unsigned int word_size;
+        bool fortran_order;
+        void destruct() {delete[] data;}
+    };
+
+    struct npz_t : public std::map<std::string, NpyArray>
+    {
+        void destruct()
+        {
+            npz_t::iterator it = this->begin();
+            for(; it != this->end(); ++it) (*it).second.destruct();
+        }
+    };
+
+    char BigEndianTest();
+    char map_type(const std::type_info& t);
+    template<typename T> std::vector<char> create_npy_header(const T* data, const unsigned int* shape, const unsigned int ndims);
+    void parse_npy_header(FILE* fp,unsigned int& word_size, unsigned int*& shape, unsigned int& ndims, bool& fortran_order);
+    void parse_zip_footer(FILE* fp, unsigned short& nrecs, unsigned int& global_header_size, unsigned int& global_header_offset);
+    npz_t npz_load(std::string fname);
+    NpyArray npz_load(std::string fname, std::string varname);
+    NpyArray npy_load(std::string fname);
+
+    template<typename T> std::vector<char>& operator+=(std::vector<char>& lhs, const T rhs) {
+        //write in little endian
+        for(char byte = 0; byte < sizeof(T); byte++) {
+            char val = *((char*)&rhs+byte);
+            lhs.push_back(val);
+        }
+        return lhs;
+    }
+
+    template<> std::vector<char>& operator+=(std::vector<char>& lhs, const std::string rhs);
+    template<> std::vector<char>& operator+=(std::vector<char>& lhs, const char* rhs);
+
+
+    template<typename T> std::string tostring(T i, int pad = 0, char padval = ' ') {
+        std::stringstream s;
+        s << i;
+        return s.str();
+    }
+
+    template<typename T> void npy_save(std::string fname, const T* data, const unsigned int* shape, const unsigned int ndims, std::string mode = "w") {
+        FILE* fp = NULL;
+
+        if(mode == "a") fp = fopen(fname.c_str(),"r+b");
+
+        if(fp) {
+            //file exists. we need to append to it. read the header, modify the array size
+            unsigned int word_size, tmp_dims;
+            unsigned int* tmp_shape = 0;
+            bool fortran_order;
+            parse_npy_header(fp,word_size,tmp_shape,tmp_dims,fortran_order);
+            assert(!fortran_order);
+
+            if(word_size != sizeof(T)) {
+                std::cout<<"libnpy error: "<<fname<<" has word size "<<word_size<<" but npy_save appending data sized "<<sizeof(T)<<"\n";
+                assert( word_size == sizeof(T) );
+            }
+            if(tmp_dims != ndims) {
+                std::cout<<"libnpy error: npy_save attempting to append misdimensioned data to "<<fname<<"\n";
+                assert(tmp_dims == ndims);
+            }
+
+            for(int i = 1; i < ndims; i++) {
+                if(shape[i] != tmp_shape[i]) {
+                    std::cout<<"libnpy error: npy_save attempting to append misshaped data to "<<fname<<"\n";
+                    assert(shape[i] == tmp_shape[i]);
+                }
+            }
+            tmp_shape[0] += shape[0];
+
+            fseek(fp,0,SEEK_SET);
+            std::vector<char> header = create_npy_header(data,tmp_shape,ndims);
+            fwrite(&header[0],sizeof(char),header.size(),fp);
+            fseek(fp,0,SEEK_END);
+
+            delete[] tmp_shape;
+        }
+        else {
+            fp = fopen(fname.c_str(),"wb");
+            std::vector<char> header = create_npy_header(data,shape,ndims);
+            fwrite(&header[0],sizeof(char),header.size(),fp);
+        }
+
+        unsigned int nels = 1;
+        for(int i = 0;i < ndims;i++) nels *= shape[i];
+
+        fwrite(data,sizeof(T),nels,fp);
+        fclose(fp);
+    }
+
+    template<typename T> void npz_save(std::string zipname, std::string fname, const T* data, const unsigned int* shape, const unsigned int ndims, std::string mode = "w")
+    {
+        //first, append a .npy to the fname
+    //    fname += ".npy";
+
+        //now, on with the show
+        FILE* fp = NULL;
+        unsigned short nrecs = 0;
+        unsigned int global_header_offset = 0;
+        std::vector<char> global_header;
+
+        if(mode == "a") fp = fopen(zipname.c_str(),"r+b");
+
+        if(fp) {
+            //zip file exists. we need to add a new npy file to it.
+            //first read the footer. this gives us the offset and size of the global header
+            //then read and store the global header.
+            //below, we will write the the new data at the start of the global header then append the global header and footer below it
+            unsigned int global_header_size;
+            parse_zip_footer(fp,nrecs,global_header_size,global_header_offset);
+            fseek(fp,global_header_offset,SEEK_SET);
+            global_header.resize(global_header_size);
+            size_t res = fread(&global_header[0],sizeof(char),global_header_size,fp);
+            if(res != global_header_size){
+                throw std::runtime_error("npz_save: header read error while adding to existing zip");
+            }
+            fseek(fp,global_header_offset,SEEK_SET);
+        }
+        else {
+            fp = fopen(zipname.c_str(),"wb");
+        }
+
+        std::vector<char> npy_header = create_npy_header(data,shape,ndims);
+
+        unsigned long nels = 1;
+        for (int m=0; m<ndims; m++ ) nels *= shape[m];
+        int nbytes = nels*sizeof(T) + npy_header.size();
+
+        //get the CRC of the data to be added
+        unsigned int crc = crc32(0L,(unsigned char*)&npy_header[0],npy_header.size());
+        crc = crc32(crc,(unsigned char*)data,nels*sizeof(T));
+
+        //build the local header
+        std::vector<char> local_header;
+        local_header += "PK"; //first part of sig
+        local_header += (unsigned short) 0x0403; //second part of sig
+        local_header += (unsigned short) 20; //min version to extract
+        local_header += (unsigned short) 0; //general purpose bit flag
+        local_header += (unsigned short) 0; //compression method
+        local_header += (unsigned short) 0; //file last mod time
+        local_header += (unsigned short) 0;     //file last mod date
+        local_header += (unsigned int) crc; //crc
+        local_header += (unsigned int) nbytes; //compressed size
+        local_header += (unsigned int) nbytes; //uncompressed size
+        local_header += (unsigned short) fname.size(); //fname length
+        local_header += (unsigned short) 0; //extra field length
+        local_header += fname;
+
+        //build global header
+        global_header += "PK"; //first part of sig
+        global_header += (unsigned short) 0x0201; //second part of sig
+        global_header += (unsigned short) 20; //version made by
+        global_header.insert(global_header.end(),local_header.begin()+4,local_header.begin()+30);
+        global_header += (unsigned short) 0; //file comment length
+        global_header += (unsigned short) 0; //disk number where file starts
+        global_header += (unsigned short) 0; //internal file attributes
+        global_header += (unsigned int) 0; //external file attributes
+        global_header += (unsigned int) global_header_offset; //relative offset of local file header, since it begins where the global header used to begin
+        global_header += fname;
+
+        //build footer
+        std::vector<char> footer;
+        footer += "PK"; //first part of sig
+        footer += (unsigned short) 0x0605; //second part of sig
+        footer += (unsigned short) 0; //number of this disk
+        footer += (unsigned short) 0; //disk where footer starts
+        footer += (unsigned short) (nrecs+1); //number of records on this disk
+        footer += (unsigned short) (nrecs+1); //total number of records
+        footer += (unsigned int) global_header.size(); //nbytes of global headers
+        footer += (unsigned int) (global_header_offset + nbytes + local_header.size()); //offset of start of global headers, since global header now starts after newly written array
+        footer += (unsigned short) 0; //zip file comment length
+
+        //write everything
+        fwrite(&local_header[0],sizeof(char),local_header.size(),fp);
+        fwrite(&npy_header[0],sizeof(char),npy_header.size(),fp);
+        fwrite(data,sizeof(T),nels,fp);
+        fwrite(&global_header[0],sizeof(char),global_header.size(),fp);
+        fwrite(&footer[0],sizeof(char),footer.size(),fp);
+        fclose(fp);
+    }
+
+    template<typename T> std::vector<char> create_npy_header(const T* data, const unsigned int* shape, const unsigned int ndims) {
+
+        std::vector<char> dict;
+        dict += "{'descr': '";
+        dict += BigEndianTest();
+        dict += map_type(typeid(T));
+        dict += tostring(sizeof(T));
+        dict += "', 'fortran_order': False, 'shape': (";
+        dict += tostring(shape[0]);
+        for(int i = 1;i < ndims;i++) {
+            dict += ", ";
+            dict += tostring(shape[i]);
+        }
+        if(ndims == 1) dict += ",";
+        dict += "), }";
+        //pad with spaces so that preamble+dict is modulo 16 bytes. preamble is 10 bytes. dict needs to end with \n
+        int remainder = 16 - (10 + dict.size()) % 16;
+        dict.insert(dict.end(),remainder,' ');
+        dict.back() = '\n';
+
+        std::vector<char> header;
+        header += (char) 0x93;
+        header += "NUMPY";
+        header += (char) 0x01; //major version of numpy format
+        header += (char) 0x00; //minor version of numpy format
+        header += (unsigned short) dict.size();
+        header.insert(header.end(),dict.begin(),dict.end());
+
+        return header;
+    }
+
+
+}
+
+#endif

src/films/mfilm.cpp

@@ -22,10 +22,11 @@
 #include <boost/algorithm/string.hpp>
 #include <boost/filesystem/fstream.hpp>
 #include <iomanip>
+#include "cnpy.h"
 
 MTS_NAMESPACE_BEGIN
 
-/*!\plugin{mfilm}{MATLAB / Mathematica film}
+/*!\plugin{mfilm}{MATLAB / Mathematica / NumPy film}
  * \order{4}
  * \parameters{
  *     \parameter{width, height}{\Integer}{
@@ -39,7 +40,7 @@ MTS_NAMESPACE_BEGIN
  *     }
  *     \parameter{fileFormat}{\String}{
  *       Specifies the desired output format; must be one of
- *       \code{matlab} or \code{mathematica}. \default{\code{matlab}}
+ *       \code{matlab}, \code{mathematica}, or \code{numpy}. \default{\code{matlab}}
  *     }
  *     \parameter{digits}{\Integer}{
  *       Number of significant digits to be written \default{4}
@@ -72,8 +73,8 @@ MTS_NAMESPACE_BEGIN
  * }
  *
  * This plugin provides a camera film that exports spectrum, RGB, XYZ, or
- * luminance values as a matrix to a MATLAB or Mathematica ASCII file. This is
+ * luminance values as a matrix to a MATLAB or Mathematica ASCII file or a NumPy binary file.
- * useful when running Mitsuba as simulation step as part of a
+ * This is useful when running Mitsuba as simulation step as part of a
  * larger virtual experiment. It can also come in handy when
  * verifying parts of the renderer using an automated test suite.
  */
@@ -81,7 +82,8 @@ class MFilm : public Film {
 public:
 	enum EMode {
 		EMATLAB = 0,
-		EMathematica
+		EMathematica,
+		ENumPy
 	};
 
 	MFilm(const Properties &props) : Film(props) {
@@ -122,9 +124,11 @@ public:
 			m_fileFormat = EMATLAB;
 		} else if (fileFormat == "mathematica") {
 			m_fileFormat = EMathematica;
+		} else if (fileFormat == "numpy") {
+			m_fileFormat = ENumPy;
 		} else {
 			Log(EError, "The \"fileFormat\" parameter must either be equal to "
-				"\"matlab\" or \"mathematica\"!");
+				"\"matlab\" or \"mathematica\" or \"numpy\" or \"numpycompressed\"!");
 		}
 
 		m_digits = props.getInteger("digits", 4);
@@ -246,83 +250,114 @@ public:
 
 		fs::path filename = m_destFile;
 		std::string extension = boost::to_lower_copy(filename.extension().string());
-		if (extension != ".m")
+		std::string expectedExtension;
-			filename.replace_extension(".m");
+		if (m_fileFormat == EMathematica || m_fileFormat == EMATLAB) {
+			expectedExtension = ".m";
+		} else if (m_fileFormat == ENumPy) {
+			expectedExtension = ".npy";
+		} else {
+			Log(EError, "Invalid file format!");
+		}
+		if (extension != expectedExtension)
+			filename.replace_extension(expectedExtension);
 
 		ref<Bitmap> bitmap = m_storage->getBitmap()->convert(
 			m_pixelFormat, Bitmap::EFloat);
 
 		Log(EInfo, "Writing image to \"%s\" ..", filename.filename().string().c_str());
 
-		fs::ofstream os(filename);
+		if (m_fileFormat == EMathematica || m_fileFormat == EMATLAB) {
-		if (!os.good() || os.fail())
+			fs::ofstream os(filename);
-			Log(EError, "Output file cannot be created!");
+			if (!os.good() || os.fail())
+				Log(EError, "Output file cannot be created!");
 
-		os << std::setprecision(m_digits);
+			os << std::setprecision(m_digits);
 
-		int rowSize = bitmap->getWidth();
+			int rowSize = bitmap->getWidth();
 
-		for (int ch=0; ch<bitmap->getChannelCount(); ++ch) {
+			for (int ch=0; ch<bitmap->getChannelCount(); ++ch) {
-			if (m_fileFormat == EMATLAB) {
+				if (m_fileFormat == EMATLAB) {
-				if (ch == 0) {
+					if (ch == 0) {
-					os << m_variable << " = [";
+						os << m_variable << " = [";
-				} else {
-					os << endl << m_variable << "(:, :, " << ch + 1 << ") = [";
-				}
-			} else {
-				if (ch == 0) {
-					if (bitmap->getChannelCount() == 1)
-						os << m_variable << " = {{";
-					else
-						os << m_variable << " = Transpose[{{{";
-				}
-			}
-			Float *ptr = bitmap->getFloatData();
-			ptr += ch;
-
-			for (int y=0; y < bitmap->getHeight(); y++) {
-				for (int x=0; x < rowSize; x++) {
-					if (m_fileFormat == EMATLAB) {
-						os << *ptr;
 					} else {
-						std::ostringstream oss;
+						os << endl << m_variable << "(:, :, " << ch + 1 << ") = [";
-						oss << *ptr;
-						std::string str = oss.str();
-						boost::replace_first(str, "e", " * 10^");
-						os << str;
 					}
+				} else {
+					if (ch == 0) {
+						if (bitmap->getChannelCount() == 1)
+							os << m_variable << " = {{";
+						else
+							os << m_variable << " = Transpose[{{{";
+					}
+				}
+				Float *ptr = bitmap->getFloatData();
+				ptr += ch;
 
-					ptr += bitmap->getChannelCount();
+				for (int y=0; y < bitmap->getHeight(); y++) {
-					if (x + 1 < rowSize) {
+					for (int x=0; x < rowSize; x++) {
-						os << ", ";
-					} else {
 						if (m_fileFormat == EMATLAB) {
-							if (y + 1 < bitmap->getHeight())
+							os << *ptr;
-								os << ";" << endl << "\t";
-							else
-								os << "];" << endl;
 						} else {
-							if (y + 1 < bitmap->getHeight()) {
+							std::ostringstream oss;
-								os << "}," << endl << "\t{";
+							oss << *ptr;
-							} else if (ch + 1 == bitmap->getChannelCount()){
+							std::string str = oss.str();
-								if (bitmap->getChannelCount() == 1)
+							boost::replace_first(str, "e", " * 10^");
-									os << "}};" << endl;
+							os << str;
+						}
+
+						ptr += bitmap->getChannelCount();
+						if (x + 1 < rowSize) {
+							os << ", ";
+						} else {
+							if (m_fileFormat == EMATLAB) {
+								if (y + 1 < bitmap->getHeight())
+									os << ";" << endl << "\t";
 								else
-									os << "}}}, {3,1,2}];" << endl;
+									os << "];" << endl;
 							} else {
-								os << "}}," << endl << endl << "\t{{";
+								if (y + 1 < bitmap->getHeight()) {
+									os << "}," << endl << "\t{";
+								} else if (ch + 1 == bitmap->getChannelCount()){
+									if (bitmap->getChannelCount() == 1)
+										os << "}};" << endl;
+									else
+										os << "}}}, {3,1,2}];" << endl;
+								} else {
+									os << "}}," << endl << endl << "\t{{";
+								}
 							}
 						}
 					}
 				}
 			}
+		} else {
+			unsigned int shape[] = {
+				bitmap->getHeight(),
+				bitmap->getWidth(),
+				bitmap->getChannelCount()
+			};
+			unsigned int N = 3, *shape_ptr = shape;
+
+			if (bitmap->getChannelCount() == 1)
+				N = 2;
+
+			const Float *data = bitmap->getFloatData();
+			cnpy::npy_save(filename.string(), data, shape_ptr, N, "w");
 		}
 	}
 
 	bool destinationExists(const fs::path &baseName) const {
 		fs::path filename = baseName;
-		if (boost::to_lower_copy(filename.extension().string()) != ".m")
+		std::string expectedExtension;
-			filename.replace_extension(".m");
+		if (m_fileFormat == EMathematica || m_fileFormat == EMATLAB) {
+			expectedExtension = ".m";
+		} else if (m_fileFormat == ENumPy) {
+			expectedExtension = ".npy";
+		} else {
+			Log(EError, "Invalid file format!");
+		}
+		if (boost::to_lower_copy(filename.extension().string()) != expectedExtension)
+			filename.replace_extension(expectedExtension);
 		return fs::exists(filename);
 	}
 
@@ -359,5 +394,5 @@ protected:
 };
 
 MTS_IMPLEMENT_CLASS_S(MFilm, false, Film)
-MTS_EXPORT_PLUGIN(MFilm, "MATLAB / Mathematica film");
+MTS_EXPORT_PLUGIN(MFilm, "MATLAB / Mathematica / NumPy film");
 MTS_NAMESPACE_END