417 lines
12 KiB
C++
417 lines
12 KiB
C++
// PNM Reader -- Written by Eric Sokolowsky
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// Reads Ascii and Binary files in the PPM, PGM, and PBM formats.
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#include <osg/Image>
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#include <osg/Notify>
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#include <osg/Endian>
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#include <osgDB/Registry>
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#include <osgDB/FileNameUtils>
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#include <osgDB/FileUtils>
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#include <stdio.h>
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using namespace osg;
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template <class T>
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unsigned char* read_bitmap_ascii(FILE* fp, int width, int height)
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{
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T* data = new T[width*height];
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T* dst = data;
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T* end = data + width*height;
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while(dst < end)
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{
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T value = 0;
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// read in characters looking for '0's and '1's, these
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// values map to 255 and 0. Any other characters
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// are silently ignored.
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while(1)
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{
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int ch = fgetc(fp);
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if (feof(fp) || ferror(fp))
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{
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fclose(fp);
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delete [] data;
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return NULL;
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}
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if (ch == '0')
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{
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value = 255;
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break;
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}
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else if (ch == '1')
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{
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value = 0;
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break;
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}
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}
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// place value in the image
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*(dst++) = value;
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}
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return reinterpret_cast<unsigned char*>(data);
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}
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template <class T>
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unsigned char* read_grayscale_ascii(FILE* fp, int width, int height)
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{
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T* data = new T[width*height];
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T* dst = data;
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T* end = data + width*height;
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while(dst < end)
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{
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int ch;
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T value = 0;
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// read and discard any whitespace
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// until a digit is reached
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do
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{
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ch = fgetc(fp);
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if (feof(fp) || ferror(fp))
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{
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fclose(fp);
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delete [] data;
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return NULL;
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}
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}
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while(!isdigit(ch));
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// continue reading digits and incrementally
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// construct the integer value
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do
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{
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value = 10*value + (ch - '0');
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ch = fgetc(fp);
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if (feof(fp) || ferror(fp))
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{
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fclose(fp);
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delete [] data;
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return NULL;
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}
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}
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while(isdigit(ch));
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// place value in the image
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*(dst++) = value;
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}
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return reinterpret_cast<unsigned char*>(data);
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}
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template <class T>
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unsigned char* read_color_ascii(FILE* fp, int width, int height)
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{
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T* data = new T[3*width*height];
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T* dst = data;
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T* end = data + 3*width*height;
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while(dst < end)
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{
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int ch;
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T value = 0;
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// read and discard any whitespace
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// until a digit is reached
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do
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{
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ch = fgetc(fp);
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if (feof(fp) || ferror(fp))
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{
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fclose(fp);
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delete [] data;
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return NULL;
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}
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}
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while(!isdigit(ch));
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// continue reading digits and incrementally
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// construct the integer value
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do
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{
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value = 10*value + (ch - '0');
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ch = fgetc(fp);
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if (feof(fp) || ferror(fp))
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{
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fclose(fp);
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delete [] data;
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return NULL;
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}
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}
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while(isdigit(ch));
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// place value in the image
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*(dst++) = value;
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}
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return reinterpret_cast<unsigned char*>(data);
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}
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template <class T>
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unsigned char* read_bitmap_binary(FILE* fp, int width, int height)
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{
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T* data = new T[width*height];
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for(int y = 0; y < height; y++)
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{
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T* dst = data + (y+0)*width;
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T* end = data + (y+1)*width;
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while(dst < end)
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{
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unsigned char b = fgetc(fp);
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if (feof(fp) || ferror(fp))
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{
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fclose(fp);
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delete [] data;
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return NULL;
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}
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for(int i = 7; i >= 0 && dst < end; i--)
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{
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// 1 means black, 0 means white
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T data_value = (b & (1<<i)) ? 0 : 255;
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*(dst++) = data_value;
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}
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}
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}
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return reinterpret_cast<unsigned char*>(data);
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}
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template <class T>
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unsigned char* read_grayscale_binary(FILE* fp, int width, int height)
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{
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T* data = new T[width*height];
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if (fread(data, sizeof(T)*width*height, 1, fp) != 1)
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{
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fclose(fp);
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delete [] data;
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return NULL;
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}
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// if the machine is little endian swap the bytes around
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if (sizeof(T) > 1 && getCpuByteOrder() == osg::LittleEndian)
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{
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for(int i = 0; i < width*height; i++)
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{
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unsigned char* bs = (unsigned char*)(&data[i]);
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std::swap(bs[0], bs[1]);
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}
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}
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return reinterpret_cast<unsigned char*>(data);
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}
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template <class T>
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unsigned char* read_color_binary(FILE* fp, int width, int height)
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{
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T* data = new T[3*width*height];
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if (fread(data, 3*sizeof(T)*width*height, 1, fp) != 1)
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{
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fclose(fp);
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delete [] data;
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return NULL;
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}
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// if the machine is little endian swap the bytes around
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if (sizeof(T) > 1 && getCpuByteOrder() == osg::LittleEndian)
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{
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for(int i = 0; i < 3*width*height; i++)
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{
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unsigned char* bs = (unsigned char*)(&data[i]);
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std::swap(bs[0], bs[1]);
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}
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}
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return reinterpret_cast<unsigned char*>(data);
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}
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class ReaderWriterPNM : public osgDB::ReaderWriter
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{
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public:
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virtual const char* className() const { return "PNM Image Reader/Writer"; }
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virtual bool acceptsExtension(const std::string& extension) const
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{
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return osgDB::equalCaseInsensitive(extension, "pnm") ||
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osgDB::equalCaseInsensitive(extension, "ppm") ||
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osgDB::equalCaseInsensitive(extension, "pgm") ||
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osgDB::equalCaseInsensitive(extension, "pbm");
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}
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virtual ReadResult readImage(const std::string& file, const osgDB::ReaderWriter::Options* options) const
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{
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std::string ext = osgDB::getLowerCaseFileExtension(file);
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if (!acceptsExtension(ext)) return ReadResult::FILE_NOT_HANDLED;
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std::string fileName = osgDB::findDataFile( file, options );
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if (fileName.empty()) return ReadResult::FILE_NOT_FOUND;
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FILE *fp = NULL;
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char line[300];
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int ppmtype = 0; /* P1, P2, etc. */
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int width = 0;
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int height = 0;
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int max_value = 0;
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// Open file.
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fp = fopen(fileName.c_str(), "rb");
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// Read header items.
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int row;
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for (row = 1; row <= 3; row++)
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{
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fgets(line, 300, fp);
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char *cp = line;
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while (*cp && isspace(*cp))
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cp++;
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if (! *cp || *cp == '#')
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{
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// Skip comment lines.
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row--;
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}
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else if (row == 1)
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{
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// Get the image type.
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if (line[0] == 'p' || line[0] == 'P')
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{
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ppmtype = line[1] - '0';
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}
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}
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else if (row == 2)
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{
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// Get the image size.
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width = atoi(line);
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char *cp = line + strspn(line, "\t \n\r");
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cp += strspn(cp, "0123456789");
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cp += strspn(line, "\t \n\r");
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height = atoi(cp);
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// pbm files don't have row 3
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if (ppmtype == 1 || ppmtype == 4)
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{
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max_value = 1;
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break;
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}
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}
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else if (row == 3)
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{
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// Get the maximum value
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max_value = atoi(line);
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}
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}
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// Check for valid values.
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if (width <= 0 || height <= 0 ||
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max_value <= 0 || max_value > 65535 ||
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ppmtype < 1 || ppmtype > 6)
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{
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fclose(fp);
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return ReadResult::FILE_NOT_HANDLED;
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}
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int pixelFormat = 0;
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int dataType = 0;
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unsigned char* data = NULL;
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if (max_value > 255)
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{
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dataType = GL_UNSIGNED_SHORT;
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switch(ppmtype)
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{
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case 1: // bitmap ascii
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pixelFormat = GL_LUMINANCE;
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data = read_bitmap_ascii<unsigned short>(fp, width, height);
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break;
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case 2: // grayscale ascii
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pixelFormat = GL_LUMINANCE;
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data = read_grayscale_ascii<unsigned short>(fp, width, height);
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break;
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case 3: // color ascii
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pixelFormat = GL_RGB;
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data = read_color_ascii<unsigned short>(fp, width, height);
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break;
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case 4: // bitmap binary
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pixelFormat = GL_LUMINANCE;
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data = read_bitmap_binary<unsigned short>(fp, width, height);
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break;
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case 5: // grayscale binary
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pixelFormat = GL_LUMINANCE;
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data = read_grayscale_binary<unsigned short>(fp, width, height);
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break;
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case 6: // color binary
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pixelFormat = GL_RGB;
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data = read_color_binary<unsigned short>(fp, width, height);
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break;
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}
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}
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else
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{
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dataType = GL_UNSIGNED_BYTE;
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switch(ppmtype)
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{
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case 1: // bitmap ascii
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pixelFormat = GL_LUMINANCE;
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data = read_bitmap_ascii<unsigned char>(fp, width, height);
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break;
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case 2: // grayscale ascii
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pixelFormat = GL_LUMINANCE;
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data = read_grayscale_ascii<unsigned char>(fp, width, height);
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break;
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case 3: // color ascii
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pixelFormat = GL_RGB;
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data = read_color_ascii<unsigned char>(fp, width, height);
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break;
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case 4: // bitmap binary
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pixelFormat = GL_LUMINANCE;
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data = read_bitmap_binary<unsigned char>(fp, width, height);
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break;
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case 5: // grayscale binary
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pixelFormat = GL_LUMINANCE;
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data = read_grayscale_binary<unsigned char>(fp, width, height);
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break;
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case 6: // color binary
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pixelFormat = GL_RGB;
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data = read_color_binary<unsigned char>(fp, width, height);
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break;
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}
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}
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if (data == NULL)
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{
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fclose(fp);
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return ReadResult::FILE_NOT_HANDLED;
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}
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if (fp)
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fclose(fp);
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osg::Image* pOsgImage = new osg::Image();
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pOsgImage->setFileName(fileName.c_str());
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pOsgImage->setImage(width, height, 1,
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pixelFormat,
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pixelFormat,
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dataType,
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data,
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osg::Image::USE_NEW_DELETE);
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return pOsgImage;
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}
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};
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// now register with Registry to instantiate the above
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// reader/writer.
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osgDB::RegisterReaderWriterProxy<ReaderWriterPNM> g_readerWriter_PNM_Proxy;
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