void savePicAsHeightMap( std::string const& infile, std::string const& outfile ) {
ImageIO::init();
BitMap* in = ImageIO::load( infile );
BitMap* out = new BitMap( in->getWidth(), in->getHeight() );
for( int j=0; j<in->getHeight(); j++ ) {
for( int i=0; i<in->getWidth(); i++ ) {
unsigned int col = in->get( i, j );
int r = ( col >> 16 ) & 0xff;
int g = ( col >> 8 ) & 0xff;
int b = col & 0xff;
int v = (int)( (double)r * 0.2125 + (double)g * 0.7154 + (double)b * 0.0721 ) & 0xff;
out->set( i, j, ( 0xff << 24 ) | ( v << 16 ) | ( v << 8 ) | v );
}
}
ImageIO::save( outfile, *out );
delete out;
delete in;
}
BitMap* BMP::load( std::string const& filename ) {
FILE* f = fopen( filename.c_str(), "rb" );
assert( f );
// bitmap file header
unsigned short bfType;
unsigned int bfSize;
unsigned short bfReserved1;
unsigned short bfReserved2;
unsigned int bfOffbits;
fread( &bfType, 2, 1, f );
fread( &bfSize, 4, 1, f );
fread( &bfReserved1, 2, 1, f );
fread( &bfReserved2, 2, 1, f );
fread( &bfOffbits, 4, 1, f );
// bitmap info header
unsigned int biSize;
int biWidth;
int biHeight;
unsigned short biPlanes;
unsigned short biBitCount;
unsigned int biCompression;
unsigned int biSizeImage;
int biXPelsPerMeter;
int biYPelsPerMeter;
unsigned int biClrUsed;
unsigned int biClrImportant;
fread( &biSize, 4, 1, f );
fread( &biWidth, 4, 1, f );
fread( &biHeight, 4, 1, f );
fread( &biPlanes, 2, 1, f );
fread( &biBitCount, 2, 1, f );
fread( &biCompression, 4, 1, f );
fread( &biSizeImage, 4, 1, f );
fread( &biXPelsPerMeter, 4, 1, f );
fread( &biYPelsPerMeter, 4, 1, f );
fread( &biClrUsed, 4, 1, f );
fread( &biClrImportant, 4, 1, f );
BitMap* m = new BitMap( biWidth, biHeight );
// read data
for( int j=0; j<biHeight; j++ ) {
for( int i=0; i<biWidth; i++ ) {
unsigned char a, r, g, b;
fread( &b, 1, 1, f );
fread( &g, 1, 1, f );
fread( &r, 1, 1, f );
if( biBitCount == 32 )
fread( &a, 1, 1, f );
else if( biBitCount == 24 )
a = 0xff;
m->set( i, biHeight - j - 1, ( a << 24 ) | ( b << 16 ) | ( g << 8 ) | r );
}
}
fclose( f );
return m;
}