Skip to content

Commit

Permalink
add las extra bytes infos reading
Browse files Browse the repository at this point in the history
  • Loading branch information
@NEDJIMAbelgacem @wonder-sk
NEDJIMAbelgacem authored and wonder-sk committed Feb 1, 2022
1 parent 65287ee commit 1dbc4a2
Showing 1 changed file with 161 additions and 3 deletions.
164 changes: 161 additions & 3 deletions src/core/pointcloud/qgseptdecoder.cpp
View file
Expand Up @@ -28,6 +28,7 @@
#include <memory>
#include <cstring>
#include <QTemporaryFile>
#include <string>

#include <zstd.h>

Expand Down Expand Up @@ -268,6 +269,138 @@ QgsPointCloudBlock *QgsEptDecoder::decompressZStandard( const QByteArray &data,

/* *************************************************************************************** */

struct ExtraBytesAttributeDetails
{
ExtraBytesAttributeDetails( const QString &attribute, QgsPointCloudAttribute::DataType type, int size, int offset )
: attribute( attribute )
, type( type )
, size( size )
, offset( offset )
{}

QString attribute;
QgsPointCloudAttribute::DataType type;
int size;
int offset;
};

template<typename FileType>
QVector<ExtraBytesAttributeDetails> readExtraByteAttributes( laszip::io::reader::basic_file<FileType> &f, FileType &file )
{
auto pastFilePos = file.tellg();

// Read VLR stuff

struct VlrHeader
{
unsigned short reserved;
char user_id[16];
unsigned short record_id;
unsigned short record_length;
char desc[32];
};

struct ExtraByteDescriptor
{
unsigned char reserved[2]; // 2 bytes
unsigned char data_type; // 1 byte
unsigned char options; // 1 byte
char name[32]; // 32 bytes
unsigned char unused[4]; // 4 bytes
unsigned char no_data[8]; // 8 bytes
unsigned char deprecated1[16]; // 16 bytes
unsigned char min[8]; // 8 bytes
unsigned char deprecated2[16]; // 16 bytes
unsigned char max[8]; // 8 bytes
unsigned char deprecated3[16]; // 16 bytes
unsigned char scale[8]; // 8 bytes
unsigned char deprecated4[16]; // 16 bytes
double offset; // 8 bytes
unsigned char deprecated5[16]; // 16 bytes
char description[32]; // 32 bytes
};

QVector<ExtraByteDescriptor> extraBytes;
QVector<ExtraBytesAttributeDetails> extrabytesAttr;

VlrHeader extraBytesVlrHeader;
int extraBytesDescriptorsOffset = -1;

file.seekg( f.get_header().header_size );
for ( unsigned int i = 0; i < f.get_header().vlr_count && file.good() && !file.eof(); ++i )
{
VlrHeader vlrHeader;
file.read( ( char * )&vlrHeader, sizeof( VlrHeader ) );
file.seekg( vlrHeader.record_length, std::ios::cur );
if ( std::equal( vlrHeader.user_id, vlrHeader.user_id + 9, "LASF_Spec" ) && vlrHeader.record_id == 4 )
{
extraBytesVlrHeader = vlrHeader;
extraBytesDescriptorsOffset = f.get_header().header_size + sizeof( VlrHeader );
}
}

// Read VLR fields
if ( extraBytesDescriptorsOffset != -1 )
{
file.seekg( extraBytesDescriptorsOffset );
int n_descriptors = extraBytesVlrHeader.record_length / sizeof( ExtraByteDescriptor );
for ( int i = 0; i < n_descriptors; ++i )
{
ExtraByteDescriptor ebd;
file.read( ( char * )&ebd, sizeof( ExtraByteDescriptor ) );
extraBytes.push_back( ebd );
}
}

for ( ExtraByteDescriptor &eb : extraBytes )
{
int accOffset = extrabytesAttr.empty() ? 0 : extrabytesAttr.back().offset + extrabytesAttr.back().size;
// TODO: manage other data types
switch ( eb.data_type )
{
case 0:
extrabytesAttr.push_back( ExtraBytesAttributeDetails( QString::fromStdString( eb.name ), QgsPointCloudAttribute::Char, eb.options, accOffset ) );
break;
case 1:
extrabytesAttr.push_back( ExtraBytesAttributeDetails( QString::fromStdString( eb.name ), QgsPointCloudAttribute::Char, 1, accOffset ) );
break;
case 2:
extrabytesAttr.push_back( ExtraBytesAttributeDetails( QString::fromStdString( eb.name ), QgsPointCloudAttribute::Char, 1, accOffset ) );
break;
case 3:
extrabytesAttr.push_back( ExtraBytesAttributeDetails( QString::fromStdString( eb.name ), QgsPointCloudAttribute::UShort, 2, accOffset ) );
break;
case 4:
extrabytesAttr.push_back( ExtraBytesAttributeDetails( QString::fromStdString( eb.name ), QgsPointCloudAttribute::Short, 2, accOffset ) );
break;
case 5:
extrabytesAttr.push_back( ExtraBytesAttributeDetails( QString::fromStdString( eb.name ), QgsPointCloudAttribute::Int32, 4, accOffset ) );
break;
case 6:
extrabytesAttr.push_back( ExtraBytesAttributeDetails( QString::fromStdString( eb.name ), QgsPointCloudAttribute::Int32, 4, accOffset ) );
break;
case 7:
extrabytesAttr.push_back( ExtraBytesAttributeDetails( QString::fromStdString( eb.name ), QgsPointCloudAttribute::Int32, 8, accOffset ) );
break;
case 8:
extrabytesAttr.push_back( ExtraBytesAttributeDetails( QString::fromStdString( eb.name ), QgsPointCloudAttribute::Int32, 8, accOffset ) );
break;
case 9:
extrabytesAttr.push_back( ExtraBytesAttributeDetails( QString::fromStdString( eb.name ), QgsPointCloudAttribute::Float, 4, accOffset ) );
break;
case 10:
extrabytesAttr.push_back( ExtraBytesAttributeDetails( QString::fromStdString( eb.name ), QgsPointCloudAttribute::Double, 8, accOffset ) );
break;
default:
break;
}
}

file.seekg( pastFilePos );

return extrabytesAttr;
}

template<typename FileType>
QgsPointCloudBlock *__decompressLaz( FileType &file, const QgsPointCloudAttributeCollection &attributes, const QgsPointCloudAttributeCollection &requestedAttributes, const QgsVector3D &_scale, const QgsVector3D &_offset )
{
Expand Down Expand Up @@ -318,22 +451,27 @@ QgsPointCloudBlock *__decompressLaz( FileType &file, const QgsPointCloudAttribut
Red,
Green,
Blue,
ExtraBytes,
MissingOrUnknown
};

struct RequestedAttributeDetails
{
RequestedAttributeDetails( LazAttribute attribute, QgsPointCloudAttribute::DataType type, int size )
RequestedAttributeDetails( LazAttribute attribute, QgsPointCloudAttribute::DataType type, int size, int offset = -1 )
: attribute( attribute )
, type( type )
, size( size )
, offset( offset )
{}

LazAttribute attribute;
QgsPointCloudAttribute::DataType type;
int size;
int offset; // Used in case the attribute is an extra byte attribute
};

QVector<ExtraBytesAttributeDetails> extrabytesAttr = readExtraByteAttributes<FileType>( f, file );

std::vector< RequestedAttributeDetails > requestedAttributeDetails;
requestedAttributeDetails.reserve( requestedAttributesVector.size() );
for ( const QgsPointCloudAttribute &requestedAttribute : requestedAttributesVector )
Expand Down Expand Up @@ -404,8 +542,21 @@ QgsPointCloudBlock *__decompressLaz( FileType &file, const QgsPointCloudAttribut
}
else
{
// this can possibly happen -- e.g. if a style built using a different point cloud format references an attribute which isn't available from the laz file
requestedAttributeDetails.emplace_back( RequestedAttributeDetails( LazAttribute::MissingOrUnknown, requestedAttribute.type(), requestedAttribute.size() ) );
bool foundAttr = false;
for ( ExtraBytesAttributeDetails &eba : extrabytesAttr )
{
if ( requestedAttribute.name().compare( eba.attribute.trimmed() ) )
{
requestedAttributeDetails.emplace_back( RequestedAttributeDetails( LazAttribute::ExtraBytes, requestedAttribute.type(), requestedAttribute.size(), eba.offset ) );
foundAttr = true;
break;
}
}
if ( !foundAttr )
{
// this can possibly happen -- e.g. if a style built using a different point cloud format references an attribute which isn't available from the laz file
requestedAttributeDetails.emplace_back( RequestedAttributeDetails( LazAttribute::MissingOrUnknown, requestedAttribute.type(), requestedAttribute.size() ) );
}
}
}

Expand All @@ -416,6 +567,7 @@ QgsPointCloudBlock *__decompressLaz( FileType &file, const QgsPointCloudAttribut
const laszip::formats::las::gpstime gps = laszip::formats::packers<laszip::formats::las::gpstime>::unpack( buf + sizeof( laszip::formats::las::point10 ) );
const laszip::formats::las::rgb rgb = laszip::formats::packers<laszip::formats::las::rgb>::unpack( buf + sizeof( laszip::formats::las::point10 ) + sizeof( laszip::formats::las::gpstime ) );

char *ebbuf = buf + sizeof( laszip::formats::las::point10 ) + sizeof( laszip::formats::las::gpstime ) + sizeof( laszip::formats::las::rgb );
for ( const RequestedAttributeDetails &requestedAttribute : requestedAttributeDetails )
{
switch ( requestedAttribute.attribute )
Expand Down Expand Up @@ -470,6 +622,12 @@ QgsPointCloudBlock *__decompressLaz( FileType &file, const QgsPointCloudAttribut
case LazAttribute::Blue:
_storeToStream<unsigned short>( dataBuffer, outputOffset, requestedAttribute.type, rgb.b );
break;
case LazAttribute::ExtraBytes:
{
for ( int i = 0; i < requestedAttribute.size; ++i )
dataBuffer[outputOffset] = ebbuf[requestedAttribute.offset + i];
}
break;
case LazAttribute::MissingOrUnknown:
// just store 0 for unknown/missing attributes
_storeToStream<unsigned short>( dataBuffer, outputOffset, requestedAttribute.type, 0 );
Expand Down

0 comments on commit 1dbc4a2

Please sign in to comment.