This commit provides support for each slice to have an origin
specified relative to the sequence bounding box.

Reconstructed points are offset by the slice origin prior to inverse
scaling and translation.

With slice/tile-based coding, it is necessary to build an output
point cloud from independent slice/tiles.  An append operation allows
the points of two point clouds to be concatenated.

Vladyslav Zakharchenko authored Dec 14, 2018 and David Flynn committed Feb 06, 2019

This uses a binary-tree to generate the levels-of-details for the
lifting/predicting transforms as an alternative to Euclidean distance
thresholding methods.

Jungsun Kim authored Jan 30, 2019 and David Flynn committed Feb 05, 2019

This simplified attribute prediction scheme avoids computing the
LoD structure in order to reduce the computational complexity of
both the encoder and the decoder.  It is activated by setting
levelOfDetailCount=0.

NB: this is only configured for lossless/near-lossless predictive
attribute coding of cat3 sequences.

Danillo Bracco Graziosi authored Dec 12, 2018 and David Flynn committed Feb 05, 2019

This replaces the previous floating point transform implementation with
a fixed-point alternative with essentially identical compression
performance.

Ohji Nakagami authored Feb 04, 2019 and David Flynn committed Feb 05, 2019

This commit provides an integer approximation of atan2().

Ohji Nakagami authored Nov 26, 2018 and David Flynn committed Feb 05, 2019

This replaces the previous floating point version.  The number of
fractional bits is set to 8, allowing 24bit (unsigned) geometry
to be represented in 32bit calculations with negligible effects
on the reconstruction.

 - calculates the sequence bounding box at the start of encoding
   (in original coordinates as a decoder may reconstruct it)
 - signals bounding box in SPS
 - disables signalling of geometry box origin (always 0)

The configuration parameters seq_bounding_box_xyz0 and
seq_bounding_box_whd allow overriding the automatic derivation of
frame (sequence) bounding box, forcing the depth of the geometry
tree.

NB: seq_bounding_box_xyz0 and seq_bounding_box_whd are specified
    using unscaled co-ordinates.

NB: this patch does not signal these parameters in the SPS.

Define po-lite option traits to handle PCCVector3<T> as a container
to permit using PCCVector3<T> types as command / config parameters.

The generic option handling for containers assumes that the container
type provides clear(), push_back() and iterator methods.  Beyond being
insufficiently general, the template matches any template template
type, preventing use of the non template template template.

This commit provides a traits-based method to (a) conditionally
apply the template template Option definition, and (b) to provide
methods appropriate for a particular container.

 - signal geom_slice_id / attr_geom_slice_id in geometry / attribute
   header.

 - attr_geom_slice_id set to current geom_slice_id to maintain
   relationship between attribute and geometry.

 - increment geom_slice_id after each round of encoding.

 - decoder checks that the attribute payload's attr_geom_slice_id
   corresponds to the most recently decoded geometry payload.

Each occupancy bit is contextualised based on the number of occupied
(directly) adjacent child nodes in the (x-1), (y-1), and (z-1)
neighbour nodes used to generate the neighbour pattern.

Three contextualisation states are added:
 - no adjacent neighbours
 - one adjacent neigbour (=adjacencyGt0)
 - two adjacent neighoburs (=adjacencyGt1)

The neighbour pattern for a node indicates occupied neighbouring nodes.

This commit updates the definition of occupancy for the (x-1), (y-1),
and (z-1) neighbours to be occupied if the neighbour's adjoining
children (ie sharing a face with the current node) are occupied.

In the 1-D figure below, at a depth d, the node 'X' has two occupied
neighbours 'R' and 'L'.  When determining the neighbour pattern of X,
the (x-1) state of the neighbour's adjoining child ('r') is used
instead.  For completeness, nodes marked with '?' are not causally
available.

  d+0:   R|X|L
  d+1:  Rr|??|??

Replaces the existing map update tables (generated from (L*p+s)/(L+1),
memory L=10) with an adaptive memory (L=max(5, 1/p, 1/(1-p)) clipped
to 200) represented as delta transitions and quantised to 16 entries.

This commit provides trisoup_node_size_log2 as a replacement for
the following HLS syntax variables:
 - geom_codec_type (redundant wrt. triangle node size derivation)
 - trisoup_depth (redundant wrt. bounding box)
 - trisoup_triangle_level (semantics simplified)

The following config options have been removed:
 - geometryCodec (redundant wrt. trisoup_node_size_log2)
 - triSoupLevel  (replaced by trisoup_node_size_log2)
 - triSoupDepth  (unnecessary)
 - triSoupIntToOrigScale (redundant wrt. positionQuantizationScale)

Min Ku Lee authored Jan 30, 2019 and David Flynn committed Feb 05, 2019

Using the Rec.709 colour matrix with full range RGB signals, it is
necessary to clip the output to avoid exceeding the attribute bitdepth.

A leaf node by definition contains at least one point.  Therefore the
single point flag indicates if there are one or two points in the leaf.
The remainder should be signalled as numpoints - 2 as per the working
draft text.

The --only-seqs and --exclude-seqs options permit limiting config
generation to a specified set of named sequences and to exclude
named sequences respectively.

Both options take a colon separated list of names.

This commit generates trisoup-raht configuration files using RAHT
rather than the lifting transform.

Khaled Mammou authored Sep 22, 2018 and David Flynn committed Nov 01, 2018

Replace the k-d tree based nearest neighbour search with an approximate
search based upon the points in Morton order.

Toshiyasu Sugio authored Sep 20, 2018 and David Flynn committed Nov 01, 2018

This commit provides an ability to vary the number of direct neighbours
used in the predicting transform.  Mode 0 corresponds to the existing
averaging, and mode n selects the n-th nearest neighbour for direct
prediction.

The provided code has been reworked to:
 - rewrite unary coding to be a little more obvious
 - tidy the mode decision path
 - add configuration for max_num_direct_predictors (renamed from
   MaxNumPredCand)
 - now counts the number of single predictors, rather than prediction
   modes.

This commit provides an implementation of the entropy coding interface
using the dirac (schroedinger) arithmetic codec.

In order to handle any remaining m-ary symbols, a naïve unary
binarisation is employed.

This includes the removal of dirac specific context chains used in
exp-golomb prefix coding.

This commit imports an implementation of the dirac arithmetic codec
from the third party schroedinger-1.0.11 library.