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Differential D4501 Diff 14677 extern/draco/dracoenc/src/draco/compression/point_cloud/algorithms/integer_points_kd_tree_encoder.h

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extern/draco/dracoenc/src/draco/compression/point_cloud/algorithms/integer_points_kd_tree_encoder.h

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// Copyright 2016 The Draco Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// TODO(hemmer): Make this a wrapper using DynamicIntegerPointsKdTreeEncoder.
#ifndef DRACO_COMPRESSION_POINT_CLOUD_ALGORITHMS_INTEGER_POINTS_KD_TREE_ENCODER_H_
#define DRACO_COMPRESSION_POINT_CLOUD_ALGORITHMS_INTEGER_POINTS_KD_TREE_ENCODER_H_
#include <algorithm>
#include <array>
#include <memory>
#include <vector>
#include "draco/compression/bit_coders/adaptive_rans_bit_encoder.h"
#include "draco/compression/bit_coders/direct_bit_encoder.h"
#include "draco/compression/bit_coders/folded_integer_bit_encoder.h"
#include "draco/compression/bit_coders/rans_bit_encoder.h"
#include "draco/compression/point_cloud/algorithms/point_cloud_types.h"
#include "draco/compression/point_cloud/algorithms/queuing_policy.h"
#include "draco/core/bit_utils.h"
#include "draco/core/encoder_buffer.h"
#include "draco/core/math_utils.h"
namespace draco {
// This policy class provides several configurations for the encoder that allow
// to trade speed vs compression rate. Level 0 is fastest while 10 is the best
// compression rate. The decoder must select the same level.
template <int compression_level_t>
struct IntegerPointsKdTreeEncoderCompressionPolicy
: public IntegerPointsKdTreeEncoderCompressionPolicy<compression_level_t -
1> {};
template <>
struct IntegerPointsKdTreeEncoderCompressionPolicy<0> {
typedef DirectBitEncoder NumbersEncoder;
typedef DirectBitEncoder AxisEncoder;
typedef DirectBitEncoder HalfEncoder;
typedef DirectBitEncoder RemainingBitsEncoder;
static constexpr bool select_axis = false;
template <class T>
using QueuingStrategy = Stack<T>;
};
template <>
struct IntegerPointsKdTreeEncoderCompressionPolicy<2>
: public IntegerPointsKdTreeEncoderCompressionPolicy<1> {
typedef RAnsBitEncoder NumbersEncoder;
};
template <>
struct IntegerPointsKdTreeEncoderCompressionPolicy<4>
: public IntegerPointsKdTreeEncoderCompressionPolicy<3> {
typedef FoldedBit32Encoder<RAnsBitEncoder> NumbersEncoder;
};
template <>
struct IntegerPointsKdTreeEncoderCompressionPolicy<6>
: public IntegerPointsKdTreeEncoderCompressionPolicy<5> {
static constexpr bool select_axis = true;
};
template <>
struct IntegerPointsKdTreeEncoderCompressionPolicy<8>
: public IntegerPointsKdTreeEncoderCompressionPolicy<7> {
typedef FoldedBit32Encoder<AdaptiveRAnsBitEncoder> NumbersEncoder;
template <class T>
using QueuingStrategy = Queue<T>;
};
template <>
struct IntegerPointsKdTreeEncoderCompressionPolicy<10>
: public IntegerPointsKdTreeEncoderCompressionPolicy<9> {
template <class T>
using QueuingStrategy = PriorityQueue<T>;
};
// This class encodes a given integer point cloud based on the point cloud
// compression algorithm in:
// Olivier Devillers and Pierre-Marie Gandoin
// "Geometric compression for interactive transmission"
//
// In principle the algorithm keeps on splitting the point cloud in the middle
// while alternating the axes. In 3D this results in an Octree like structure.
// In each step we encode the number of points in the first half.
// The algorithm does not preserve the order of points.
//
// However, the algorithm here differs from the original as follows:
// The algorithm keeps on splitting the point cloud in the middle of the axis
// that keeps the point cloud as clustered as possible, which gives a better
// compression rate.
// The number of points is encode by the deviation from the half of the points
// in the smaller half of the two. This results in a better compression rate as
// there are more leading zeros, which is then compressed better by the
// arithmetic encoding.
//
// |PointDiT| is a type representing a point with uint32_t coordinates.
// must provide construction from three uint32_t and operator[].
template <class PointDiT, int compression_level_t>
class IntegerPointsKdTreeEncoder {
typedef IntegerPointsKdTreeEncoderCompressionPolicy<compression_level_t>
Policy;
typedef typename Policy::NumbersEncoder NumbersEncoder;
typedef typename Policy::AxisEncoder AxisEncoder;
typedef typename Policy::HalfEncoder HalfEncoder;
typedef typename Policy::RemainingBitsEncoder RemainingBitsEncoder;
public:
IntegerPointsKdTreeEncoder() : bit_length_(0) {}
// Encodes an integer point cloud given by [begin,end) into buffer.
// |bit_length| gives the highest bit used for all coordinates.
template <class RandomAccessIteratorT>
bool EncodePoints(RandomAccessIteratorT begin, RandomAccessIteratorT end,
const uint32_t &bit_length, EncoderBuffer *buffer);
// Encodes an integer point cloud given by [begin,end) into buffer.
template <class RandomAccessIteratorT>
bool EncodePoints(RandomAccessIteratorT begin, RandomAccessIteratorT end,
EncoderBuffer *buffer) {
return EncodePoints(begin, end, 32, buffer);
}
private:
// For the sack of readability of code, we decided to make this exception
// from the naming scheme.
static constexpr int D = PointTraits<PointDiT>::Dimension();
template <class RandomAccessIteratorT>
uint32_t GetAxis(RandomAccessIteratorT begin, RandomAccessIteratorT end,
const PointDiT &old_base, std::array<uint32_t, D> levels,
uint32_t last_axis);
template <class RandomAccessIteratorT>
void EncodeInternal(RandomAccessIteratorT begin, RandomAccessIteratorT end,
PointDiT old_base, std::array<uint32_t, D> levels,
uint32_t last_axis);
class Splitter {
public:
Splitter(int axis, uint32_t value) : axis_(axis), value_(value) {}
bool operator()(const PointDiT &a) { return a[axis_] < value_; }
private:
int axis_;
uint32_t value_;
};
void EncodeNumber(int nbits, uint32_t value) {
numbers_encoder_.EncodeLeastSignificantBits32(nbits, value);
}
template <class RandomAccessIteratorT>
struct EncodingStatus {
EncodingStatus(
RandomAccessIteratorT begin_, RandomAccessIteratorT end_,
const PointDiT &old_base_,
std::array<uint32_t, PointTraits<PointDiT>::Dimension()> levels_,
uint32_t last_axis_)
: begin(begin_),
end(end_),
old_base(old_base_),
levels(levels_),
last_axis(last_axis_) {
num_remaining_points = end - begin;
}
RandomAccessIteratorT begin;
RandomAccessIteratorT end;
PointDiT old_base;
std::array<uint32_t, D> levels;
uint32_t last_axis;
uint32_t num_remaining_points;
friend bool operator<(const EncodingStatus &l, const EncodingStatus &r) {
return l.num_remaining_points < r.num_remaining_points;
}
};
uint32_t bit_length_;
uint32_t num_points_;
NumbersEncoder numbers_encoder_;
RemainingBitsEncoder remaining_bits_encoder_;
AxisEncoder axis_encoder_;
HalfEncoder half_encoder_;
};
template <class PointDiT, int compression_level_t>
template <class RandomAccessIteratorT>
bool IntegerPointsKdTreeEncoder<PointDiT, compression_level_t>::EncodePoints(
RandomAccessIteratorT begin, RandomAccessIteratorT end,
const uint32_t &bit_length, EncoderBuffer *buffer) {
bit_length_ = bit_length;
num_points_ = end - begin;
buffer->Encode(bit_length_);
buffer->Encode(num_points_);
if (num_points_ == 0)
return true;
numbers_encoder_.StartEncoding();
remaining_bits_encoder_.StartEncoding();
axis_encoder_.StartEncoding();
half_encoder_.StartEncoding();
EncodeInternal(begin, end, PointTraits<PointDiT>::Origin(),
PointTraits<PointDiT>::ZeroArray(), 0);
numbers_encoder_.EndEncoding(buffer);
remaining_bits_encoder_.EndEncoding(buffer);
axis_encoder_.EndEncoding(buffer);
half_encoder_.EndEncoding(buffer);
return true;
}
template <class PointDiT, int compression_level_t>
template <class RandomAccessIteratorT>
uint32_t IntegerPointsKdTreeEncoder<PointDiT, compression_level_t>::GetAxis(
RandomAccessIteratorT begin, RandomAccessIteratorT end,
const PointDiT &old_base, std::array<uint32_t, D> levels,
uint32_t last_axis) {
if (!Policy::select_axis)
return DRACO_INCREMENT_MOD(last_axis, D);
// For many points this function selects the axis that should be used
// for the split by keeping as many points as possible bundled.
// In the best case we do not split the point cloud at all.
// For lower number of points, we simply choose the axis that is refined the
// least so far.
DRACO_DCHECK_EQ(true, end - begin != 0);
uint32_t best_axis = 0;
if (end - begin < 64) {
for (uint32_t axis = 1; axis < D; ++axis) {
if (levels[best_axis] > levels[axis]) {
best_axis = axis;
}
}
} else {
const uint32_t size = (end - begin);
std::array<uint32_t, D> num_remaining_bits =
PointTraits<PointDiT>::ZeroArray();
for (int i = 0; i < D; i++) {
num_remaining_bits[i] = bit_length_ - levels[i];
}
PointDiT split(old_base);
for (int i = 0; i < D; i++) {
if (num_remaining_bits[i])
split[i] += 1 << (num_remaining_bits[i] - 1);
}
std::array<uint32_t, D> deviations = PointTraits<PointDiT>::ZeroArray();
for (auto it = begin; it != end; ++it) {
for (int i = 0; i < D; i++) {
deviations[i] += ((*it)[i] < split[i]);
}
}
for (int i = 0; i < D; i++) {
deviations[i] = std::max(size - deviations[i], deviations[i]);
}
uint32_t max_value = 0;
best_axis = 0;
for (int i = 0; i < D; i++) {
// If axis can be subdivided.
if (num_remaining_bits[i]) {
// Check if this is the better axis.
if (max_value < deviations[i]) {
max_value = deviations[i];
best_axis = i;
}
}
}
axis_encoder_.EncodeLeastSignificantBits32(4, best_axis);
}
return best_axis;
}
template <class PointDiT, int compression_level_t>
template <class RandomAccessIteratorT>
void IntegerPointsKdTreeEncoder<PointDiT, compression_level_t>::EncodeInternal(
RandomAccessIteratorT begin, RandomAccessIteratorT end, PointDiT old_base,
std::array<uint32_t, D> levels, uint32_t last_axis) {
EncodingStatus<RandomAccessIteratorT> init_status(begin, end, old_base,
levels, last_axis);
typename Policy::template QueuingStrategy<
EncodingStatus<RandomAccessIteratorT>>
status_q;
status_q.push(init_status);
while (!status_q.empty()) {
EncodingStatus<RandomAccessIteratorT> status = status_q.front();
status_q.pop();
begin = status.begin;
end = status.end;
old_base = status.old_base;
levels = status.levels;
last_axis = status.last_axis;
const uint32_t axis = GetAxis(begin, end, old_base, levels, last_axis);
const uint32_t level = levels[axis];
const uint32_t num_remaining_points = end - begin;
// If this happens all axis are subdivided to the end.
if ((bit_length_ - level) == 0)
continue;
// Fast encoding of remaining bits if number of points is 1.
// Doing this also for 2 gives a slight additional speed up.
if (num_remaining_points <= 2) {
std::array<uint32_t, D> axes;
axes[0] = axis;
for (int i = 1; i < D; i++) {
axes[i] = DRACO_INCREMENT_MOD(axes[i - 1], D);
}
std::array<uint32_t, D> num_remaining_bits;
for (int i = 0; i < D; i++) {
num_remaining_bits[i] = bit_length_ - levels[axes[i]];
}
for (uint32_t i = 0; i < num_remaining_points; ++i) {
const PointDiT &p = *(begin + i);
for (int j = 0; j < D; j++) {
if (num_remaining_bits[j]) {
remaining_bits_encoder_.EncodeLeastSignificantBits32(
num_remaining_bits[j], p[axes[j]]);
}
}
}
continue;
}
const uint32_t num_remaining_bits = bit_length_ - level;
const uint32_t modifier = 1 << (num_remaining_bits - 1);
PointDiT new_base(old_base);
new_base[axis] += modifier;
const RandomAccessIteratorT split =
std::partition(begin, end, Splitter(axis, new_base[axis]));
DRACO_DCHECK_EQ(true, (end - begin) > 0);
// Encode number of points in first and second half.
const int required_bits = MostSignificantBit(num_remaining_points);
const uint32_t first_half = split - begin;
const uint32_t second_half = end - split;
const bool left = first_half < second_half;
if (first_half != second_half)
half_encoder_.EncodeBit(left);
if (left) {
EncodeNumber(required_bits, num_remaining_points / 2 - first_half);
} else {
EncodeNumber(required_bits, num_remaining_points / 2 - second_half);
}
levels[axis] += 1;
if (split != begin)
status_q.push(EncodingStatus<RandomAccessIteratorT>(
begin, split, old_base, levels, axis));
if (split != end)
status_q.push(EncodingStatus<RandomAccessIteratorT>(split, end, new_base,
levels, axis));
}
}
extern template class IntegerPointsKdTreeEncoder<Point3ui, 0>;
extern template class IntegerPointsKdTreeEncoder<Point3ui, 1>;
extern template class IntegerPointsKdTreeEncoder<Point3ui, 2>;
extern template class IntegerPointsKdTreeEncoder<Point3ui, 3>;
extern template class IntegerPointsKdTreeEncoder<Point3ui, 4>;
extern template class IntegerPointsKdTreeEncoder<Point3ui, 5>;
extern template class IntegerPointsKdTreeEncoder<Point3ui, 6>;
extern template class IntegerPointsKdTreeEncoder<Point3ui, 7>;
extern template class IntegerPointsKdTreeEncoder<Point3ui, 8>;
extern template class IntegerPointsKdTreeEncoder<Point3ui, 9>;
extern template class IntegerPointsKdTreeEncoder<Point3ui, 10>;
} // namespace draco
#endif // DRACO_COMPRESSION_POINT_CLOUD_ALGORITHMS_INTEGER_POINTS_KD_TREE_ENCODER_H_