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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.
//
#include "draco/compression/attributes/sequential_integer_attribute_encoder.h"
#include "draco/compression/attributes/prediction_schemes/prediction_scheme_encoder_factory.h"
#include "draco/compression/attributes/prediction_schemes/prediction_scheme_wrap_encoding_transform.h"
#include "draco/compression/entropy/symbol_encoding.h"
#include "draco/core/bit_utils.h"
namespace draco {
SequentialIntegerAttributeEncoder::SequentialIntegerAttributeEncoder() {}
bool SequentialIntegerAttributeEncoder::Init(PointCloudEncoder *encoder,
int attribute_id) {
if (!SequentialAttributeEncoder::Init(encoder, attribute_id)) {
return false;
}
if (GetUniqueId() == SEQUENTIAL_ATTRIBUTE_ENCODER_INTEGER) {
// When encoding integers, this encoder currently works only for integer
// attributes up to 32 bits.
switch (attribute()->data_type()) {
case DT_INT8:
case DT_UINT8:
case DT_INT16:
case DT_UINT16:
case DT_INT32:
case DT_UINT32:
break;
default:
return false;
}
}
// Init prediction scheme.
const PredictionSchemeMethod prediction_scheme_method =
GetPredictionMethodFromOptions(attribute_id, *encoder->options());
prediction_scheme_ = CreateIntPredictionScheme(prediction_scheme_method);
if (prediction_scheme_ && !InitPredictionScheme(prediction_scheme_.get())) {
prediction_scheme_ = nullptr;
}
return true;
}
bool SequentialIntegerAttributeEncoder::TransformAttributeToPortableFormat(
const std::vector<PointIndex> &point_ids) {
if (encoder()) {
if (!PrepareValues(point_ids, encoder()->point_cloud()->num_points())) {
return false;
}
} else {
if (!PrepareValues(point_ids, 0)) {
return false;
}
}
// Update point to attribute mapping with the portable attribute if the
// attribute is a parent attribute (for now, we can skip it otherwise).
if (is_parent_encoder()) {
// First create map between original attribute value indices and new ones
// (determined by the encoding order).
const PointAttribute *const orig_att = attribute();
PointAttribute *const portable_att = portable_attribute();
IndexTypeVector<AttributeValueIndex, AttributeValueIndex>
value_to_value_map(orig_att->size());
for (int i = 0; i < point_ids.size(); ++i) {
value_to_value_map[orig_att->mapped_index(point_ids[i])] =
AttributeValueIndex(i);
}
if (portable_att->is_mapping_identity()) {
portable_att->SetExplicitMapping(encoder()->point_cloud()->num_points());
}
// Go over all points of the original attribute and update the mapping in
// the portable attribute.
for (PointIndex i(0); i < encoder()->point_cloud()->num_points(); ++i) {
portable_att->SetPointMapEntry(
i, value_to_value_map[orig_att->mapped_index(i)]);
}
}
return true;
}
std::unique_ptr<PredictionSchemeTypedEncoderInterface<int32_t>>
SequentialIntegerAttributeEncoder::CreateIntPredictionScheme(
PredictionSchemeMethod method) {
return CreatePredictionSchemeForEncoder<
int32_t, PredictionSchemeWrapEncodingTransform<int32_t>>(
method, attribute_id(), encoder());
}
bool SequentialIntegerAttributeEncoder::EncodeValues(
const std::vector<PointIndex> &point_ids, EncoderBuffer *out_buffer) {
// Initialize general quantization data.
const PointAttribute *const attrib = attribute();
if (attrib->size() == 0) {
return true;
}
int8_t prediction_scheme_method = PREDICTION_NONE;
if (prediction_scheme_) {
if (!SetPredictionSchemeParentAttributes(prediction_scheme_.get())) {
return false;
}
prediction_scheme_method =
static_cast<int8_t>(prediction_scheme_->GetPredictionMethod());
}
out_buffer->Encode(prediction_scheme_method);
if (prediction_scheme_) {
out_buffer->Encode(
static_cast<int8_t>(prediction_scheme_->GetTransformType()));
}
const int num_components = portable_attribute()->num_components();
const int num_values =
static_cast<int>(num_components * portable_attribute()->size());
const int32_t *const portable_attribute_data = GetPortableAttributeData();
// We need to keep the portable data intact, but several encoding steps can
// result in changes of this data, e.g., by applying prediction schemes that
// change the data in place. To preserve the portable data we store and
// process all encoded data in a separate array.
std::vector<int32_t> encoded_data(num_values);
// All integer values are initialized. Process them using the prediction
// scheme if we have one.
if (prediction_scheme_) {
prediction_scheme_->ComputeCorrectionValues(
portable_attribute_data, &encoded_data[0], num_values, num_components,
point_ids.data());
}
if (prediction_scheme_ == nullptr ||
!prediction_scheme_->AreCorrectionsPositive()) {
const int32_t *const input =
prediction_scheme_ ? encoded_data.data() : portable_attribute_data;
ConvertSignedIntsToSymbols(input, num_values,
reinterpret_cast<uint32_t *>(&encoded_data[0]));
}
if (encoder() == nullptr || encoder()->options()->GetGlobalBool(
"use_built_in_attribute_compression", true)) {
out_buffer->Encode(static_cast<uint8_t>(1));
Options symbol_encoding_options;
if (encoder() != nullptr) {
SetSymbolEncodingCompressionLevel(&symbol_encoding_options,
10 - encoder()->options()->GetSpeed());
}
if (!EncodeSymbols(reinterpret_cast<uint32_t *>(encoded_data.data()),
static_cast<int>(point_ids.size()) * num_components,
num_components, &symbol_encoding_options, out_buffer)) {
return false;
}
} else {
// No compression. Just store the raw integer values, using the number of
// bytes as needed.
// To compute the maximum bit-length, first OR all values.
uint32_t masked_value = 0;
for (uint32_t i = 0; i < static_cast<uint32_t>(num_values); ++i) {
masked_value |= encoded_data[i];
}
// Compute the msb of the ORed value.
int value_msb_pos = 0;
if (masked_value != 0) {
value_msb_pos = MostSignificantBit(masked_value);
}
const int num_bytes = 1 + value_msb_pos / 8;
out_buffer->Encode(static_cast<uint8_t>(0));
out_buffer->Encode(static_cast<uint8_t>(num_bytes));
if (num_bytes == DataTypeLength(DT_INT32)) {
out_buffer->Encode(encoded_data.data(), sizeof(int32_t) * num_values);
} else {
for (uint32_t i = 0; i < static_cast<uint32_t>(num_values); ++i) {
out_buffer->Encode(encoded_data.data() + i, num_bytes);
}
}
}
if (prediction_scheme_) {
prediction_scheme_->EncodePredictionData(out_buffer);
}
return true;
}
bool SequentialIntegerAttributeEncoder::PrepareValues(
const std::vector<PointIndex> &point_ids, int num_points) {
// Convert all values to int32_t format.
const PointAttribute *const attrib = attribute();
const int num_components = attrib->num_components();
const int num_entries = static_cast<int>(point_ids.size());
PreparePortableAttribute(num_entries, num_components, num_points);
int32_t dst_index = 0;
int32_t *const portable_attribute_data = GetPortableAttributeData();
for (PointIndex pi : point_ids) {
const AttributeValueIndex att_id = attrib->mapped_index(pi);
if (!attrib->ConvertValue<int32_t>(att_id,
portable_attribute_data + dst_index)) {
return false;
}
dst_index += num_components;
}
return true;
}
void SequentialIntegerAttributeEncoder::PreparePortableAttribute(
int num_entries, int num_components, int num_points) {
GeometryAttribute va;
va.Init(attribute()->attribute_type(), nullptr, num_components, DT_INT32,
false, num_components * DataTypeLength(DT_INT32), 0);
std::unique_ptr<PointAttribute> port_att(new PointAttribute(va));
port_att->Reset(num_entries);
SetPortableAttribute(std::move(port_att));
if (num_points) {
portable_attribute()->SetExplicitMapping(num_points);
}
}
} // namespace draco
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