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Refactor the vector tile constants

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This commit is contained in:
Patrick Niklaus 2016-04-14 16:33:23 +02:00
parent 324f1739e4
commit 6979763292
2 changed files with 71 additions and 32 deletions
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37
include/util/vector_tile.hpp Normal file
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@ -0,0 +1,37 @@
#ifndef OSRM_UTIL_VECTOR_TILE_HPP
#define OSRM_UTIL_VECTOR_TILE_HPP
#include <cstdint>
namespace osrm
{
namespace util
{
namespace vector_tile
{
const constexpr std::uint32_t LAYER_TAG = 3;
const constexpr std::uint32_t NAME_TAG = 1;
const constexpr std::uint32_t VERSION_TAG = 15;
const constexpr std::uint32_t EXTEND_TAG = 5;
const constexpr std::uint32_t FEATURE_TAG = 2;
const constexpr std::uint32_t GEOMETRY_TAG = 3;
const constexpr std::uint32_t VARIANT_TAG = 4;
const constexpr std::uint32_t KEY_TAG = 3;
const constexpr std::uint32_t ID_TAG = 1;
const constexpr std::uint32_t GEOMETRY_TYPE_LINE = 2;
const constexpr std::uint32_t FEATURE_ATTRIBUTES_TAG = 2;
const constexpr std::uint32_t FEATURE_GEOMETRIES_TAG = 4;
const constexpr std::uint32_t VARIANT_TYPE_UINT32 = 5;
const constexpr std::uint32_t VARIANT_TYPE_BOOL = 7;
const constexpr std::uint32_t VARIANT_TYPE_STRING = 1;
const constexpr std::uint32_t VARIANT_TYPE_DOUBLE = 3;
// Vector tiles are 4096 virtual pixels on each side
const constexpr double EXTENT = 4096.0;
const constexpr double BUFFER = 128.0;
}
}
}
#endif

66
src/engine/plugins/tile.cpp
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@ -3,6 +3,7 @@
#include "util/coordinate_calculation.hpp"
#include "util/web_mercator.hpp"
#include "util/vector_tile.hpp"
#include <boost/geometry.hpp>
#include <boost/geometry/geometries/point_xy.hpp>
@ -27,10 +28,6 @@ namespace plugins
{
namespace detail
{
// Vector tiles are 4096 virtual pixels on each side
const constexpr double VECTOR_TILE_EXTENT = 4096.0;
const constexpr double VECTOR_TILE_BUFFER = 128.0;
// Simple container class for WGS84 coordinates
template <typename T> struct Point final
{
@ -78,9 +75,9 @@ typedef boost::geometry::model::point<double, 2, boost::geometry::cs::cartesian>
typedef boost::geometry::model::linestring<point_t> linestring_t;
typedef boost::geometry::model::box<point_t> box_t;
typedef boost::geometry::model::multi_linestring<linestring_t> multi_linestring_t;
const static box_t clip_box(point_t(-detail::VECTOR_TILE_BUFFER, -detail::VECTOR_TILE_BUFFER),
point_t(detail::VECTOR_TILE_EXTENT + detail::VECTOR_TILE_BUFFER,
detail::VECTOR_TILE_EXTENT + detail::VECTOR_TILE_BUFFER));
const static box_t clip_box(point_t(-util::vector_tile::BUFFER, -util::vector_tile::BUFFER),
point_t(util::vector_tile::EXTENT + util::vector_tile::BUFFER,
util::vector_tile::EXTENT + util::vector_tile::BUFFER));
// from mapnik-vector-tile
// Encodes a linestring using protobuf zigzag encoding
@ -136,10 +133,10 @@ FixedLine coordinatesToTileLine(const util::Coordinate start,
// convert lon/lat to tile coordinates
const auto px = std::round(
((px_merc - tile_bbox.minx) * util::web_mercator::TILE_SIZE / tile_bbox.width()) *
detail::VECTOR_TILE_EXTENT / util::web_mercator::TILE_SIZE);
util::vector_tile::EXTENT / util::web_mercator::TILE_SIZE);
const auto py = std::round(
((tile_bbox.maxy - py_merc) * util::web_mercator::TILE_SIZE / tile_bbox.height()) *
detail::VECTOR_TILE_EXTENT / util::web_mercator::TILE_SIZE);
util::vector_tile::EXTENT / util::web_mercator::TILE_SIZE);
boost::geometry::append(unclipped_line, point_t(px, py));
}
@ -254,15 +251,15 @@ Status TilePlugin::HandleRequest(const api::TileParameters &parameters, std::str
protozero::pbf_writer tile_writer{pbf_buffer};
{
// Add a layer object to the PBF stream. 3=='layer' from the vector tile spec (2.1)
protozero::pbf_writer layer_writer(tile_writer, 3);
protozero::pbf_writer layer_writer(tile_writer, util::vector_tile::LAYER_TAG);
// TODO: don't write a layer if there are no features
layer_writer.add_uint32(15, 2); // version
layer_writer.add_uint32(util::vector_tile::VERSION_TAG, 2); // version
// Field 1 is the "layer name" field, it's a string
layer_writer.add_string(1, "speeds"); // name
layer_writer.add_string(util::vector_tile::NAME_TAG, "speeds"); // name
// Field 5 is the tile extent. It's a uint32 and should be set to 4096
// for normal vector tiles.
layer_writer.add_uint32(5, 4096); // extent
layer_writer.add_uint32(util::vector_tile::EXTEND_TAG, util::vector_tile::EXTENT); // extent
// Begin the layer features block
{
@ -328,11 +325,13 @@ Status TilePlugin::HandleRequest(const api::TileParameters &parameters, std::str
// is_small
// boolean. We onl serve up speeds from 0-139, so all we do is save the
// first
protozero::pbf_writer feature_writer(layer_writer, 2);
protozero::pbf_writer feature_writer(layer_writer,
util::vector_tile::FEATURE_TAG);
// Field 3 is the "geometry type" field. Value 2 is "line"
feature_writer.add_enum(3, 2); // geometry type
feature_writer.add_enum(util::vector_tile::GEOMETRY_TAG,
util::vector_tile::GEOMETRY_TYPE_LINE); // geometry type
// Field 1 for the feature is the "id" field.
feature_writer.add_uint64(1, id++); // id
feature_writer.add_uint64(util::vector_tile::ID_TAG, id++); // id
{
// When adding attributes to a feature, we have to write
// pairs of numbers. The first value is the index in the
@ -341,7 +340,8 @@ Status TilePlugin::HandleRequest(const api::TileParameters &parameters, std::str
// not writing the actual speed or bool value here, we're saving
// an index into the "values" array. This means many features
// can share the same value data, leading to smaller tiles.
protozero::packed_field_uint32 field(feature_writer, 2);
protozero::packed_field_uint32 field(
feature_writer, util::vector_tile::FEATURE_ATTRIBUTES_TAG);
field.add_element(0); // "speed" tag key offset
field.add_element(
@ -358,7 +358,8 @@ Status TilePlugin::HandleRequest(const api::TileParameters &parameters, std::str
{
// Encode the geometry for the feature
protozero::packed_field_uint32 geometry(feature_writer, 4);
protozero::packed_field_uint32 geometry(
feature_writer, util::vector_tile::FEATURE_GEOMETRIES_TAG);
encodeLinestring(tile_line, geometry, start_x, start_y);
}
};
@ -405,10 +406,10 @@ Status TilePlugin::HandleRequest(const api::TileParameters &parameters, std::str
// Field id 3 is the "keys" attribute
// We need two "key" fields, these are referred to with 0 and 1 (their array indexes)
// earlier
layer_writer.add_string(3, "speed");
layer_writer.add_string(3, "is_small");
layer_writer.add_string(3, "datasource");
layer_writer.add_string(3, "duration");
layer_writer.add_string(util::vector_tile::KEY_TAG, "speed");
layer_writer.add_string(util::vector_tile::KEY_TAG, "is_small");
layer_writer.add_string(util::vector_tile::KEY_TAG, "datasource");
layer_writer.add_string(util::vector_tile::KEY_TAG, "duration");
// Now, we write out the possible speed value arrays and possible is_tiny
// values. Field type 4 is the "values" field. It's a variable type field,
@ -416,35 +417,36 @@ Status TilePlugin::HandleRequest(const api::TileParameters &parameters, std::str
for (std::size_t i = 0; i < 128; i++)
{
// Writing field type 4 == variant type
protozero::pbf_writer values_writer(layer_writer, 4);
protozero::pbf_writer values_writer(layer_writer, util::vector_tile::VARIANT_TAG);
// Attribute value 5 == uin64 type
values_writer.add_uint64(5, i);
values_writer.add_uint64(util::vector_tile::VARIANT_TYPE_UINT32, i);
}
{
protozero::pbf_writer values_writer(layer_writer, 4);
protozero::pbf_writer values_writer(layer_writer, util::vector_tile::VARIANT_TAG);
// Attribute value 7 == bool type
values_writer.add_bool(7, true);
values_writer.add_bool(util::vector_tile::VARIANT_TYPE_BOOL, true);
}
{
protozero::pbf_writer values_writer(layer_writer, 4);
protozero::pbf_writer values_writer(layer_writer, util::vector_tile::VARIANT_TAG);
// Attribute value 7 == bool type
values_writer.add_bool(7, false);
values_writer.add_bool(util::vector_tile::VARIANT_TYPE_BOOL, false);
}
for (std::size_t i = 0; i <= max_datasource_id; i++)
{
// Writing field type 4 == variant type
protozero::pbf_writer values_writer(layer_writer, 4);
protozero::pbf_writer values_writer(layer_writer, util::vector_tile::VARIANT_TAG);
// Attribute value 1 == string type
values_writer.add_string(1, facade.GetDatasourceName(i));
values_writer.add_string(util::vector_tile::VARIANT_TYPE_STRING,
facade.GetDatasourceName(i));
}
for (auto weight : used_weights)
{
// Writing field type 4 == variant type
protozero::pbf_writer values_writer(layer_writer, 4);
protozero::pbf_writer values_writer(layer_writer, util::vector_tile::VARIANT_TAG);
// Attribute value 2 == float type
// Durations come out of OSRM in integer deciseconds, so we convert them
// to seconds with a simple /10 for display
values_writer.add_double(3, weight / 10.);
values_writer.add_double(util::vector_tile::VARIANT_TYPE_DOUBLE, weight / 10.);
}
}