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OpenSpace/modules/space/rendering/renderablesatellites.cpp
Alexander Bock ac867c4e9e Some rudimentary cleanup
2019-08-19 11:35:48 +02:00

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/****************************************************************************************
* *
* OpenSpace *
* *
* Copyright (c) 2014-2018 *
* *
* Permission is hereby granted, free of charge, to any person obtaining a copy of this *
* software and associated documentation files (the "Software"), to deal in the Software *
* without restriction, including without limitation the rights to use, copy, modify, *
* merge, publish, distribute, sublicense, and/or sell copies of the Software, and to *
* permit persons to whom the Software is furnished to do so, subject to the following *
* conditions: *
* *
* The above copyright notice and this permission notice shall be included in all copies *
* or substantial portions of the Software. *
* *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, *
* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A *
* PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT *
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF *
* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE *
* OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
****************************************************************************************/
#include <modules/space/rendering/renderablesatellites.h>
#include <modules/space/translation/keplertranslation.h>
#include <modules/space/translation/tletranslation.h>
#include <modules/space/spacemodule.h>
#include <openspace/engine/openspaceengine.h>
#include <openspace/rendering/renderengine.h>
#include <openspace/engine/globals.h>
#include <openspace/documentation/documentation.h>
#include <openspace/documentation/verifier.h>
#include <openspace/util/time.h>
#include <openspace/util/updatestructures.h>
#include <ghoul/filesystem/filesystem.h>
#include <ghoul/filesystem/file.h>
#include <ghoul/misc/csvreader.h>
#include <ghoul/opengl/programobject.h>
#include <ghoul/logging/logmanager.h>
#include <chrono>
#include <math.h>
#include <fstream>
#include <vector>
namespace {
constexpr const char* ProgramName = "RenderableSatellites";
constexpr const char* _loggerCat = "Satellites";
static const openspace::properties::Property::PropertyInfo PathInfo = {
"Path",
"Path",
"The file path to the TLE file to read"
};
static const openspace::properties::Property::PropertyInfo SegmentsInfo = {
"Segments",
"Segments",
"The number of segments to use for each orbit ellipse"
};
constexpr openspace::properties::Property::PropertyInfo LineWidthInfo = {
"LineWidth",
"Line Width",
"This value specifies the line width of the trail if the selected rendering "
"method includes lines. If the rendering mode is set to Points, this value is "
"ignored."
};
constexpr openspace::properties::Property::PropertyInfo FadeInfo = {
"Fade",
"Line fade",
"The fading factor that is applied to the trail if the 'EnableFade' value is "
"'true'. If it is 'false', this setting has no effect. The higher the number, "
"the less fading is applied."
};
constexpr openspace::properties::Property::PropertyInfo LineColorInfo = {
"Color",
"Color",
"This value determines the RGB main color for the lines and points of the trail."
};
constexpr const char* KeyFile = "Path";
constexpr const char* KeyLineNum = "LineNumber";
}
namespace openspace {
// The list of leap years only goes until 2056 as we need to touch this file then
// again anyway ;)
const std::vector<int> LeapYears = {
1956, 1960, 1964, 1968, 1972, 1976, 1980, 1984, 1988, 1992, 1996,
2000, 2004, 2008, 2012, 2016, 2020, 2024, 2028, 2032, 2036, 2040,
2044, 2048, 2052, 2056
};
// Count the number of full days since the beginning of 2000 to the beginning of
// the parameter 'year'
int countDays(int year) {
// Find the position of the current year in the vector, the difference
// between its position and the position of 2000 (for J2000) gives the
// number of leap years
constexpr const int Epoch = 2000;
constexpr const int DaysRegularYear = 365;
constexpr const int DaysLeapYear = 366;
if (year == Epoch) {
return 0;
}
// Get the position of the most recent leap year
const auto lb = std::lower_bound(LeapYears.begin(), LeapYears.end(), year);
// Get the position of the epoch
const auto y2000 = std::find(LeapYears.begin(), LeapYears.end(), Epoch);
// The distance between the two iterators gives us the number of leap years
const int nLeapYears = static_cast<int>(std::abs(std::distance(y2000, lb)));
const int nYears = std::abs(year - Epoch);
const int nRegularYears = nYears - nLeapYears;
// Get the total number of days as the sum of leap years + non leap years
const int result = nRegularYears * DaysRegularYear + nLeapYears * DaysLeapYear;
return result;
}
// Returns the number of leap seconds that lie between the {year, dayOfYear}
// time point and { 2000, 1 }
int countLeapSeconds(int year, int dayOfYear) {
// Find the position of the current year in the vector; its position in
// the vector gives the number of leap seconds
struct LeapSecond {
int year;
int dayOfYear;
bool operator<(const LeapSecond& rhs) const {
return std::tie(year, dayOfYear) < std::tie(rhs.year, rhs.dayOfYear);
}
};
const LeapSecond Epoch = { 2000, 1 };
// List taken from: https://www.ietf.org/timezones/data/leap-seconds.list
static const std::vector<LeapSecond> LeapSeconds = {
{ 1972, 1 },
{ 1972, 183 },
{ 1973, 1 },
{ 1974, 1 },
{ 1975, 1 },
{ 1976, 1 },
{ 1977, 1 },
{ 1978, 1 },
{ 1979, 1 },
{ 1980, 1 },
{ 1981, 182 },
{ 1982, 182 },
{ 1983, 182 },
{ 1985, 182 },
{ 1988, 1 },
{ 1990, 1 },
{ 1991, 1 },
{ 1992, 183 },
{ 1993, 182 },
{ 1994, 182 },
{ 1996, 1 },
{ 1997, 182 },
{ 1999, 1 },
{ 2006, 1 },
{ 2009, 1 },
{ 2012, 183 },
{ 2015, 182 },
{ 2017, 1 }
};
// Get the position of the last leap second before the desired date
LeapSecond date { year, dayOfYear };
const auto it = std::lower_bound(LeapSeconds.begin(), LeapSeconds.end(), date);
// Get the position of the Epoch
const auto y2000 = std::lower_bound(
LeapSeconds.begin(),
LeapSeconds.end(),
Epoch
);
// The distance between the two iterators gives us the number of leap years
const int nLeapSeconds = static_cast<int>(std::abs(std::distance(y2000, it)));
return nLeapSeconds;
}
double calculateSemiMajorAxis(double meanMotion) {
constexpr const double GravitationalConstant = 6.6740831e-11;
constexpr const double MassEarth = 5.9721986e24;
constexpr const double muEarth = GravitationalConstant * MassEarth;
// Use Kepler's 3rd law to calculate semimajor axis
// a^3 / P^2 = mu / (2pi)^2
// <=> a = ((mu * P^2) / (2pi^2))^(1/3)
// with a = semimajor axis
// P = period in seconds
// mu = G*M_earth
double period = std::chrono::seconds(std::chrono::hours(24)).count() / meanMotion;
const double pisq = glm::pi<double>() * glm::pi<double>();
double semiMajorAxis = pow((muEarth * period*period) / (4 * pisq), 1.0 / 3.0);
// We need the semi major axis in km instead of m
return semiMajorAxis / 1000.0;
}
double epochFromSubstring(const std::string& epochString) {
// The epochString is in the form:
// YYDDD.DDDDDDDD
// With YY being the last two years of the launch epoch, the first DDD the day
// of the year and the remaning a fractional part of the day
// The main overview of this function:
// 1. Reconstruct the full year from the YY part
// 2. Calculate the number of seconds since the beginning of the year
// 2.a Get the number of full days since the beginning of the year
// 2.b If the year is a leap year, modify the number of days
// 3. Convert the number of days to a number of seconds
// 4. Get the number of leap seconds since January 1st, 2000 and remove them
// 5. Adjust for the fact the epoch starts on 1st Januaray at 12:00:00, not
// midnight
// According to https://celestrak.com/columns/v04n03/
// Apparently, US Space Command sees no need to change the two-line element
// set format yet since no artificial earth satellites existed prior to 1957.
// By their reasoning, two-digit years from 57-99 correspond to 1957-1999 and
// those from 00-56 correspond to 2000-2056. We'll see each other again in 2057!
// 1. Get the full year
std::string yearPrefix = [y = epochString.substr(0, 2)](){
int year = std::atoi(y.c_str());
return year >= 57 ? "19" : "20";
}();
const int year = std::atoi((yearPrefix + epochString.substr(0, 2)).c_str());
const int daysSince2000 = countDays(year);
// 2.
// 2.a
double daysInYear = std::atof(epochString.substr(2).c_str());
// 2.b
const bool isInLeapYear = std::find(
LeapYears.begin(),
LeapYears.end(),
year
) != LeapYears.end();
if (isInLeapYear && daysInYear >= 60) {
// We are in a leap year, so we have an effective day more if we are
// beyond the end of february (= 31+29 days)
--daysInYear;
}
// 3
using namespace std::chrono;
const int SecondsPerDay = static_cast<int>(seconds(hours(24)).count());
//Need to subtract 1 from daysInYear since it is not a zero-based count
const double nSecondsSince2000 = (daysSince2000 + daysInYear - 1) * SecondsPerDay;
// 4
// We need to remove additional leap seconds past 2000 and add them prior to
// 2000 to sync up the time zones
const double nLeapSecondsOffset = -countLeapSeconds(
year,
static_cast<int>(std::floor(daysInYear))
);
// 5
const double nSecondsEpochOffset = static_cast<double>(
seconds(hours(12)).count()
);
// Combine all of the values
const double epoch = nSecondsSince2000 + nLeapSecondsOffset - nSecondsEpochOffset;
return epoch;
}
documentation::Documentation RenderableSatellites::Documentation() {
using namespace documentation;
return {
"RenderableSatellites",
"space_renderable_satellites",
{
{
SegmentsInfo.identifier,
new DoubleVerifier,
Optional::No,
SegmentsInfo.description
},
{
PathInfo.identifier,
new StringVerifier,
Optional::No,
PathInfo.description
},
{
LineWidthInfo.identifier,
new DoubleVerifier,
Optional::Yes,
LineWidthInfo.description
},
{
FadeInfo.identifier,
new DoubleVerifier,
Optional::Yes,
FadeInfo.description
},
{
LineColorInfo.identifier,
new DoubleVector3Verifier,
Optional::No,
LineColorInfo.description
}
}
};
}
RenderableSatellites::RenderableSatellites(const ghoul::Dictionary& dictionary)
: Renderable(dictionary)
, _path(PathInfo)
, _nSegments(SegmentsInfo)
, _lineFade(FadeInfo)
{
documentation::testSpecificationAndThrow(
Documentation(),
dictionary,
"RenderableSatellites"
);
_path = dictionary.value<std::string>(PathInfo.identifier);
_nSegments = static_cast<int>(dictionary.value<double>(SegmentsInfo.identifier));
_lineFade = static_cast<float>(dictionary.value<double>(FadeInfo.identifier));
if (dictionary.hasKeyAndValue<glm::vec3>(LineColorInfo.identifier)) {
_appearance.lineColor = dictionary.value<glm::vec3>(LineColorInfo.identifier);
}
addPropertySubOwner(_appearance);
addProperty(_path);
addProperty(_nSegments);
addProperty(_lineFade);
}
void RenderableSatellites::readTLEFile(const std::string& filename) {
if (!FileSys.fileExists(filename)) {
throw ghoul::RuntimeError(fmt::format(
"Satellite TLE file {} does not exist.", filename
));
}
std::ifstream file;
file.exceptions(std::ifstream::failbit | std::ifstream::badbit);
file.open(filename);
std::streamoff numberOfLines = std::count(std::istreambuf_iterator<char>(file),
std::istreambuf_iterator<char>(), '\n' );
file.seekg(std::ios_base::beg); // reset iterator to beginning of file
// 3 because a TLE has 3 lines per element/ object.
std::streamoff numberOfObjects = numberOfLines / 3;
std::string line = "-";
for (std::streamoff i = 0; i < numberOfObjects; i++) {
std::getline(file, line); // get rid of title
KeplerParameters keplerElements;
std::getline(file, line);
if (line[0] == '1') {
// First line
// Field Columns Content
// 1 01-01 Line number
// 2 03-07 Satellite number
// 3 08-08 Classification (U = Unclassified)
// 4 10-11 International Designator (Last two digits of launch year)
// 5 12-14 International Designator (Launch number of the year)
// 6 15-17 International Designator(piece of the launch) A
// 7 19-20 Epoch Year(last two digits of year)
// 8 21-32 Epoch(day of the year and fractional portion of the day)
// 9 34-43 First Time Derivative of the Mean Motion divided by two
// 10 45-52 Second Time Derivative of Mean Motion divided by six
// 11 54-61 BSTAR drag term(decimal point assumed)[10] - 11606 - 4
// 12 63-63 The "Ephemeris type"
// 13 65-68 Element set number.Incremented when a new TLE is generated
// 14 69-69 Checksum (modulo 10)
keplerElements.epoch = epochFromSubstring(line.substr(18, 14));
}
else {
throw ghoul::RuntimeError(fmt::format(
"File {} entry {} does not have '1' header", filename, i + 1
));
}
std::getline(file, line);
if (line[0] == '2') {
// Second line
// Field Columns Content
// 1 01-01 Line number
// 2 03-07 Satellite number
// 3 09-16 Inclination (degrees)
// 4 18-25 Right ascension of the ascending node (degrees)
// 5 27-33 Eccentricity (decimal point assumed)
// 6 35-42 Argument of perigee (degrees)
// 7 44-51 Mean Anomaly (degrees)
// 8 53-63 Mean Motion (revolutions per day)
// 9 64-68 Revolution number at epoch (revolutions)
// 10 69-69 Checksum (modulo 10)
std::stringstream stream;
stream.exceptions(std::ios::failbit);
// Get inclination
stream.str(line.substr(8, 8));
stream >> keplerElements.inclination;
stream.clear();
// Get Right ascension of the ascending node
stream.str(line.substr(17, 8));
stream >> keplerElements.ascendingNode;
stream.clear();
// Get Eccentricity
stream.str("0." + line.substr(26, 7));
stream >> keplerElements.eccentricity;
stream.clear();
// Get argument of periapsis
stream.str(line.substr(34, 8));
stream >> keplerElements.argumentOfPeriapsis;
stream.clear();
// Get mean anomaly
stream.str(line.substr(43, 8));
stream >> keplerElements.meanAnomaly;
stream.clear();
// Get mean motion
stream.str(line.substr(52, 11));
stream >> keplerElements.meanMotion;
}
else {
throw ghoul::RuntimeError(fmt::format(
"File {} entry {} does not have '2' header", filename, i + 1
));
}
// Calculate the semi major axis based on the mean motion using kepler's laws
keplerElements.semiMajorAxis = calculateSemiMajorAxis(keplerElements.meanMotion);
using namespace std::chrono;
double period = seconds(hours(24)).count() / keplerElements.meanMotion;
keplerElements.period = period;
_TLEData.push_back(keplerElements);
}
file.close();
}
void RenderableSatellites::initializeGL() {
glGenVertexArrays(1, &_vertexArray);
glGenBuffers(1, &_vertexBuffer);
_programObject = SpaceModule::ProgramObjectManager.request(
ProgramName,
[]() -> std::unique_ptr<ghoul::opengl::ProgramObject> {
return global::renderEngine.buildRenderProgram(
ProgramName,
absPath("${MODULE_SPACE}/shaders/debrisViz_vs.glsl"),
absPath("${MODULE_SPACE}/shaders/debrisViz_fs.glsl")
);
}
);
_uniformCache.modelView = _programObject->uniformLocation("modelViewTransform");
_uniformCache.projection = _programObject->uniformLocation("projectionTransform");
_uniformCache.lineFade = _programObject->uniformLocation("lineFade");
_uniformCache.inGameTime = _programObject->uniformLocation("inGameTime");
_uniformCache.color = _programObject->uniformLocation("color");
_uniformCache.opacity = _programObject->uniformLocation("opacity");
updateBuffers();
setRenderBin(Renderable::RenderBin::Overlay);
}
void RenderableSatellites::deinitializeGL() {
glDeleteBuffers(1, &_vertexBuffer);
glDeleteVertexArrays(1, &_vertexArray);
SpaceModule::ProgramObjectManager.release(
ProgramName,
[](ghoul::opengl::ProgramObject* p) {
global::renderEngine.removeRenderProgram(p);
}
);
_programObject = nullptr;
}
bool RenderableSatellites::isReady() const {
return _programObject != nullptr;
}
void RenderableSatellites::render(const RenderData& data, RendererTasks&) {
if (_TLEData.empty())
return;
_programObject->activate();
_programObject->setUniform(_uniformCache.opacity, _opacity);
_programObject->setUniform(_uniformCache.inGameTime, data.time.j2000Seconds());
glm::dmat4 modelTransform =
glm::translate(glm::dmat4(1.0), data.modelTransform.translation) *
glm::dmat4(data.modelTransform.rotation) *
glm::scale(glm::dmat4(1.0), glm::dvec3(data.modelTransform.scale));
_programObject->setUniform(
_uniformCache.modelView,
data.camera.combinedViewMatrix() * modelTransform
);
_programObject->setUniform(_uniformCache.projection, data.camera.projectionMatrix());
_programObject->setUniform(_uniformCache.color, _appearance.lineColor);
_programObject->setUniform(_uniformCache.lineFade, _appearance.lineFade);
glLineWidth(_appearance.lineWidth);
const size_t nrOrbits = _TLEData.size();
gl::GLint vertices = 0;
//glDepthMask(false);
//glBlendFunc(GL_SRC_ALPHA, GL_ONE)
glBindVertexArray(_vertexArray);
for (size_t i = 0; i < nrOrbits; ++i) {
glDrawArrays(GL_LINE_STRIP, vertices, _nSegments + 1);
vertices = vertices + _nSegments + 1;
}
glBindVertexArray(0);
_programObject->deactivate();
}
void RenderableSatellites::updateBuffers() {
readTLEFile(_path);
const size_t nVerticesPerOrbit = _nSegments + 1;
_vertexBufferData.resize(_TLEData.size() * nVerticesPerOrbit);
size_t orbitindex = 0;
for (const auto& orbit : _TLEData) {
_keplerTranslator.setKeplerElements(
orbit.eccentricity,
orbit.semiMajorAxis,
orbit.inclination,
orbit.ascendingNode,
orbit.argumentOfPeriapsis,
orbit.meanAnomaly,
orbit.period,
orbit.epoch
);
for (size_t i=0 ; i < nVerticesPerOrbit; ++i) {
size_t index = orbitindex * nVerticesPerOrbit + i;
double timeOffset = orbit.period *
static_cast<double>(i)/ static_cast<double>(_nSegments);
glm::dvec3 position = _keplerTranslator.position({
{},
Time(timeOffset + orbit.epoch),
Time(0.0),
false
});
double positionX = position.x;
double positionY = position.y;
double positionZ = position.z;
_vertexBufferData[index].x = static_cast<float>(positionX);
_vertexBufferData[index].y = static_cast<float>(positionY);
_vertexBufferData[index].z = static_cast<float>(positionZ);
_vertexBufferData[index].time = static_cast<float>(timeOffset);
_vertexBufferData[index].epoch = orbit.epoch;
_vertexBufferData[index].period = orbit.period;
}
++orbitindex;
}
glBindVertexArray(_vertexArray);
glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer);
glBufferData(
GL_ARRAY_BUFFER,
_vertexBufferData.size() * sizeof(TrailVBOLayout),
_vertexBufferData.data(),
GL_STATIC_DRAW
);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, sizeof(TrailVBOLayout), (GLvoid*)0); // stride : 4*sizeof(GL_FLOAT) + 2*sizeof(GL_DOUBLE)
glEnableVertexAttribArray(1);
glVertexAttribPointer(1, 2, GL_DOUBLE, GL_FALSE, sizeof(TrailVBOLayout), (GLvoid*)(4*sizeof(GL_FLOAT)) );
glBindVertexArray(0);
}
}
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