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https://github.com/MaSzyna-EU07/maszyna.git
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282 lines
9.2 KiB
C++
282 lines
9.2 KiB
C++
#include "stdafx.h"
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#include "sun.h"
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#include "Globals.h"
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#include "mtable.h"
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#include "utilities.h"
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#include "simulationtime.h"
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//////////////////////////////////////////////////////////////////////////////////////////
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// cSun -- class responsible for dynamic calculation of position and intensity of the Sun,
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cSun::cSun() {
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setLocation( 19.00f, 52.00f ); // default location roughly in centre of Poland
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m_observer.press = 1013.0; // surface pressure, millibars
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m_observer.temp = 15.0; // ambient dry-bulb temperature, degrees C
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}
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cSun::~cSun() { gluDeleteQuadric( sunsphere ); }
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void
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cSun::init() {
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m_observer.timezone = -1.0 * simulation::Time.zone_bias();
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sunsphere = gluNewQuadric();
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gluQuadricNormals( sunsphere, GLU_SMOOTH );
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}
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void
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cSun::update() {
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m_observer.temp = Global.AirTemperature;
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move();
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glm::vec3 position( 0.f, 0.f, -1.f );
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position = glm::rotateX( position, glm::radians( static_cast<float>( m_body.elevref ) ) );
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position = glm::rotateY( position, glm::radians( static_cast<float>( -m_body.hrang ) ) );
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m_position = glm::normalize( position );
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}
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void
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cSun::render() {
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::glColor4f( 255.f / 255.f, 242.f / 255.f, 231.f / 255.f, 1.f );
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// debug line to locate the sun easier
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auto const position { m_position * 2000.f };
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::glBegin( GL_LINES );
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::glVertex3fv( glm::value_ptr( position ) );
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::glVertex3f( position.x, 0.f, position.z );
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::glEnd();
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::glPushMatrix();
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::glTranslatef( position.x, position.y, position.z );
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// radius is a result of scaling true distance down to 2km -- it's scaled by equal ratio
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::gluSphere( sunsphere, m_body.distance * 9.359157, 12, 12 );
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::glPopMatrix();
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}
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/*
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glm::vec3
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cSun::getPosition() {
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return m_position * 1000.f * Global.fDistanceFactor;
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}
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*/
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glm::vec3
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cSun::getDirection() {
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return m_position;
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}
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float
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cSun::getAngle() {
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return (float)m_body.elevref;
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}
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// return current hour angle
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double
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cSun::getHourAngle() const {
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return m_body.hrang;
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}
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float cSun::getIntensity() {
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irradiance();
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return (float)( m_body.etr/ 1399.0 ); // arbitrary scaling factor taken from etrn value
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}
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void cSun::setLocation( float const Longitude, float const Latitude ) {
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// convert fraction from geographical base of 6o minutes
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m_observer.longitude = (int)Longitude + (Longitude - (int)(Longitude)) * 100.0 / 60.0;
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m_observer.latitude = (int)Latitude + (Latitude - (int)(Latitude)) * 100.0 / 60.0 ;
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}
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// sets current time, overriding one acquired from the system clock
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void cSun::setTime( int const Hour, int const Minute, int const Second ) {
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m_observer.hour = clamp( Hour, -1, 23 );
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m_observer.minute = clamp( Minute, -1, 59 );
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m_observer.second = clamp( Second, -1, 59 );
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}
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void cSun::setTemperature( float const Temperature ) {
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m_observer.temp = Temperature;
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}
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void cSun::setPressure( float const Pressure ) {
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m_observer.press = Pressure;
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}
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void cSun::move() {
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static double radtodeg = 57.295779513; // converts from radians to degrees
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static double degtorad = 0.0174532925; // converts from degrees to radians
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SYSTEMTIME localtime = simulation::Time.data(); // time for the calculation
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if( m_observer.hour >= 0 ) { localtime.wHour = m_observer.hour; }
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if( m_observer.minute >= 0 ) { localtime.wMinute = m_observer.minute; }
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if( m_observer.second >= 0 ) { localtime.wSecond = m_observer.second; }
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double localut =
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localtime.wHour
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+ localtime.wMinute / 60.0 // too low resolution, noticeable skips
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+ localtime.wSecond / 3600.0; // good enough in normal circumstances
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/*
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+ localtime.wMilliseconds / 3600000.0; // for really smooth movement
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*/
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double daynumber =
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367 * localtime.wYear
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- 7 * ( localtime.wYear + ( localtime.wMonth + 9 ) / 12 ) / 4
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+ 275 * localtime.wMonth / 9
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+ localtime.wDay
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- 730530
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+ ( localut / 24.0 );
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// Universal Coordinated (Greenwich standard) time
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m_observer.utime = localut - m_observer.timezone;
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// perihelion longitude
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m_body.phlong = 282.9404 + 4.70935e-5 * daynumber; // w
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// orbit eccentricity
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double const e = 0.016709 - 1.151e-9 * daynumber;
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// mean anomaly
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m_body.mnanom = clamp_circular( 356.0470 + 0.9856002585 * daynumber ); // M
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// obliquity of the ecliptic
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m_body.oblecl = 23.4393 - 3.563e-7 * daynumber;
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// mean longitude
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m_body.mnlong = clamp_circular( m_body.phlong + m_body.mnanom ); // L = w + M
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// eccentric anomaly
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double const E = m_body.mnanom + radtodeg * e * std::sin( degtorad * m_body.mnanom ) * ( 1.0 + e * std::cos( degtorad * m_body.mnanom ) );
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// ecliptic plane rectangular coordinates
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double const xv = std::cos( degtorad * E ) - e;
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double const yv = std::sin( degtorad * E ) * std::sqrt( 1.0 - e*e );
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// distance
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m_body.distance = std::sqrt( xv*xv + yv*yv ); // r
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// true anomaly
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m_body.tranom = radtodeg * std::atan2( yv, xv ); // v
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// ecliptic longitude
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m_body.eclong = clamp_circular( m_body.tranom + m_body.phlong ); // lon = v + w
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/*
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// ecliptic rectangular coordinates
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double const x = m_body.distance * std::cos( degtorad * m_body.eclong );
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double const y = m_body.distance * std::sin( degtorad * m_body.eclong );
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double const z = 0.0;
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// equatorial rectangular coordinates
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double const xequat = x;
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double const yequat = y * std::cos( degtorad * m_body.oblecl ) - 0.0 * std::sin( degtorad * m_body.oblecl );
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double const zequat = y * std::sin( degtorad * m_body.oblecl ) + 0.0 * std::cos( degtorad * m_body.oblecl );
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// declination
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m_body.declin = radtodeg * std::atan2( zequat, std::sqrt( xequat*xequat + yequat*yequat ) );
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// right ascension
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m_body.rascen = radtodeg * std::atan2( yequat, xequat );
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*/
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// declination
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m_body.declin = radtodeg * std::asin( std::sin( m_body.oblecl * degtorad ) * std::sin( m_body.eclong * degtorad ) );
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// right ascension
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double top = std::cos( degtorad * m_body.oblecl ) * std::sin( degtorad * m_body.eclong );
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double bottom = std::cos( degtorad * m_body.eclong );
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m_body.rascen = clamp_circular( radtodeg * std::atan2( top, bottom ) );
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// Greenwich mean sidereal time
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m_observer.gmst = 6.697375 + 0.0657098242 * daynumber + m_observer.utime;
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m_observer.gmst -= 24.0 * (int)( m_observer.gmst / 24.0 );
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if( m_observer.gmst < 0.0 ) m_observer.gmst += 24.0;
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// local mean sidereal time
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m_observer.lmst = m_observer.gmst * 15.0 + m_observer.longitude;
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m_observer.lmst -= 360.0 * (int)( m_observer.lmst / 360.0 );
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if( m_observer.lmst < 0.0 ) m_observer.lmst += 360.0;
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// hour angle
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m_body.hrang = m_observer.lmst - m_body.rascen;
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if( m_body.hrang < -180.0 ) m_body.hrang += 360.0; // (force it between -180 and 180 degrees)
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else if( m_body.hrang > 180.0 ) m_body.hrang -= 360.0;
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double cz; // cosine of the solar zenith angle
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double tdatcd = std::cos( degtorad * m_body.declin );
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double tdatch = std::cos( degtorad * m_body.hrang );
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double tdatcl = std::cos( degtorad * m_observer.latitude );
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double tdatsd = std::sin( degtorad * m_body.declin );
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double tdatsl = std::sin( degtorad * m_observer.latitude );
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cz = tdatsd * tdatsl + tdatcd * tdatcl * tdatch;
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// (watch out for the roundoff errors)
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if( fabs( cz ) > 1.0 ) { cz >= 0.0 ? cz = 1.0 : cz = -1.0; }
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m_body.zenetr = std::acos( cz ) * radtodeg;
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m_body.elevetr = 90.0 - m_body.zenetr;
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refract();
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}
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void cSun::refract() {
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static double raddeg = 0.0174532925; // converts from degrees to radians
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double prestemp; // temporary pressure/temperature correction
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double refcor; // temporary refraction correction
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double tanelev; // tangent of the solar elevation angle
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// if the sun is near zenith, the algorithm bombs; refraction near 0.
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if( m_body.elevetr > 85.0 )
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refcor = 0.0;
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else {
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tanelev = tan( raddeg * m_body.elevetr );
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if( m_body.elevetr >= 5.0 )
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refcor = 58.1 / tanelev
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- 0.07 / pow( tanelev, 3 )
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+ 0.000086 / pow( tanelev, 5 );
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else if( m_body.elevetr >= -0.575 )
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refcor = 1735.0
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+ m_body.elevetr * ( -518.2 + m_body.elevetr *
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( 103.4 + m_body.elevetr * ( -12.79 + m_body.elevetr * 0.711 ) ) );
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else
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refcor = -20.774 / tanelev;
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prestemp = ( m_observer.press * 283.0 ) / ( 1013.0 * ( 273.0 + m_observer.temp ) );
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refcor *= prestemp / 3600.0;
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}
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// refracted solar elevation angle
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m_body.elevref = m_body.elevetr + refcor;
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// refracted solar zenith angle
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m_body.zenref = 90.0 - m_body.elevref;
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}
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void cSun::irradiance() {
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m_body.dayang = ( simulation::Time.year_day() - 1 ) * 360.0 / 365.0;
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double sd = std::sin( glm::radians( m_body.dayang ) ); // sine of the day angle
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double cd = std::cos( glm::radians( m_body.dayang ) ); // cosine of the day angle or delination
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m_body.erv = 1.000110 + 0.034221*cd + 0.001280*sd;
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double d2 = 2.0 * m_body.dayang;
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double c2 = std::cos( glm::radians( d2 ) );
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double s2 = std::sin( glm::radians( d2 ) );
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m_body.erv += 0.000719*c2 + 0.000077*s2;
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double solcon = 1367.0; // Solar constant, 1367 W/sq m
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m_body.coszen = std::cos( glm::radians( m_body.zenref ) );
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if( m_body.coszen > 0.0 ) {
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m_body.etrn = solcon * m_body.erv;
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m_body.etr = m_body.etrn * m_body.coszen;
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}
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else {
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m_body.etrn = 0.0;
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m_body.etr = 0.0;
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}
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}
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