double AscentAP::GetTargetInclination ()
{
double a=0.0, B=0.0;
if (vessel->status == 0) {
if (!launch_lat && !launch_lng) {
double r;
vessel->GetEquPos(launch_lng, launch_lat, r);
}
a = PI05-launch_lat;
// correct launch azimuth for surface rotation
const OBJHANDLE hRef = vessel->GetGravityRef();
double R = oapiGetSize(hRef); // planet mean radius
double r = R + tgt_alt; // target orbit radius
double M = oapiGetMass (hRef); // reference body mass
double v0 = sqrt(GGRAV*M/r); // target orbit speed
double vg = PI2*R/oapiGetPlanetPeriod(hRef)*cos(launch_lat);
// surface speed at launch position
double vx0 = v0*sin(launch_azimuth); // longitudinal velocity component
double vx1 = vx0 + vg; // corrected for planet rotation
double vy = v0*cos(launch_azimuth); // latitudinal velocity component
B = atan2(vx1,vy); // effective launch azimuth
}
return PI05 - asin(sin(a)*sin(B));
}
void AttitudeReference::PostStep (double simt, double simdt, double mjd)
{
valid_axes = false;
valid_euler = false;
valid_tgteuler = false;
if (mode >= 4 && tgtmode == 3) {
NAVHANDLE hNav = v->GetNavSource (navid);
if (hNav) {
VECTOR3 tvel,svel;
v->GetGlobalVel (svel);
NAVDATA data;
OBJHANDLE hObj = NULL;
oapiGetNavData (hNav, &data);
switch (data.type) {
case TRANSMITTER_IDS:
hObj = data.ids.hVessel;
break;
case TRANSMITTER_XPDR:
hObj = data.xpdr.hVessel;
break;
case TRANSMITTER_VTOL:
hObj = data.vtol.hBase;
break;
case TRANSMITTER_VOR: {
hObj = data.vor.hPlanet;
MATRIX3 Rp;
oapiGetRotationMatrix (hObj, &Rp);
oapiGetGlobalVel (hObj, &tvel);
tvel += mul (Rp, _V(-sin(data.vor.lng),0,cos(data.vor.lng)) * PI2/oapiGetPlanetPeriod(hObj)*oapiGetSize(hObj)*cos(data.vor.lat));
tgt_rvel = svel-tvel;
sprintf (oapiDebugString(), "rvel: x=%f, y=%f, z=%f", tgt_rvel.x, tgt_rvel.y, tgt_rvel.z);
} return; // done
}
if (hObj) {
oapiGetGlobalVel (hObj, &tvel);
tgt_rvel = svel-tvel;
} else {
// TODO
}
}
}
}
// ==============================================================================================================================================
//
void Orbit::GEO(OBJHANDLE ref)
{
if (!ref) { GeoRef=NULL; return; }
double obli = oapiGetPlanetObliquity(ref);
double peri = oapiGetPlanetPeriod(ref);
double trans = oapiGetPlanetTheta(ref);
VECTOR3 rota, refd;
PlanetAxis(obli,trans,&rota,&refd);
VECTOR3 velo = crossp(rota,refd);
double myy = oapiGetMass(ref)*GC;
double rad = pow(fabs(peri)*sqrt(myy)/PI2, 2.0 / 3.0);
double vel = sqrt(myy/rad);
refd=set_length(refd,rad);
velo=set_length(velo,vel);
if (peri<0) velo=_V(0,0,0)-velo;
Elements(refd,velo,myy);
GeoRef=ref;
}
// ==============================================================================================================================================
//
void SyncMFD::Update(HDC hDC)
{
int pos;
int ld=MFD->LineHeight;
int fbp=MFD->FirstButton;
char *Mnu = {"BaseSync v3.2\0"};
int width=MFD->width;
int height=MFD->height;
double w=(double) width;
double h=(double) height;
int i;
VECTOR3 Rot,Off,opos;
double obli,trans,per,offset,diff,p,op,t,time,lon,lat;
double trl,heading;
char name[32];
static const int MAXSOLN = 160;
double times[MAXSOLN],diffs[MAXSOLN],heads[MAXSOLN];
int sol_found = 0;
double max_diff=1000;
bool draw_text=false;
Orbit LEO,ShipOrbit,Ecliptic;
SetTextColor(hDC,white);
SetTextAlign(hDC,TA_LEFT);
TextOut(hDC,5,1,Mnu, (int)strlen(Mnu));
if (mode.enc==0) Text(hDC,5,1+ld,"Latitude");
if (mode.enc==1) Text(hDC,5,1+ld,"Closest passage");
if (mode.enc==2) Text(hDC,5,1+ld,"Apoapsis");
if (mode.enc==3) Text(hDC,5,1+ld,"Periapsis");
if (sync_num<1) sync_num=1;
if (sync_num>99) sync_num=99;
OBJHANDLE ref = oapiGetObjectByName(trgt->ref);
if (ref==NULL) {
usingGS2 = false;
trgt = &bstrgt;
ref=ship->GetSurfaceRef();
}
if (ref==NULL) return;
ShipOrbit.Elements(ship->GetHandle(), ref);
Ecliptic.Ecliptic();
oapiGetObjectName(ref, trgt->ref, 31);
// Rotation elements
obli = oapiGetPlanetObliquity(ref);
trans = oapiGetPlanetTheta(ref);
per = oapiGetPlanetPeriod(ref);
offset = oapiGetPlanetCurrentRotation(ref);
// LEO
LEO.LEO(ref);
if (!usingGS2) {
OBJHANDLE tgt = oapiGetBaseByName(ref, trgt->name);
if (tgt) {
oapiGetObjectName(tgt,trgt->name,32);
oapiGetBaseEquPos(tgt,&trgt->lon, &trgt->lat);
}
else strcpy(trgt->name,"Surface");
}
double trle=ShipOrbit.TrlOfNode(&LEO);
double EqI=angle(ShipOrbit.norv, LEO.norv);
double ang=asin(sin(trgt->lat) / sin(EqI));
double apos=limit(trle+ang);
double bpos=limit(trle+PI-ang);
double atime=ShipOrbit.TimeTo(apos);
double btime=ShipOrbit.TimeTo(bpos);
double dist=ShipOrbit.PeriapsisDistance();
double apodist = dist=ShipOrbit.AopapsisDistance();
if (dist<oapiGetSize(ref)) dist=oapiGetSize(ref);
double zoom=w/(2.55 * (apodist + apodist + dist) / 3.0);
double r=oapiGetSize(ref)*zoom;
double x=w/2,y=h/2;
double intpos=0;
if (display_texts&2) {
SelectObject(hDC,solid_pen_dgrey);
DrawEllipse(hDC,x-r,y-r,x+r,y+r,w,h);
if (mode.enc==0) { // Latitude
if ((sync_sel&1)==0) SelectObject(hDC,solid_pen_y), intpos=apos;
else SelectObject(hDC,solid_pen_dgrey);
r=ShipOrbit.Radius(apos)*zoom;
DrawLine(hDC,x,y,x+r*cos(apos),x-r*sin(apos),w,h,false);
if ((sync_sel&1)==1) SelectObject(hDC,solid_pen_y), intpos=bpos;
else SelectObject(hDC,solid_pen_dgrey);
r=ShipOrbit.Radius(bpos)*zoom;
DrawLine(hDC,x,y,x+r*cos(bpos),x-r*sin(bpos),w,h,false);
}
if (mode.enc==1) { // Closest Passage
r=ShipOrbit.Radius(sync_trl)*zoom;
intpos=sync_trl;
SelectObject(hDC,solid_pen_y);
DrawLine(hDC,x,y,x+r*cos(sync_trl),x-r*sin(sync_trl),w,h,false);
}
if (mode.enc==2 || mode.enc==3) { // Aopapsis Periapsis
SelectObject(hDC,solid_pen_y);
r=ShipOrbit.Radius(sync_trl)*zoom;
DrawLine(hDC,x,y,x+r*cos(sync_trl),x-r*sin(sync_trl),w,h,false);
SelectObject(hDC,solid_pen_grey);
r=ShipOrbit.Radius(sync_line)*zoom;
DrawLine(hDC,x,y,x+r*cos(sync_line),x-r*sin(sync_line),w,h,false);
}
ShipOrbit.SetProjection(&ShipOrbit);
ShipOrbit.GDIDraw(hDC,green,w,h,zoom,true,true);
if (mode.deo) {
r=ShipOrbit.Radius(deo.trlBurn)*zoom;
SelectObject(hDC,solid_pen_white);
DrawLine(hDC,x,y,x+r*cos(deo.trlBurn),x-r*sin(deo.trlBurn),w,h,false);
}
}
if (EqI>=trgt->lat || mode.enc!=0) {
// Usual case... target in range
draw_text=true;
SetTextColor(hDC,green);
pos=(fbp+(ld*8));
if (display_texts&1 && !mode.deo) {
if (mode.enc==0) {
Text(hDC,5,pos," #: Time:");
Text(hDC,width/2,pos,"Lon Diff:"), pos+=ld;
} else {
Text(hDC,5,pos," #: Time:");
Text(hDC,5+width/3,pos," Dist:");
Text(hDC,5+width*2/3,pos," Heading:"), pos+=ld;
}
}
if (atime<btime && atime>0) sync_sel=0;
else if (btime>0) sync_sel=1;
else sync_sel=0;
for (i=0;i<MAXSOLN;i++) {
times[i]=0;
diffs[i]=0;
}
sync_min = -1;
if (ShipOrbit.ecc<1 && mode.enc==0) {
for (i=0;i<MAXSOLN;i++) {
if (i&1) time=MAX(atime, btime);
else time=MIN(atime, btime);
if (time==atime) op=apos;
else op=bpos;
p=(double)i;
if (i>1) time+=ShipOrbit.Period()*floor(p/2);
t = time/86400;
PlanetAxis(obli,trans,offset,per,t,&Rot,&Off);
opos=ShipOrbit.Position(op);
LonLat(opos,Rot,Off,&lon,&lat);
diff=lon-trgt->lon;
if (fabs(diff)<max_diff) {
max_diff=fabs(diff), sync_time=time, sync_trl=op;
sync_min=i;
}
times[i]=time;
diffs[i]=diff;
if (time > 0.0 && diff >0.0) {
sol_found++;
if (sol_found==sync_num) break;
}
}
}
max_diff=1e10;
if (ShipOrbit.ecc<1 && mode.enc==1) {
double posit=ShipOrbit.trl;
for (i=0;i<MAXSOLN;i++) {
InterpolateClosestPassage(ref,&ShipOrbit,trgt->lon,trgt->lat,posit,&diff,&time,&heading,&trl);
posit=trl+PI05;
if (diff<max_diff && diff>0) {
max_diff=diff, sync_time=time, sync_trl=limit(trl);
sync_min=i;
}
heads[i]=heading;
times[i]=time;
diffs[i]=diff;
if (time > 0.0 && diff >0.0) {
sol_found++;
if (sol_found==sync_num) break;
}
}
}
if (ShipOrbit.ecc<1 && (mode.enc==2 || mode.enc==3)) {
for (i=0;i<MAXSOLN;i++) {
if (mode.enc==2) sync_line=limit(ShipOrbit.lpe+PI);
else sync_line=limit(ShipOrbit.lpe);
time=ShipOrbit.TimeTo(sync_line) + ShipOrbit.Period() * (double)i;
t = time / 86400.0;
PlanetAxis(obli,trans,offset,per,t,&Rot,&Off);
VECTOR3 gpv=VectorByLonLat(Rot,Off,trgt->lon,trgt->lat);
VECTOR3 pos=ShipOrbit.Position(sync_line);
diff = angle(gpv,pos);
heading = nangle(pos-gpv,Rot,gpv);
ShipOrbit.Longitude(gpv,NULL,NULL,&trl);
if (diff<max_diff && diff>0) {
max_diff=diff, sync_time=time, sync_trl=limit(trl);
sync_min=i;
}
if (time==0) time=0.1;
heads[i]=heading;
times[i]=time;
diffs[i]=diff;
if (time > 0.0 && diff >0.0) {
sol_found++;
if (sol_found==sync_num) break;
}
}
}
// Hyperbolic Orbit
if (ShipOrbit.ecc>=1 && (atime>0 || btime>0)) {
mode.enc=0;
for (i=0;i<2;i++) {
if (atime>0 && btime>0) {
if (i&1) time=MAX(atime, btime);
else time=MIN(atime, btime);
}
else time=(atime>0 ? atime : btime);
op = (time==atime? apos : bpos);
p=(double)i;
if (i>1) time+=ShipOrbit.Period()*floor(p/2);
t = time/86400;
PlanetAxis(obli,trans,offset,per,t,&Rot,&Off);
opos=ShipOrbit.Position(op);
LonLat(opos,Rot,Off,&lon,&lat);
diff=lon-trgt->lon;
if (fabs(diff)<max_diff) {
max_diff=fabs(diff), sync_time=time, sync_trl=op;
sync_min=i;
}
times[i]=time;
diffs[i]=diff;
if (atime<0 || btime<0) break;
}
}
if (sync_min > -1) {
sol.num = sync_min+1;
sol.tSol = times[sync_min];
sol.dist = diffs[sync_min];
sol.hdg = heads[sync_min];
sol.dataValid = true;
} else {
sol.dataValid = false;
}
double rad=oapiGetSize(ref);
int no=0;
int disp_i = 1;
if (display_texts&1 && !mode.deo) {
for (i=0;i<MAXSOLN;i++) {
if (i==sync_min) SetTextColor(hDC,lyellow);
else SetTextColor(hDC,lgreen);
if (times[i]>0.0 && diffs[i]>=0.0) {
if (disp_i >= sync_dispmin && disp_i <= sync_dispmin+7) {
if (mode.enc==0) {
sprintf(name,"%2d: ",disp_i);
Text(hDC,5,pos,name,times[i]);
TextA(hDC,width/2,pos,"",diffs[i]*DEG), pos+=ld;
} else { // enc_mode 1,2,3
no++;
sprintf(name,"%2d: ",disp_i);
Text(hDC,5,pos,name,times[i]);
Text(hDC,5+width/3,pos," ",diffs[i]*rad);
TextA(hDC,5+width*2/3,pos," ",heads[i]*DEG), pos+=ld;
}
}
disp_i++;
if (disp_i > sync_num) break;
}
}
}
sync_sel+=sync_min;
} else {
// We are in Latitude mode, and the target is outside of our inclination - i.e. no solution
sol.dataValid = false;
SetTextAlign(hDC,TA_CENTER);
SetTextColor(hDC,yellow);
pos=(fbp+(ld*8));
Text(hDC,width/2,pos,"Target Out of Range"); pos+=ld;
}
if (mode.dir) {
// Calculate burn for plane change correction in DIRECT mode
if (EqI<trgt->lat && mode.enc==0) {
double trl;
PlanetAxis(obli,trans,offset,per,0,&Rot,&Off);
VECTOR3 gpv = VectorByLonLat(Rot,Off,trgt->lon,trgt->lat);
ShipOrbit.Longitude(gpv,NULL,NULL,&trl);
sync_time=ShipOrbit.TimeTo(trl);
sync_trl=trl;
}
time_to_int=sync_time;
double trl=sync_trl;
PlanetAxis(obli,trans,offset,per,time_to_int/86400.0,&Rot,&Off);
VECTOR3 pos = ShipOrbit.Position(trl);
VECTOR3 gpv = VectorByLonLat(Rot,Off,trgt->lon,trgt->lat);
VECTOR3 lan = crossp(gpv, pos);
VECTOR3 nor = ShipOrbit.norv;
ShipOrbit.Longitude(lan,NULL,NULL,&sol.trlBurn);
sol.rIn = fabs(asin(dotp(gpv,nor)));
double a = ShipOrbit.TimeToPoint(sol.trlBurn);
double b = ShipOrbit.TimeToPoint(limit(sol.trlBurn+PI));
if (fabs(a)<fabs(b)) sol.tToBurn =a, sol.nmlBurn=true;
else sol.tToBurn =b, sol.nmlBurn=false;
sol.dV = sol.rIn*ShipOrbit.ang/ShipOrbit.Radius(sol.trlBurn);
sol.tBurn =BurnTimeBydV(sol.dV,ship);
} else {
// Calculate burn for plane change correction in EQUATORIAL mode
sol.trlBurn=ShipOrbit.TrlOfNode(&LEO);
sol.rIn=MAX(trgt->lat-EqI,0);
double a=ShipOrbit.TimeToPoint(sol.trlBurn);
double b=ShipOrbit.TimeToPoint(limit(sol.trlBurn+PI));
if (fabs(a)<fabs(b)) sol.tToBurn =a, sol.nmlBurn=true;
else sol.tToBurn =b, sol.nmlBurn=false;
sol.dV = sol.rIn*ShipOrbit.ang/ShipOrbit.Radius(sol.trlBurn);
sol.tBurn =BurnTimeBydV(sol.dV,ship);
}
if (display_texts&2) {
ShipOrbit.DrawPlaneIntersection(hDC,sol.trlBurn,w/2,h/2,zoom,grey);
}
SetTextAlign(hDC,TA_LEFT);
pos=1;
SetTextColor(hDC,grey);
if (usingGS2) {
Text(hDC,width*1/2,pos,"Linked ","to GS"); pos+=ld;
// Check if GS2 changed target
if (bstrgt.lat != gs2trgt->lat || bstrgt.lon != gs2trgt->lon) {
strcpy(bstrgt.ref, gs2trgt->ref);
strcpy(bstrgt.name, gs2trgt->name);
bstrgt.lat = gs2trgt->lat;
bstrgt.lon = gs2trgt->lon;
bstrgt.alt = gs2trgt->alt;
bstrgt.ang = gs2trgt->ang;
bstrgt.ant = gs2trgt->ant;
}
} else {
Text(hDC,width*1/2,pos,"Ref ",trgt->ref); pos+=ld;
}
Text(hDC,width*1/2,pos,"Tgt ",trgt->name); pos+=ld;
if (display_texts&1) {
if (!mode.deo) {
// Display the burn solution for plane change
deo.dataValid = false;
pos=fbp;
SetTextColor(hDC,lgreen);
if (trgt->lat<0) TextA(hDC,5,pos,"Lat ",fabs(DEG*trgt->lat),"S"), pos+=ld;
else TextA(hDC,5,pos,"Lat ",DEG*trgt->lat,"N"), pos+=ld;
if (trgt->lon<0) TextA(hDC,5,pos,"Lon ",fabs(DEG*trgt->lon),"W"), pos+=ld;
else TextA(hDC,5,pos,"Lon ",DEG*trgt->lon,"E"), pos+=ld;
TextA(hDC,5,pos,"EqI ",EqI*DEG), pos+=ld;
PlanetAxis(ref,0,&Rot,&Off);
VECTOR3 base_pos = VectorByLonLat(Rot,Off,trgt->lon,trgt->lat);
VECTOR3 ship_pos; ship->GetRelativePos(ref,ship_pos);
VECTOR3 ship_vel; ship->GetRelativeVel(ref,ship_vel);
VECTOR3 gsp=GroundSpeedVector(ref,ship);
VECTOR3 zero=crossp(ship_pos,ship_vel);
double head = nangle(gsp,zero,ship_pos);
double baseHeight = oapiGetSize(ref);
#if ORBITER_VERSION == 2016
ELEVHANDLE eh = oapiElevationManager(ref);
if (eh) {
baseHeight += oapiSurfaceElevation(ref, trgt->lon, trgt->lat);
}
#endif
TextA(hDC,5,pos,"Hed ",head*DEG), pos+=ld;
Text(hDC,5,pos, "GSp ",length(gsp)), pos+=ld;
Text(hDC,5,pos, "Dst ",angle(ship_pos,base_pos)*baseHeight), pos+=ld;
if (sol.dataValid) {
double altitude = length(ShipOrbit.Position(intpos));
altitude -= baseHeight;
Text(hDC,5,pos, "Alt ",altitude);
}
pos+=ld;
pos=fbp;
int xx=width/2;
SetTextColor(hDC,green);
if (mode.dir) Text(hDC,xx,pos,"Direct:"), pos+=ld;
else Text(hDC,xx,pos,"Equator:"), pos+=ld;
SetTextColor(hDC,lgreen);
TextA(hDC,xx,pos,"RIn ",sol.rIn*DEG), pos+=ld;
TextA(hDC,xx,pos,"LAN ",sol.trlBurn*DEG), pos+=ld;
Text(hDC,xx,pos," Tn ",sol.tToBurn), pos+=ld;
if (abs(sol.tBurn) > 0.1) {
if (sol.nmlBurn) Text(hDC,xx,pos,"PlC ",sol.tBurn,"s (+)"), pos+=ld;
else Text(hDC,xx,pos,"PlC ",sol.tBurn,"s (-)"), pos+=ld;
Text(hDC,xx,pos," dV ",sol.dV,"m/s"), pos+=ld;
} else {
Text(hDC,xx,pos,"PlC 0.000s"), pos+=ld;
Text(hDC,xx,pos," dV 0.000m/s"), pos+=ld;
}
if (sol.dataValid) {
burn.dV = sol.dV;
burn.orientation = sol.nmlBurn ? 1 : -1;
burn.tToInstBurn = sol.tToBurn;
burn.dataValid = true;
} else {
burn.dataValid = false;
}
} else {
// Display the deorbit parameters and burn solution
pos=fbp;
SetTextColor(hDC,white);
Text(hDC,5,pos,"De-Orbit Program"), pos+=2*ld;
SetTextColor(hDC,lgreen);
if (usingGS2) {
Text(hDC,5,pos, "Ang, Ant, Alt from GS"), pos+=ld;
TextA(hDC,5,pos,"GS Ang ",trgt->ang*DEG), pos+=ld;
TextA(hDC,5,pos,"GS Ant ",trgt->ant*DEG), pos+=ld;
Text(hDC,5,pos, "GS Alt ",trgt->alt,"km"), pos+=2*ld;
} else {
TextA(hDC,5,pos,"Ang ",bstrgt.ang*DEG), pos+=ld;
TextA(hDC,5,pos,"Ant ",bstrgt.ant*DEG), pos+=ld;
Text(hDC,5,pos, "Alt ",bstrgt.alt,"km"), pos+=2*ld;
}
double pre;
ComputeDeOrbit(ShipOrbit.myy,ShipOrbit.rad,trgt->alt*1000+oapiGetSize(ref),trgt->ang,&pre,&deo.dV);
deo.dV=ShipOrbit.vel-deo.dV;
deo.trlBurn = limit(sync_trl - trgt->ant - pre);
deo.tInstBurn = ShipOrbit.TimeToPoint(deo.trlBurn);
deo.tBurn = BurnTimeBydV(deo.dV,ship);
deo.tToBurn = deo.tInstBurn - 0.5 * deo.tBurn;
Text(hDC,5,pos, "TBn ",deo.tToBurn,"s"), pos+=ld;
TextA(hDC,5,pos,"TrL ",deo.trlBurn*DEG), pos+=ld;
Text(hDC,5,pos, " dV ",deo.dV,"m/s"), pos+=ld;
Text(hDC,5,pos, " BT ",deo.tBurn,"s"), pos+=2*ld;
if (ShipOrbit.ecc>0.015) {
SetTextColor(hDC,lgreen);
Text(hDC,5,pos,"De-orbit burn data only accurate"); pos+=ld;
Text(hDC,5,pos,"if your Ecc is 0.015 or less."); pos+=ld;
Text(hDC,5,pos,"(If burn complete, please ignore.)"); pos+=ld;pos+=ld;
}
if (!mode.dir) {
SetTextColor(hDC,lgreen);
Text(hDC,5,pos,"Use \"Direct\" mode to re-synchronize"); pos+=ld;
Text(hDC,5,pos,"the approach after the de-orbit");
}
deo.dataValid = true;
burn.dV = -deo.dV;
burn.orientation = 0;
burn.tToInstBurn = deo.tToBurn;
burn.dataValid = true;
}
}
if (!MMPut_done) {
mma.PutMMStruct("BaseSyncTarget", &bstrgt);
mma.PutMMStruct("BaseSyncMode", &mode);
mma.PutMMStruct("BaseSyncSolution", &sol);
mma.PutMMStruct("BaseSyncDeorbit", &deo);
mma.PutMMStruct("BaseSyncBurn", &burn); // To be removed after BTC synchronization
if (burn.dataValid)
{
mma.Put("dv", burn.dV);
mma.Put("InstantaneousBurnTime", burn.tToInstBurn);
mma.Put("Orientation", burn.orientation);
}
else
{
mma.Delete("dv");
mma.Delete("InstantaneousBurnTime");
mma.Delete("Orientation");
}
MMPut_done = true;
}
}
// ==============================================================================================================================================
//
bool SyncMFD::InterpolateClosestPassage(OBJHANDLE ref, Orbit *src, double lon,double lat,double orbit,double *diff,double *tim,double *head,double *tr)
{
VECTOR3 Rot,Off;
Orbit LEO;
int i;
double obli = 0.0;
double trans = 0.0;
double per = 0.0;
double offset = 0.0;
double size = 0.0;
double time = 0.0;
// Rotation elements
obli = oapiGetPlanetObliquity(ref);
trans = oapiGetPlanetTheta(ref);
per = oapiGetPlanetPeriod(ref);
offset = oapiGetPlanetCurrentRotation(ref);
size = oapiGetSize(ref);
LEO.LEO(ref);
double step = PI2/16.01;
double start = orbit;
double end = orbit+PI2+(step/2.0);
double trl, dst2;
double dot,old_dot=0;
VECTOR3 pos = _V(0,0,0);
VECTOR3 vel = _V(0,0,0);
VECTOR3 gpv = _V(0,0,0);
VECTOR3 spd = _V(0,0,0);
VECTOR3 relv = _V(0,0,0);
VECTOR3 relp = _V(0,0,0);
bool no_intercept=true;
bool first=true;
for (trl=start;trl<end;trl+=step) {
// Caluclate time to a location
time=Trl2Time(trl,src)/86400.0;
// Caluclate Planets Rotation offset at that time
PlanetAxis(obli,trans,offset,per,time,&Rot,&Off);
// Calculate Ship's position vector and distance^2
pos = src->Position(trl);
dst2 = dotp(pos,pos);
// Reset the distance to correspond a surface position.
pos = set_length(pos,size);
// Compute ship's surface velocity vector direction
vel = crossp(src->norv,pos);
// Compute ship's surface velocity vector magnitude
vel = set_length(vel,src->ang*size/dst2);
// Compute base's position vector
gpv = VectorByLonLat(Rot,Off,lon,lat)*size;
// Compute speed of the base
spd = GroundSpeedVector(ref,time,lon,lat);
// Copmute relative position to the base
relv = (vel-spd);
relp = (pos-gpv);
dot = dotp(relv,relp);
if (old_dot<0 && dot>0 && !first) {
if (angle(pos,gpv)<PI05) {
start=trl-step;
no_intercept=false;
break;
}
}
first=false;
old_dot=dot;
}
// Return N/A if no passage points found
if (no_intercept) {
if (head) *head = 0;
if (diff) *diff = 0;
if (tim) *tim = 0;
if (tr) *tr = start+PI2-PI05;
return false;
}
trl=start;
old_dot=-1; // We are approaching the base
double trll=0;
no_intercept=true;
for (i=0;i<24;i++) {
step/=2.0;
// Caluclate time to a location
time=Trl2Time(trl,src)/86400.0;
// Caluclate Planets Rotation offset at that time
PlanetAxis(obli,trans,offset,per,time,&Rot,&Off);
// Calculate Ship's position vector and distance^2
pos = src->Position(trl);
dst2 = dotp(pos,pos);
// Reset the distance to correspond a surface position.
pos = set_length(pos,size);
// Compute ship's surface velocity vector direction
vel = crossp(src->norv,pos);
// Compute ship's surface velocity vector magnitude
vel = set_length(vel,src->ang*size/dst2);
// Compute base's position vector
gpv = VectorByLonLat(Rot,Off,lon,lat)*size;
// Compute speed of the base
spd = GroundSpeedVector(ref,time,lon,lat);
// Copmute relative position to the base
relv = (vel-spd);
relp = (pos-gpv);
dot = dotp(relv,relp);
trll=trl;
if (dot==0) {
no_intercept=false;
break; // closest position archived, break
}
if (dot>0) { // base is behind of us, step back
trl=trl-step;
no_intercept=false; // Verify, We have a base passage.
}
else trl=trl+step; // base is front of us, cuntinue stepping
}
double dif=angle(pos, gpv);
VECTOR3 zero=crossp(pos,spd);
if (head) *head = nangle(relp,zero,pos);
if (diff) *diff = dif;
if (tim) *tim = time*86400.0;
if (tr) *tr = trll;
return true;
}
