vector3d SpaceStation::GetTargetIndicatorPosition(const Frame *relTo) const
{
// return the next waypoint if permission has been granted for player,
// and the docking point's position once the docking anim starts
for (int i=0; i<MAX_DOCKING_PORTS; i++) {
if (i >= m_type->numDockingPorts) break;
if ((m_shipDocking[i].ship == Pi::player) && (m_shipDocking[i].stage > 0)) {
SpaceStationType::positionOrient_t dport;
if (!m_type->GetShipApproachWaypoints(i, m_shipDocking[i].stage+1, dport))
PiVerify(m_type->GetDockAnimPositionOrient(i, m_type->numDockingStages,
1.0f, vector3d(0.0), dport, m_shipDocking[i].ship));
vector3d v = GetInterpPositionRelTo(relTo);
return v + GetInterpOrientRelTo(relTo) * dport.pos;
}
}
return GetInterpPositionRelTo(relTo);
}
vector3d Body::GetTargetIndicatorPosition(const Frame *relTo) const
{
return GetInterpPositionRelTo(relTo);
}
// Calculates the ambiently and directly lit portions of the lighting model taking into account the atmosphere and sun positions at a given location
// 1. Calculates the amount of direct illumination available taking into account
// * multiple suns
// * sun positions relative to up direction i.e. light is dimmed as suns set
// * Thickness of the atmosphere overhead i.e. as atmospheres get thicker light starts dimming earlier as sun sets, without atmosphere the light switches off at point of sunset
// 2. Calculates the split between ambient and directly lit portions taking into account
// * Atmosphere density (optical thickness) of the sky dome overhead
// as optical thickness increases the fraction of ambient light increases
// this takes altitude into account automatically
// * As suns set the split is biased towards ambient
void ModelBody::CalcLighting(double &ambient, double &direct, const Camera *camera)
{
const double minAmbient = 0.05;
ambient = minAmbient;
direct = 1.0;
Body *astro = GetFrame()->GetBody();
if ( ! (astro && astro->IsType(Object::PLANET)) )
return;
Planet *planet = static_cast<Planet*>(astro);
// position relative to the rotating frame of the planet
vector3d upDir = GetInterpPositionRelTo(planet->GetFrame());
const double planetRadius = planet->GetSystemBody()->GetRadius();
const double dist = std::max(planetRadius, upDir.Length());
upDir = upDir.Normalized();
double pressure, density;
planet->GetAtmosphericState(dist, &pressure, &density);
double surfaceDensity;
Color cl;
planet->GetSystemBody()->GetAtmosphereFlavor(&cl, &surfaceDensity);
// approximate optical thickness fraction as fraction of density remaining relative to earths
double opticalThicknessFraction = density/EARTH_ATMOSPHERE_SURFACE_DENSITY;
// tweak optical thickness curve - lower exponent ==> higher altitude before ambient level drops
// Commenting this out, since it leads to a sharp transition at
// atmosphereRadius, where density is suddenly 0
//opticalThicknessFraction = pow(std::max(0.00001,opticalThicknessFraction),0.15); //max needed to avoid 0^power
if (opticalThicknessFraction < 0.0001)
return;
//step through all the lights and calculate contributions taking into account sun position
double light = 0.0;
double light_clamped = 0.0;
const std::vector<Camera::LightSource> &lightSources = camera->GetLightSources();
for(std::vector<Camera::LightSource>::const_iterator l = lightSources.begin();
l != lightSources.end(); ++l) {
double sunAngle;
// calculate the extent the sun is towards zenith
if (l->GetBody()){
// relative to the rotating frame of the planet
const vector3d lightDir = (l->GetBody()->GetInterpPositionRelTo(planet->GetFrame()).Normalized());
sunAngle = lightDir.Dot(upDir);
} else {
// light is the default light for systems without lights
sunAngle = 1.0;
}
const double critAngle = -sqrt(dist*dist-planetRadius*planetRadius)/dist;
//0 to 1 as sunangle goes from critAngle to 1.0
double sunAngle2 = (Clamp(sunAngle, critAngle, 1.0)-critAngle)/(1.0-critAngle);
// angle at which light begins to fade on Earth
const double surfaceStartAngle = 0.3;
// angle at which sun set completes, which should be after sun has dipped below the horizon on Earth
const double surfaceEndAngle = -0.18;
const double start = std::min((surfaceStartAngle*opticalThicknessFraction),1.0);
const double end = std::max((surfaceEndAngle*opticalThicknessFraction),-0.2);
sunAngle = (Clamp(sunAngle-critAngle, end, start)-end)/(start-end);
light += sunAngle;
light_clamped += sunAngle2;
}
light_clamped /= lightSources.size();
light /= lightSources.size();
// brightness depends on optical depth and intensity of light from all the stars
direct = 1.0 - Clamp((1.0 - light),0.0,1.0) * Clamp(opticalThicknessFraction,0.0,1.0);
// ambient light fraction
// alter ratio between directly and ambiently lit portions towards ambiently lit as sun sets
const double fraction = ( 0.2 + 0.8 * (1.0-light_clamped) ) * Clamp(opticalThicknessFraction,0.0,1.0);
// fraction of light left over to be lit directly
direct = (1.0-fraction)*direct;
// scale ambient by amount of light
ambient = fraction*(Clamp((light),0.0,1.0))*0.25;
ambient = std::max(minAmbient, ambient);
}
vector3d Body::GetInterpPositionRelTo(const Body *relTo) const
{
return GetInterpPositionRelTo(relTo->m_frame) - relTo->GetInterpPosition();
}
