/* * Function: SpawnShipLanded * * Create a ship and place it landed on the given <Body>. * * > ship = Space.SpawnShipLanded(type, body, lat, long) * * Parameters: * * type - the name of the ship * * body - the <Body> near which the ship should be spawned * * lat - latitude in radians (like in custom body defintions) * * long - longitude in radians (like in custom body definitions) * * Return: * * ship - a <Ship> object for the new ship * * Example: * * > -- spawn 16km from L.A. when in Sol system * > local earth = Space.GetBody(3) * > local ship = Space.SpawnShipLanded("viper_police", earth, math.deg2rad(34.06473923), math.deg2rad(-118.1591568)) * * Availability: * * July 2013 * * Status: * * experimental */ static int l_space_spawn_ship_landed(lua_State *l) { if (!Pi::game) luaL_error(l, "Game is not started"); LUA_DEBUG_START(l); const char *type = luaL_checkstring(l, 1); if (! ShipType::Get(type)) luaL_error(l, "Unknown ship type '%s'", type); Planet *planet = LuaObject<Planet>::CheckFromLua(2); if (planet->GetSystemBody()->GetSuperType() != SystemBody::SUPERTYPE_ROCKY_PLANET) luaL_error(l, "Body is not a rocky planet"); float latitude = luaL_checknumber(l, 3); float longitude = luaL_checknumber(l, 4); Ship *ship = new Ship(type); assert(ship); Pi::game->GetSpace()->AddBody(ship); ship->SetLandedOn(planet, latitude, longitude); LuaObject<Ship>::PushToLua(ship); LUA_DEBUG_END(l, 1); return 1; }
// 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); }
void Ship::StaticUpdate(const float timeStep) { // do player sounds before dead check, so they also turn off if (IsType(Object::PLAYER)) DoThrusterSounds(); if (IsDead()) return; if (m_controller) m_controller->StaticUpdate(timeStep); if (GetHullTemperature() > 1.0) Explode(); UpdateAlertState(); /* FUEL SCOOPING!!!!!!!!! */ int capacity = 0; Properties().Get("fuel_scoop_cap", capacity); if (m_flightState == FLYING && capacity > 0) { Body *astro = GetFrame()->GetBody(); if (astro && astro->IsType(Object::PLANET)) { Planet *p = static_cast<Planet*>(astro); if (p->GetSystemBody()->IsScoopable()) { double dist = GetPosition().Length(); double pressure, density; p->GetAtmosphericState(dist, &pressure, &density); double speed = GetVelocity().Length(); vector3d vdir = GetVelocity().Normalized(); vector3d pdir = -GetOrient().VectorZ(); double dot = vdir.Dot(pdir); if ((m_stats.free_capacity) && (dot > 0.95) && (speed > 2000.0) && (density > 1.0)) { double rate = speed*density*0.00000333f*double(capacity); if (Pi::rng.Double() < rate) { lua_State *l = Lua::manager->GetLuaState(); pi_lua_import(l, "Equipment"); LuaTable hydrogen = LuaTable(l, -1).Sub("cargo").Sub("hydrogen"); LuaObject<Ship>::CallMethod(this, "AddEquip", hydrogen); UpdateEquipStats(); if (this->IsType(Object::PLAYER)) { Pi::game->log->Add(stringf(Lang::FUEL_SCOOP_ACTIVE_N_TONNES_H_COLLECTED, formatarg("quantity", LuaObject<Ship>::CallMethod<int>(this, "CountEquip", hydrogen)))); } lua_pop(l, 3); } } } } } // Cargo bay life support capacity = 0; Properties().Get("cargo_life_support_cap", capacity); if (!capacity) { // Hull is pressure-sealed, it just doesn't provide // temperature regulation and breathable atmosphere // kill stuff roughly every 5 seconds if ((!m_dockedWith) && (5.0*Pi::rng.Double() < timeStep)) { std::string t(Pi::rng.Int32(2) ? "live_animals" : "slaves"); lua_State *l = Lua::manager->GetLuaState(); pi_lua_import(l, "Equipment"); LuaTable cargo = LuaTable(l, -1).Sub("cargo"); if (LuaObject<Ship>::CallMethod<int>(this, "RemoveEquip", cargo.Sub(t))) { LuaObject<Ship>::CallMethod<int>(this, "AddEquip", cargo.Sub("fertilizer")); if (this->IsType(Object::PLAYER)) { Pi::game->log->Add(Lang::CARGO_BAY_LIFE_SUPPORT_LOST); } lua_pop(l, 4); } else lua_pop(l, 3); } } if (m_flightState == FLYING) m_launchLockTimeout -= timeStep; if (m_launchLockTimeout < 0) m_launchLockTimeout = 0; if (m_flightState == JUMPING || m_flightState == HYPERSPACE) m_launchLockTimeout = 0; // lasers for (int i=0; i<ShipType::GUNMOUNT_MAX; i++) { m_gun[i].recharge -= timeStep; float rateCooling = 0.01f; float cooler = 1.0f; Properties().Get("laser_cooler_cap", cooler); rateCooling *= cooler; m_gun[i].temperature -= rateCooling*timeStep; if (m_gun[i].temperature < 0.0f) m_gun[i].temperature = 0; if (m_gun[i].recharge < 0.0f) m_gun[i].recharge = 0; if (!m_gun[i].state) continue; if (m_gun[i].recharge > 0.0f) continue; if (m_gun[i].temperature > 1.0) continue; FireWeapon(i); } if (m_ecmRecharge > 0.0f) { m_ecmRecharge = std::max(0.0f, m_ecmRecharge - timeStep); } if (m_shieldCooldown > 0.0f) { m_shieldCooldown = std::max(0.0f, m_shieldCooldown - timeStep); } if (m_stats.shield_mass_left < m_stats.shield_mass) { // 250 second recharge float recharge_rate = 0.004f; float booster = 1.0f; Properties().Get("shield_energy_booster_cap", booster); recharge_rate *= booster; m_stats.shield_mass_left = Clamp(m_stats.shield_mass_left + m_stats.shield_mass * recharge_rate * timeStep, 0.0f, m_stats.shield_mass); Properties().Set("shieldMassLeft", m_stats.shield_mass_left); } if (m_wheelTransition) { m_wheelState += m_wheelTransition*0.3f*timeStep; m_wheelState = Clamp(m_wheelState, 0.0f, 1.0f); if (is_equal_exact(m_wheelState, 0.0f) || is_equal_exact(m_wheelState, 1.0f)) m_wheelTransition = 0; } if (m_testLanded) TestLanded(); capacity = 0; Properties().Get("hull_autorepair_cap", capacity); if (capacity) { m_stats.hull_mass_left = std::min(m_stats.hull_mass_left + 0.1f*timeStep, float(m_type->hullMass)); Properties().Set("hullMassLeft", m_stats.hull_mass_left); Properties().Set("hullPercent", 100.0f * (m_stats.hull_mass_left / float(m_type->hullMass))); } // After calling StartHyperspaceTo this Ship must not spawn objects // holding references to it (eg missiles), as StartHyperspaceTo // removes the ship from Space::bodies and so the missile will not // have references to this cleared by NotifyRemoved() if (m_hyperspace.now) { m_hyperspace.now = false; EnterHyperspace(); } if (m_hyperspace.countdown > 0.0f) { // Check the Lua function bool abort = false; lua_State * l = m_hyperspace.checks.GetLua(); if (l) { m_hyperspace.checks.PushCopyToStack(); if (lua_isfunction(l, -1)) { lua_call(l, 0, 1); abort = !lua_toboolean(l, -1); lua_pop(l, 1); } } if (abort) { AbortHyperjump(); } else { m_hyperspace.countdown = m_hyperspace.countdown - timeStep; if (!abort && m_hyperspace.countdown <= 0.0f) { m_hyperspace.countdown = 0; m_hyperspace.now = true; SetFlightState(JUMPING); // We have to fire it here, because the event isn't actually fired until // after the whole physics update, which means the flight state on next // step would be HYPERSPACE, thus breaking quite a few things. LuaEvent::Queue("onLeaveSystem", this); } } } //Add smoke trails for missiles on thruster state static double s_timeAccum = 0.0; s_timeAccum += timeStep; if (m_type->tag == ShipType::TAG_MISSILE && !is_equal_exact(m_thrusters.LengthSqr(), 0.0) && (s_timeAccum > 4 || 0.1*Pi::rng.Double() < timeStep)) { s_timeAccum = 0.0; const vector3d pos = GetOrient() * vector3d(0, 0 , 5); const float speed = std::min(10.0*GetVelocity().Length()*std::max(1.0,fabs(m_thrusters.z)),100.0); SfxManager::AddThrustSmoke(this, speed, pos); } }
/* * Function: SpawnShipLandedNear * * Create a ship and place it on the surface near the given <Body>. * * > ship = Space.SpawnShipLandedNear(type, body, min, max) * * Parameters: * * type - the name of the ship * * body - the <Body> near which the ship should be spawned. It must be on the ground or close to it, * i.e. it must be in the rotating frame of the planetary body. * * min - minimum distance from the surface point below the body to place the ship, in Km * * max - maximum distance to place the ship * * Return: * * ship - a <Ship> object for the new ship * * Example: * * > -- spawn a ship 10km from the player * > local ship = Ship.SpawnShipLandedNear("viper_police", Game.player, 10, 10) * * Availability: * * July 2013 * * Status: * * experimental */ static int l_space_spawn_ship_landed_near(lua_State *l) { if (!Pi::game) luaL_error(l, "Game is not started"); LUA_DEBUG_START(l); const char *type = luaL_checkstring(l, 1); if (! ShipType::Get(type)) luaL_error(l, "Unknown ship type '%s'", type); Body *nearbody = LuaObject<Body>::CheckFromLua(2); const float min_dist = luaL_checknumber(l, 3); const float max_dist = luaL_checknumber(l, 4); if (min_dist > max_dist) luaL_error(l, "min_dist must not be larger than max_dist"); Ship *ship = new Ship(type); assert(ship); // XXX protect against spawning inside the body Frame * newframe = nearbody->GetFrame()->GetRotFrame(); if (!newframe->IsRotFrame()) luaL_error(l, "Body must be in rotating frame"); SystemBody *sbody = newframe->GetSystemBody(); if (sbody->GetSuperType() != SystemBody::SUPERTYPE_ROCKY_PLANET) luaL_error(l, "Body is not on a rocky planet"); if (max_dist > sbody->GetRadius()) luaL_error(l, "max_dist too large for planet radius"); // We assume that max_dist is much smaller than the planet radius, i.e. that our area is reasonably flat // So, we const vector3d up = nearbody->GetPosition().Normalized(); vector3d x; vector3d y; // Calculate a orthonormal basis for a horizontal plane. For numerical reasons we do that determining the smallest // coordinate and take the cross product with (1,0,0), (0,1,0) or (0,0,1) respectively to calculate the first vector. // The second vector is just the cross product of the up-vector and out first vector. if (up.x <= up.y && up.x <= up.z) { x = vector3d(0.0, up.z, -up.y).Normalized(); y = vector3d(-up.y*up.y - up.z*up.z, up.x*up.y, up.x*up.z).Normalized(); } else if (up.y <= up.x && up.y <= up.z) { x = vector3d(-up.z, 0.0, up.x).Normalized(); y = vector3d(up.x*up.y, -up.x*up.x - up.z*up.z, up.y*up.z).Normalized(); } else { x = vector3d(up.y, -up.x, 0.0).Normalized(); y = vector3d(up.x*up.z, up.y*up.z, -up.x*up.x - up.y*up.y).Normalized(); } Planet *planet = static_cast<Planet*>(newframe->GetBody()); const double radius = planet->GetSystemBody()->GetRadius(); const vector3d planar = MathUtil::RandomPointInCircle(min_dist * 1000.0, max_dist * 1000.0); vector3d pos = (radius * up + x * planar.x + y * planar.y).Normalized(); float latitude = atan2(pos.y, sqrt(pos.x*pos.x + pos.z * pos.z)); float longitude = atan2(pos.x, pos.z); Pi::game->GetSpace()->AddBody(ship); ship->SetLandedOn(planet, latitude, longitude); LuaObject<Ship>::PushToLua(ship); LUA_DEBUG_END(l, 1); return 1; }
void Ship::StaticUpdate(const float timeStep) { // do player sounds before dead check, so they also turn off if (IsType(Object::PLAYER)) DoThrusterSounds(); if (IsDead()) return; if (m_controller) m_controller->StaticUpdate(timeStep); if (GetHullTemperature() > 1.0) Explode(); UpdateAlertState(); /* FUEL SCOOPING!!!!!!!!! */ if ((m_flightState == FLYING) && (m_equipment.Get(Equip::SLOT_FUELSCOOP) != Equip::NONE)) { Body *astro = GetFrame()->GetBody(); if (astro && astro->IsType(Object::PLANET)) { Planet *p = static_cast<Planet*>(astro); if (p->GetSystemBody()->IsScoopable()) { double dist = GetPosition().Length(); double pressure, density; p->GetAtmosphericState(dist, &pressure, &density); double speed = GetVelocity().Length(); vector3d vdir = GetVelocity().Normalized(); vector3d pdir = -GetOrient().VectorZ(); double dot = vdir.Dot(pdir); if ((m_stats.free_capacity) && (dot > 0.95) && (speed > 2000.0) && (density > 1.0)) { double rate = speed*density*0.00001f; if (Pi::rng.Double() < rate) { m_equipment.Add(Equip::HYDROGEN); UpdateEquipStats(); if (this->IsType(Object::PLAYER)) { Pi::Message(stringf(Lang::FUEL_SCOOP_ACTIVE_N_TONNES_H_COLLECTED, formatarg("quantity", m_equipment.Count(Equip::SLOT_CARGO, Equip::HYDROGEN)))); } } } } } } // Cargo bay life support if (m_equipment.Get(Equip::SLOT_CARGOLIFESUPPORT) != Equip::CARGO_LIFE_SUPPORT) { // Hull is pressure-sealed, it just doesn't provide // temperature regulation and breathable atmosphere // kill stuff roughly every 5 seconds if ((!m_dockedWith) && (5.0*Pi::rng.Double() < timeStep)) { Equip::Type t = (Pi::rng.Int32(2) ? Equip::LIVE_ANIMALS : Equip::SLAVES); if (m_equipment.Remove(t, 1)) { m_equipment.Add(Equip::FERTILIZER); if (this->IsType(Object::PLAYER)) { Pi::Message(Lang::CARGO_BAY_LIFE_SUPPORT_LOST); } } } } if (m_flightState == FLYING) m_launchLockTimeout -= timeStep; if (m_launchLockTimeout < 0) m_launchLockTimeout = 0; // lasers for (int i=0; i<ShipType::GUNMOUNT_MAX; i++) { m_gunRecharge[i] -= timeStep; float rateCooling = 0.01f; if (m_equipment.Get(Equip::SLOT_LASERCOOLER) != Equip::NONE) { rateCooling *= float(Equip::types[ m_equipment.Get(Equip::SLOT_LASERCOOLER) ].pval); } m_gunTemperature[i] -= rateCooling*timeStep; if (m_gunTemperature[i] < 0.0f) m_gunTemperature[i] = 0; if (m_gunRecharge[i] < 0.0f) m_gunRecharge[i] = 0; if (!m_gunState[i]) continue; if (m_gunRecharge[i] > 0.0f) continue; if (m_gunTemperature[i] > 1.0) continue; FireWeapon(i); } if (m_ecmRecharge > 0.0f) { m_ecmRecharge = std::max(0.0f, m_ecmRecharge - timeStep); } if (m_stats.shield_mass_left < m_stats.shield_mass) { // 250 second recharge float recharge_rate = 0.004f; if (m_equipment.Get(Equip::SLOT_ENERGYBOOSTER) != Equip::NONE) { recharge_rate *= float(Equip::types[ m_equipment.Get(Equip::SLOT_ENERGYBOOSTER) ].pval); } m_stats.shield_mass_left += m_stats.shield_mass * recharge_rate * timeStep; } m_stats.shield_mass_left = Clamp(m_stats.shield_mass_left, 0.0f, m_stats.shield_mass); if (m_wheelTransition) { m_wheelState += m_wheelTransition*0.3f*timeStep; m_wheelState = Clamp(m_wheelState, 0.0f, 1.0f); if (is_equal_exact(m_wheelState, 0.0f) || is_equal_exact(m_wheelState, 1.0f)) m_wheelTransition = 0; } if (m_testLanded) TestLanded(); if (m_equipment.Get(Equip::SLOT_HULLAUTOREPAIR) == Equip::HULL_AUTOREPAIR) { const ShipType &stype = GetShipType(); m_stats.hull_mass_left = std::min(m_stats.hull_mass_left + 0.1f*timeStep, float(stype.hullMass)); } // After calling StartHyperspaceTo this Ship must not spawn objects // holding references to it (eg missiles), as StartHyperspaceTo // removes the ship from Space::bodies and so the missile will not // have references to this cleared by NotifyRemoved() if (m_hyperspace.countdown > 0.0f) { m_hyperspace.countdown = m_hyperspace.countdown - timeStep; if (m_hyperspace.countdown <= 0.0f) { m_hyperspace.countdown = 0; m_hyperspace.now = true; } } if (m_hyperspace.now) { m_hyperspace.now = false; EnterHyperspace(); } }
static Frame *MakeFrameFor(SystemBody *sbody, Body *b, Frame *f) { Frame *orbFrame, *rotFrame; double frameRadius; if (!sbody->parent) { if (b) b->SetFrame(f); f->m_sbody = sbody; f->m_astroBody = b; return f; } if (sbody->type == SystemBody::TYPE_GRAVPOINT) { orbFrame = new Frame(f, sbody->name.c_str()); orbFrame->m_sbody = sbody; orbFrame->m_astroBody = b; orbFrame->SetRadius(sbody->GetMaxChildOrbitalDistance()*1.1); return orbFrame; } SystemBody::BodySuperType supertype = sbody->GetSuperType(); if ((supertype == SystemBody::SUPERTYPE_GAS_GIANT) || (supertype == SystemBody::SUPERTYPE_ROCKY_PLANET)) { // for planets we want an non-rotating frame for a few radii // and a rotating frame in the same position but with maybe 1.05*radius, // which actually contains the object. frameRadius = std::max(4.0*sbody->GetRadius(), sbody->GetMaxChildOrbitalDistance()*1.05); orbFrame = new Frame(f, sbody->name.c_str()); orbFrame->m_sbody = sbody; orbFrame->SetRadius(frameRadius); //printf("\t\t\t%s has frame size %.0fkm, body radius %.0fkm\n", sbody->name.c_str(), // (frameRadius ? frameRadius : 10*sbody->GetRadius())*0.001f, // sbody->GetRadius()*0.001f); assert(sbody->rotationPeriod != 0); rotFrame = new Frame(orbFrame, sbody->name.c_str()); // rotating frame has size of GeoSphere terrain bounding sphere rotFrame->SetRadius(b->GetBoundingRadius()); rotFrame->SetAngVelocity(vector3d(0,2*M_PI/sbody->GetRotationPeriod(),0)); rotFrame->m_astroBody = b; SetFrameOrientationFromSystemBodyAxialTilt(rotFrame, sbody); b->SetFrame(rotFrame); return orbFrame; } else if (supertype == SystemBody::SUPERTYPE_STAR) { // stars want a single small non-rotating frame orbFrame = new Frame(f, sbody->name.c_str()); orbFrame->m_sbody = sbody; orbFrame->m_astroBody = b; orbFrame->SetRadius(sbody->GetMaxChildOrbitalDistance()*1.1); b->SetFrame(orbFrame); return orbFrame; } else if (sbody->type == SystemBody::TYPE_STARPORT_ORBITAL) { // space stations want non-rotating frame to some distance // and a much closer rotating frame frameRadius = 1000000.0; // XXX NFI! orbFrame = new Frame(f, sbody->name.c_str()); orbFrame->m_sbody = sbody; // orbFrame->SetRadius(10*sbody->GetRadius()); orbFrame->SetRadius(frameRadius); assert(sbody->rotationPeriod != 0); rotFrame = new Frame(orbFrame, sbody->name.c_str()); rotFrame->SetRadius(1000.0); // rotFrame->SetRadius(1.1*sbody->GetRadius()); // enough for collisions? rotFrame->SetAngVelocity(vector3d(0.0,double(static_cast<SpaceStation*>(b)->GetDesiredAngVel()),0.0)); rotFrame->m_astroBody = b; // hope this doesn't break anything b->SetFrame(rotFrame); return orbFrame; } else if (sbody->type == SystemBody::TYPE_STARPORT_SURFACE) { // just put body into rotating frame of planet, not in its own frame // (because collisions only happen between objects in same frame, // and we want collisions on starport and on planet itself) Frame *frame = *f->m_children.begin(); b->SetFrame(frame); assert(frame->m_astroBody->IsType(Object::PLANET)); Planet *planet = static_cast<Planet*>(frame->m_astroBody); /* position on planet surface */ double height; int tries; matrix4x4d rot; vector3d pos; // first try suggested position rot = sbody->orbit.rotMatrix; pos = rot * vector3d(0,1,0); if (planet->GetTerrainHeight(pos) - planet->GetSystemBody()->GetRadius() <= 0.0) { MTRand r(sbody->seed); // position is under water. try some random ones for (tries=0; tries<100; tries++) { // used for orientation on planet surface double r2 = r.Double(); // function parameter evaluation order is implementation-dependent double r1 = r.Double(); // can't put two rands in the same expression rot = matrix4x4d::RotateZMatrix(2*M_PI*r1) * matrix4x4d::RotateYMatrix(2*M_PI*r2); pos = rot * vector3d(0,1,0); height = planet->GetTerrainHeight(pos) - planet->GetSystemBody()->GetRadius(); // don't want to be under water if (height > 0.0) break; } } b->SetPosition(pos * planet->GetTerrainHeight(pos)); b->SetRotMatrix(rot); return frame; } else { assert(0); } return NULL; }