Function loadParticleSystem

src/Skybolt/SkyboltEngine/EntityFactory.cpp:285–330

}

static void loadParticleSystem(Entity* entity, const EntityFactory::Context& context, const EntityFactory::VisContext& visContext, const VisObjectsComponentPtr& visObjectsComponent, const SimVisBindingsComponentPtr& simVisBindingComponent, const nlohmann::json& json)
{
	NearestPlanetProvider nearestPlanetProvider = [world = context.simWorld] (const Vector3& position) {
		return findNearestEntityWithComponent<sim::PlanetComponent>(world->getEntities(), position).get();
	};

	ParticleEmitter::Params emitterParams;
	emitterParams.emissionRate = json.at("emissionRate");
	emitterParams.radius = json.at("radius");
	emitterParams.positionable = entity->getFirstComponentRequired<Node>();
	emitterParams.elevationAngle = DoubleRangeInclusive(json.at("elevationAngleMin"), json.at("elevationAngleMax"));
	emitterParams.speed = DoubleRangeInclusive(json.at("speedMin"), json.at("speedMax"));
	emitterParams.upDirection = readVector3(json.at("upDirection"));
	emitterParams.random = std::make_shared<Random>(/* seed */ 0);
	emitterParams.temperatureDegreesCelcius = readOptionalOrDefault(json, "initialTemperatureDegreesCelcius", 0.0);
	emitterParams.zeroAtmosphericDensityAlpha = readOptionalOrDefault(json, "zeroAtmosphericDensityAlpha", 1.0);
	emitterParams.earthSeaLevelAtmosphericDensityAlpha = readOptionalOrDefault(json, "earthSeaLevelAtmosphericDensityAlpha", 1.0);
	emitterParams.nearestPlanetProvider = nearestPlanetProvider;

	double lifetime = json.at("lifetime");

	ParticleIntegrator::Params integratorParams;
	integratorParams.lifetime = lifetime;
	integratorParams.radiusLinearGrowthPerSecond = json.at("radiusLinearGrowthPerSecond");
	integratorParams.atmosphericSlowdownFactor = json.at("atmosphericSlowdownFactor");
	integratorParams.heatTransferCoefficent = readOptional<float>(json, "heatTransferCoefficent");
	integratorParams.nearestPlanetProvider = nearestPlanetProvider;

	auto particleSystem = std::make_shared<ParticleSystem>(ParticleSystem::Operations({
		std::make_shared<ParticleIntegrator>(integratorParams), // integrate before emission ensure new particles emitted at end of time step
		std::make_shared<ParticleEmitter>(emitterParams),
		std::make_shared<ParticleKiller>(lifetime)
	}));
	entity->addComponent(std::make_shared<ParticleSystemComponent>(particleSystem));

	osg::ref_ptr<osg::Texture2D> texture = visContext.textureCache->getOrCreateTexture(json.at("albedoTexture"), [](const std::string& filename) {
		return vis::createTilingSrgbTexture(osgDB::readImageFile(filename));
	});

	auto program = visContext.programs->getRequiredProgram("particles");
	auto visParticles = std::make_shared<vis::Particles>(program, texture);
	visObjectsComponent->addObject(visParticles);

	SimVisBindingPtr binding(new ParticlesVisBinding(particleSystem, visParticles));
	simVisBindingComponent->bindings.push_back(binding);
}

struct PlanetStatsUpdater : vis::PlanetFeaturesListener, vis::QuadTreeTileLoaderListener, sim::Component
{