From 24bf28a8fb9cc8c3a90b77de9b60728bece7885d Mon Sep 17 00:00:00 2001
From: "Claudius \"keldu\" Holeksa" <mail@keldu.de>
Date: Sat, 18 Oct 2025 18:01:14 +0200
Subject: Moving project structure for more less compilation

---
 lib/c++/particle/particle.hpp | 113 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 113 insertions(+)
 create mode 100644 lib/c++/particle/particle.hpp

(limited to 'lib/c++/particle/particle.hpp')

diff --git a/lib/c++/particle/particle.hpp b/lib/c++/particle/particle.hpp
new file mode 100644
index 0000000..39aadfb
--- /dev/null
+++ b/lib/c++/particle/particle.hpp
@@ -0,0 +1,113 @@
+#pragma once
+
+#include <forstio/codec/data.hpp>
+#include <forstio/codec/data_math.hpp>
+#include <forstio/codec/math.hpp>
+
+namespace kel {
+namespace lbm {
+namespace sch {
+using namespace saw::schema;
+
+template<typename T, uint64_t D>
+using ParticleRigidBody = Struct<
+	Member<Vector<T,D>, "position">,
+	Member<Vector<T,D>, "position_old">,
+	Member<T, "rotation">,
+	Member<T, "rotation_old">,
+
+	Member<Vector<T,D>, "acceleration">,
+	Member<T, "rotational_acceleration">
+>;
+
+template<typename T, uint64_t D>
+using ParticleMask = Struct<
+	Member<Array<T,D>, "grid">,
+	Member<Vector<T,D>, "center_of_mass">
+>;
+
+template<typename T, uint64_t D>
+using Particle = Struct<
+	Member<ParticleRigidBody<T,D>, "rigid_body">,
+	Member<ParticleMask<T,D>, "mask">,
+	Member<T, "mass">,
+	Member<T, "size">
+>;
+}
+
+template<typename T, uint64_t D, typename ParticleCollision = sch::ParticleMask<T,D> >
+class particle_system {
+private:
+	saw::data<sch::Array<sch::Particle<T,D>>> particles_;
+
+	void verlet_step(saw::data<sch::Particle<T,D>>& particle, saw::data<T> time_step_delta){
+		auto& body = particle.template get<"rigid_body">();
+
+		auto& pos = body.template get<"position">();
+		auto& pos_old = body.template get<"position_old">();
+
+		// auto& rot = body.template get<"rotation">();
+		auto& acc = body.template get<"acceleration">();
+
+		auto tsd_squared = time_step_delta * time_step_delta;
+
+		saw::data<sch::Vector<T,D>> pos_new;
+		// Actual step
+		for(uint64_t i = 0u; i < D; ++i){
+			pos_new.at({{i}}) = saw::data<T>{2.0} * pos.at({{i}}) - pos_old.at({{i}}) + acc.at({{i}}) * tsd_squared;
+		}
+
+		pos_old = pos;
+		pos = pos_new;
+	}
+public:
+	/**
+	 *  Add particle to this class and return an id representing this particle
+	 */
+	saw::error_or<saw::data<sch::UInt64>> add_particle(saw::data<sch::Particle<T,D>> particle__){
+		auto size = particles_.size();
+		auto eov = particles_.add(std::move(particle__));
+		if(eov.is_error()){
+			return std::move(eov.get_error());
+		}
+
+		return size;
+	}
+
+	/*
+	saw::data<sch::Particle<T,D>>& get_particle(saw::data<sch::UInt64> id){
+	}
+	*/
+
+	void step(saw::data<T> time_step_delta){
+		for(saw::data<sch::UInt64> i{0u}; i < particles_.size(); ++i){
+			verlet_step(particles_.at(i), time_step_delta);
+		}
+	}
+
+	template<typename LbmLattice>
+	void update_particle_border(saw::data<LbmLattice>& latt){
+		(void) latt;
+		for(auto& iter : particles_){
+			auto& par = iter;
+
+			auto& body = par.template get<"rigid_body">();
+			auto& size = par.template get<"size">();
+
+
+		}
+	}
+
+	saw::data<sch::UInt64> size() const {
+		return particles_.size();
+	}
+
+	/**
+	 * Mostly meant for unforeseen use cases.
+	 */
+	saw::data<sch::Particle<T,D>>& at(saw::data<sch::UInt64> i){
+		return particles_.at(i);
+	}
+};
+}
+}
-- 
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