live_particles.h

#pragma once
 
#include <cstdint>
#include <unordered_map>
#include <vector>
 
#include <glm/glm.hpp>
 
#include "ecs/entity.h"
 
namespace Vkm::Engine {

struct Particle {
    glm::vec3 position{0.0f};  
    glm::vec3 velocity{0.0f};  
    float     age      = 0.0f; 
    float     lifetime = 1.0f; 
};

struct LiveParticles {
    struct Pool {
        EntityId              emitter;
        std::vector<Particle> particles;
        float                 spawnAccumulator = 0.0f;  
        uint64_t              seen = 0;                 
    };
 
    std::unordered_map<uint32_t, Pool> pools;  

    const std::vector<Particle>* of(EntityId emitter) const {
        const auto found = pools.find(emitter.slot());
        if (found == pools.end() || found->second.emitter != emitter) return nullptr;
        return &found->second.particles;
    }
};
 
} // namespace Vkm::Engine