particles.h

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/*
Copyright (c) 2019-2024 Alexander Scholz
 
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
 
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
 
1. The origin of this software must not be misrepresented; you must not
   claim that you wrote the original software. If you use this software
   in a product, an acknowledgment in the product documentation would be
   appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
#ifndef YOURGAME_PARTICLES_H
#define YOURGAME_PARTICLES_H
 
#include <vector>
#include <random>
#include <ctime>
#include <glm/glm.hpp>
 
namespace yourgame
{
    namespace math
    {
        class Particles
        {
        public:
            struct Config
            {
                size_t count = 100;                                                
                unsigned int seed = static_cast<unsigned int>(std::time(nullptr)); 
                bool scatterOnInit = true;                                         
                bool scatterOnSpawn = false;                                       
                bool respawn = true;                                               
                glm::vec3 origin = {0.0f, 0.0f, 0.0f};                             
                glm::vec3 emitterA = {0.0f, 0.0f, 0.0f};                           
                glm::vec3 emitterB = {0.0f, 0.0f, 0.0f};                           
                glm::vec3 emitterC = {0.0f, 0.0f, 0.0f};                           
                glm::vec3 baseDirection = {0.0f, 1.0f, 0.0f};                      
                glm::vec3 noisDirection = {0.2f, 0.2f, 0.2f};                      
                float baseVelocity = 1.5f;                                         
                float noisVelocity = 0.2f;                                         
                float baseLifetime = 3.0f;                                         
                float noisLifetime = 0.4f;                                         
            };
 
            Particles(const Config cfg);
 
            virtual void tick(float dt);
            void reset();
            Config m_cfg;
            std::vector<glm::vec4> m_positionData;
            std::vector<float> m_progressData;
 
        private:
            struct Part
            {
                glm::vec3 pos;
                glm::vec3 move;
                float lifetime;
                float totalLifeInv;
                float progress;
            };
            std::default_random_engine m_rndgen;
            std::uniform_real_distribution<float> m_unirnd;
            std::vector<Part> m_parts;
            Part spawn();
            float rnd1();
        };
    } // namespace math
} // namespace yourgame
 
#endif