particles.hpp

// SPDX-License-Identifier: MIT
// Author:  Giovanni Santini
// Mail:    giovanni.santini@proton.me
// Github:  @San7o
 
#pragma once
 
#define MAX_PARTICLES 1000
 
#include <brenta/camera.hpp>
#include <brenta/texture.hpp>
#include <brenta/vao.hpp>
#include <glad/glad.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <string>
#include <vector>
 
namespace brenta
{
 
class particle_emitter
{
public:
  
  glm::vec3 starting_position;
  glm::vec3 starting_velocity;
  glm::vec3 starting_spread;
  float starting_time_to_live;
  int num_particles;
  float spawn_rate;
  float scale;
  types::buffer fbo[2];
  int current;
  texture atlas;
  int atlas_width;
  int atlas_height;
  int atlas_index;
  types::vao vao;
 
  struct config;
  class builder;
 
  static const config default_config;
 
  particle_emitter(config conf);
  
  void update_particles(float delta_time);
  void render_particles();
 
private:
  camera *cam;
};
 
struct particle_emitter::config
{
  glm::vec3 starting_position;
  glm::vec3 starting_velocity;
  glm::vec3 starting_spread;
  float starting_time_to_live;
  int num_particles;
  float spawn_rate;
  float scale;
  std::string atlas_path;
  int atlas_width;
  int atlas_height;
  int atlas_index;
  camera *cam;
};
  
class particle_emitter::builder
{
private:
 
  particle_emitter::config conf = particle_emitter::default_config;
 
public:
  builder &starting_position(glm::vec3 starting_position);
  builder &starting_velocity(glm::vec3 starting_velocity);
  builder &starting_spread(glm::vec3 starting_spread);
  builder &starting_time_to_live(float starting_time_to_live);
  builder &num_particles(int num_particles);
  builder &spawn_rate(float spawn_rate);
  builder &scale(float scale);
  builder &atlas_path(std::string atlas_path);
  builder &atlas_width(int atlas_width);
  builder &atlas_height(int atlas_height);
  builder &atlas_index(int atlas_index);
  builder &with_camera(camera *cam);
 
  particle_emitter build();
};
 
} // namespace brenta