particles.hpp

/*
 * MIT License
 *
 * Copyright (c) 2024 Giovanni Santini
 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 */
 
#pragma once
 
#define MAX_PARTICLES 1000
 
#include "camera.hpp"
#include "vao.hpp"
 
#include <glad/glad.h> /* OpenGL driver */
#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;
    int atlas;
    int atlas_width;
    int atlas_height;
    int atlas_index;
    types::vao vao;
 
    particle_emitter();
    particle_emitter(glm::vec3 starting_position, glm::vec3 starting_velocity,
                     glm::vec3 starting_spread, float starting_timeToLive,
                     int num_particles, float spawn_rate, float scale,
                     std::string atlas_path, int atlas_width, int atlas_height,
                     int atlas_index, camera *cam);
    ~particle_emitter();
 
    class builder;
 
    void update_particles(float deltaTime);
    void render_particles();
 
  private:
    camera *cam;
    void check_opengl_error(const std::string &functionName);
};
 
class particle_emitter::builder
{
  private:
    glm::vec3 starting_position = glm::vec3(0.0f, 0.0f, 0.0f);
    glm::vec3 starting_velocity = glm::vec3(0.0f, 0.0f, 0.0f);
    glm::vec3 starting_spread = glm::vec3(0.0f, 0.0f, 0.0f);
    float starting_time_to_live = 1.0f;
    int num_particles = MAX_PARTICLES;
    float spawn_rate = 0.01f;
    float scale = 1.0f;
    std::string atlas_path = "";
    int atlas_width = 8;
    int atlas_height = 8;
    int atlas_index = 0;
    camera *cam = nullptr;
 
  public:
    builder &set_starting_position(glm::vec3 starting_position);
    builder &set_starting_velocity(glm::vec3 starting_velocity);
    builder &set_starting_spread(glm::vec3 starting_spread);
    builder &set_starting_time_to_live(float starting_time_to_live);
    builder &set_num_particles(int num_particles);
    builder &set_spawn_rate(float spawn_rate);
    builder &set_scale(float scale);
    builder &set_atlas_path(std::string atlas_path);
    builder &set_atlas_width(int atlas_width);
    builder &set_atlas_height(int atlas_height);
    builder &set_atlas_index(int atlas_index);
    builder &set_camera(camera *cam);
 
    particle_emitter build();
};
 
} // namespace brenta