particle.cpp

#include "particle.h"
 
using namespace sgltk;
 
Particles::Particles() {
    timer.start();
}
 
Particles::~Particles() {
}
 
void Particles::resize(unsigned int number) {
    this->number = number;
    position.resize(number);
    velocity.resize(number);
    lifetime.resize(number);
    indices.resize(number);
    for(unsigned int i = 0; i < number; i++) {
        indices[i] = i;
    }
    pos_buf = mesh.attach_vertex_buffer(position, GL_STREAM_DRAW);
    vel_buf = mesh.attach_vertex_buffer(velocity, GL_STREAM_DRAW);
    life_buf = mesh.attach_vertex_buffer(lifetime, GL_STREAM_DRAW);
    mesh.attach_index_buffer(indices);
    mesh.set_vertex_attribute("position_in", pos_buf, 3, GL_FLOAT, 0, 0);
    mesh.set_vertex_attribute("velocity_in", vel_buf, 3, GL_FLOAT, 0, 0);
    mesh.set_vertex_attribute("lifetime_in", life_buf, 2, GL_FLOAT, 0, 0);
}
 
void Particles::setup_shader(Shader *shader) {
    mesh.setup_shader(shader);
}
 
void Particles::setup_camera(Camera *camera) {
    mesh.setup_camera(camera);
}
 
void Particles::setup_camera(glm::mat4 *view_matrix,
                glm::mat4 *projection_matrix) {
 
    mesh.setup_camera(view_matrix, projection_matrix);
}
 
void Particles::attach_texture(const std::string& name,
                   const Texture& texture) {
 
    mesh.attach_texture(name, texture);
}
 
bool Particles::add_particle(glm::vec3 position,
                glm::vec3 velocity,
                float lifetime) {
 
    float time = (float)timer.get_time_s();
    for(unsigned int i = 0; i < number; i++) {
        if(this->lifetime[i][0] + this->lifetime[i][1] < time) {
            this->position[i] = position;
            this->velocity[i] = velocity;
            this->lifetime[i] = glm::vec2(time, lifetime);
            break;
        }
    }
    return true;
}
 
bool Particles::add_particle_immediately(glm::vec3 position,
                    glm::vec3 velocity,
                    float lifetime) {
 
    float time = (float)timer.get_time_s();
    for(unsigned int i = 0; i < number; i++) {
        if(this->lifetime[i][0] + this->lifetime[i][1] < time) {
            this->position[i] = position;
            this->velocity[i] = velocity;
            this->lifetime[i] = glm::vec2(time, lifetime);
            mesh.replace_partial_data(pos_buf, i * sizeof(glm::vec3), &this->position[i], 1);
            mesh.replace_partial_data(vel_buf, i * sizeof(glm::vec3), &this->velocity[i], 1);
            mesh.replace_partial_data(life_buf, i * sizeof(glm::vec2), &this->lifetime[i], 1);
            mesh.set_vertex_attribute("position_in", pos_buf, 3, GL_FLOAT, 0, 0);
            mesh.set_vertex_attribute("velocity_in", vel_buf, 3, GL_FLOAT, 0, 0);
            mesh.set_vertex_attribute("lifetime_in", life_buf, 2, GL_FLOAT, 0, 0);
            break;
        }
    }
    return true;
}
 
void Particles::update_all() {
    mesh.replace_buffer_data(pos_buf, position);
    mesh.replace_buffer_data(vel_buf, velocity);
    mesh.replace_buffer_data(life_buf, lifetime);
    mesh.set_vertex_attribute("position_in", pos_buf, 3, GL_FLOAT, 0, 0);
    mesh.set_vertex_attribute("velocity_in", vel_buf, 3, GL_FLOAT, 0, 0);
    mesh.set_vertex_attribute("lifetime_in", life_buf, 2, GL_FLOAT, 0, 0);
}
 
void Particles::draw() {
    if(!mesh.shader) {
        App::error_string.push_back("No shader set.");
    }
    mesh.shader->bind();
    mesh.shader->set_uniform("time", static_cast<float>(timer.get_time_s()));
    mesh.draw(GL_POINTS);
}