#include <cmath> #include <cstdlib> #include <ctime> #include "../api/ParticleEmitter.h" #include "../api/Transform.h" #include "../manager/ComponentManager.h" #include "ParticleSystem.h" using namespace crepe; void ParticleSystem::update() { // Get all emitters ComponentManager & mgr = this->mediator.component_manager; RefVector<ParticleEmitter> emitters = mgr.get_components_by_type<ParticleEmitter>(); for (ParticleEmitter & emitter : emitters) { // Get transform linked to emitter const Transform & transform = mgr.get_components_by_id<Transform>(emitter.game_object_id).front().get(); // Emit particles based on emission_rate int updates = calculate_update(this->update_count, emitter.data.emission_rate); for (size_t i = 0; i < updates; i++) { emit_particle(emitter, transform); } // Update all particles for (Particle & particle : emitter.data.particles) { if (particle.active) { particle.update(); } } // Check if within boundary check_bounds(emitter, transform); } this->update_count = (this->update_count + 1) % this->MAX_UPDATE_COUNT; } void ParticleSystem::emit_particle(ParticleEmitter & emitter, const Transform & transform) { constexpr float DEG_TO_RAD = M_PI / 180.0; vec2 initial_position = emitter.data.position + transform.position; float random_angle = generate_random_angle(emitter.data.min_angle, emitter.data.max_angle); float random_speed = generate_random_speed(emitter.data.min_speed, emitter.data.max_speed); float angle_radians = random_angle * DEG_TO_RAD; vec2 velocity = {random_speed * std::cos(angle_radians), random_speed * std::sin(angle_radians)}; for (Particle & particle : emitter.data.particles) { if (!particle.active) { particle.reset(emitter.data.end_lifespan, initial_position, velocity, random_angle); break; } } } int ParticleSystem::calculate_update(int count, double emission) const { double integer_part = std::floor(emission); double fractional_part = emission - integer_part; if (fractional_part > 0) { int denominator = static_cast<int>(1.0 / fractional_part); return (count % denominator == 0) ? 1 : 0; } return static_cast<int>(emission); } void ParticleSystem::check_bounds(ParticleEmitter & emitter, const Transform & transform) { vec2 offset = emitter.data.boundary.offset + transform.position + emitter.data.position; double half_width = emitter.data.boundary.width / 2.0; double half_height = emitter.data.boundary.height / 2.0; const double LEFT = offset.x - half_width; const double RIGHT = offset.x + half_width; const double TOP = offset.y - half_height; const double BOTTOM = offset.y + half_height; for (Particle & particle : emitter.data.particles) { const vec2 & position = particle.position; bool within_bounds = (position.x >= LEFT && position.x <= RIGHT && position.y >= TOP && position.y <= BOTTOM); if (!within_bounds) { if (emitter.data.boundary.reset_on_exit) { particle.active = false; } else { particle.velocity = {0, 0}; if (position.x < LEFT) particle.position.x = LEFT; else if (position.x > RIGHT) particle.position.x = RIGHT; if (position.y < TOP) particle.position.y = TOP; else if (position.y > BOTTOM) particle.position.y = BOTTOM; } } } } double ParticleSystem::generate_random_angle(double min_angle, double max_angle) const { if (min_angle == max_angle) { return min_angle; } else if (min_angle < max_angle) { return min_angle + static_cast<double>(std::rand() % static_cast<int>(max_angle - min_angle)); } else { double angle_offset = (360 - min_angle) + max_angle; double random_angle = min_angle + static_cast<double>(std::rand() % static_cast<int>(angle_offset)); return (random_angle >= 360) ? random_angle - 360 : random_angle; } } double ParticleSystem::generate_random_speed(double min_speed, double max_speed) const { if (min_speed == max_speed) { return min_speed; } else { return min_speed + static_cast<double>(std::rand() % static_cast<int>(max_speed - min_speed)); } }