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- /*
- * Copyright (C) 2017-2019 Christopher J. Howard
- *
- * This file is part of Antkeeper Source Code.
- *
- * Antkeeper Source Code is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * Antkeeper Source Code is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with Antkeeper Source Code. If not, see <http://www.gnu.org/licenses/>.
- */
-
- #include "steering-system.hpp"
-
- SteeringSystem::SteeringSystem(ComponentManager* componentManager):
- System(componentManager),
- boids(componentManager)
- {
- boids.addGroupObserver(this);
- }
-
- SteeringSystem::~SteeringSystem()
- {}
-
- void SteeringSystem::update(float t, float dt)
- {
- auto members = boids.getMembers();
-
- for (const SteeringGroup::Member* member: *members)
- {
- SteeringComponent* steering = std::get<0>(member->components);
-
- // Initialize summed steering force
- steering->force = Vector3(0.0f);
- steering->speed = 0.0f;
- float speedSquared = 0.0f;
- float maxSpeedSquared = steering->maxSpeed * steering->maxSpeed;
- bool truncated = false;
-
- if (steering->behaviorCount > 0)
- {
- // Sort steering beaviors by priority
- std::sort(steering->behaviors, steering->behaviors + steering->behaviorCount,
- [](const SteeringBehavior& a, const SteeringBehavior& b) -> bool
- {
- return (a.priority >= b.priority);
- }
- );
- }
-
- // Evaluate steering forces in order
- for (std::size_t i = 0; i < steering->behaviorCount; ++i)
- {
- const SteeringBehavior& behavior = steering->behaviors[i];
-
- // Skip zero-weighted steering behaviors
- if (behavior.weight == 0.0f)
- {
- continue;
- }
-
- // Add weighted steering behavior force
- steering->force += behavior.function() * behavior.weight;
-
- // Limit speed
- speedSquared = glm::length2(steering->force);
- if (speedSquared >= maxSpeedSquared)
- {
- steering->force *= (1.0f / std::sqrt(speedSquared)) * steering->maxSpeed;
- steering->speed = steering->maxSpeed;
- truncated = true;
- break;
- }
- }
-
- if (!truncated)
- {
- steering->speed = std::sqrt(speedSquared);
- }
- }
- }
-
- void SteeringSystem::memberRegistered(const SteeringGroup::Member* member)
- {}
-
- void SteeringSystem::memberUnregistered(const SteeringGroup::Member* member)
- {}
-
-
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