1 files changed, 75 insertions, 0 deletions
diff --git a/src/crepe/system/AISystem.cpp b/src/crepe/system/AISystem.cpp
new file mode 100644
index 0000000..9029f32
--- /dev/null
+++ b/src/crepe/system/AISystem.cpp
@@ -0,0 +1,75 @@
+#include "../ComponentManager.h"
+#include "api/LoopTimer.h"
+#include "api/Transform.h"
+#include "types.h"
+
+#include "AISystem.h"
+
+using namespace crepe;
+
+void AISystem::update() {
+	ComponentManager & mgr = this->component_manager;
+	RefVector<AI> ai_components = mgr.get_components_by_type<AI>();
+
+	double dt = LoopTimer::get_instance().get_delta_time();
+
+	for (AI & ai : ai_components) {
+		vec2 force = this->calculate(ai);
+		vec2 acceleration = force / ai.mass;
+		ai.velocity += acceleration * dt;
+		ai.velocity.truncate(ai.max_speed);
+
+		// Update the position
+		RefVector<Transform> transforms
+			= mgr.get_components_by_id<Transform>(ai.game_object_id);
+		Transform & transform = transforms.front().get();
+		transform.position += ai.velocity * dt;
+	}
+}
+
+vec2 AISystem::calculate(AI & ai) {
+	vec2 force;
+
+	if (ai.on(AI::BehaviorType::SEEK)) {
+		vec2 force_to_add = this->seek(ai);
+
+		if (!this->accumulate_force(force, force_to_add)) {
+			return force;
+		}
+	}
+	if (ai.on(AI::BehaviorType::FLEE)) {
+		// Flee from the target
+	}
+	if (ai.on(AI::BehaviorType::ARRIVE)) {
+		// Arrive at the target
+	}
+	if (ai.on(AI::BehaviorType::PATH_FOLLOW)) {
+		// Follow the path
+	}
+
+	return force;
+}
+
+bool AISystem::accumulate_force(vec2 & running_total, vec2 force_to_add) {
+	double magnitude_remaining = running_total.length();
+	double magnitude_to_add = force_to_add.length();
+
+	if (magnitude_remaining + magnitude_to_add > 0) {
+		running_total += force_to_add;
+		return true;
+	}
+
+	return false;
+}
+
+vec2 AISystem::seek(const AI & ai) {
+	ComponentManager & mgr = this->component_manager;
+	RefVector<Transform> transforms = mgr.get_components_by_id<Transform>(ai.game_object_id);
+	Transform & transform = transforms.front().get();
+
+	vec2 desired_velocity = ai.seek_target - transform.position;
+	desired_velocity.normalize();
+	desired_velocity *= ai.max_speed;
+
+	return desired_velocity - ai.velocity;
+}