From 121387ba92a23d6f17b36331d25757abc899f7d2 Mon Sep 17 00:00:00 2001
From: max-001 <maxsmits21@kpnmail.nl>
Date: Wed, 4 Dec 2024 17:27:51 +0100
Subject: Implemeted seek behavior

---
 src/crepe/api/AI.h            |  3 +++
 src/crepe/system/AISystem.cpp | 45 +++++++++++++++++++++++++++++++++++++++++--
 src/crepe/system/AISystem.h   |  3 +++
 src/example/AITest.cpp        |  4 ++--
 4 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/src/crepe/api/AI.h b/src/crepe/api/AI.h
index faeeba5..242ff89 100644
--- a/src/crepe/api/AI.h
+++ b/src/crepe/api/AI.h
@@ -51,6 +51,9 @@ public:
 	float arrive_deceleration = 2.0f;
 
 private:
+	vec2 velocity;
+	friend class AISystem;
+
 	int flags = 0;
 };
 
diff --git a/src/crepe/system/AISystem.cpp b/src/crepe/system/AISystem.cpp
index 12da3d9..9029f32 100644
--- a/src/crepe/system/AISystem.cpp
+++ b/src/crepe/system/AISystem.cpp
@@ -1,4 +1,7 @@
 #include "../ComponentManager.h"
+#include "api/LoopTimer.h"
+#include "api/Transform.h"
+#include "types.h"
 
 #include "AISystem.h"
 
@@ -8,9 +11,19 @@ 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;
 	}
 }
 
@@ -18,7 +31,11 @@ vec2 AISystem::calculate(AI & ai) {
 	vec2 force;
 
 	if (ai.on(AI::BehaviorType::SEEK)) {
-		// Seek the target
+		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
@@ -32,3 +49,27 @@ vec2 AISystem::calculate(AI & ai) {
 
 	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;
+}
diff --git a/src/crepe/system/AISystem.h b/src/crepe/system/AISystem.h
index eb8d08c..5e94ccb 100644
--- a/src/crepe/system/AISystem.h
+++ b/src/crepe/system/AISystem.h
@@ -15,6 +15,9 @@ public:
 
 private:
 	vec2 calculate(AI & ai);
+	bool accumulate_force(vec2 & running_total, vec2 force_to_add);
+
+	vec2 seek(const AI & ai);
 };
 
 } // namespace crepe
diff --git a/src/example/AITest.cpp b/src/example/AITest.cpp
index 1c4633f..341e1de 100644
--- a/src/example/AITest.cpp
+++ b/src/example/AITest.cpp
@@ -18,13 +18,13 @@ public:
 	void load_scene() override {
 		ComponentManager & mgr = this->component_manager;
 
-		GameObject game_object1 = mgr.new_object("", "", vec2{0, 0}, 0, 1);
+		GameObject game_object1 = mgr.new_object("", "", vec2{250, 250}, 0, 1);
 		GameObject game_object2 = mgr.new_object("", "", vec2{0, 0}, 0, 1);
 
 		Texture img = Texture("asset/texture/test_ap43.png");
 		game_object1.add_component<Sprite>(img, Color::MAGENTA,
 										   Sprite::FlipSettings{false, false}, 1, 1, 195);
-		game_object1.add_component<AI>(1, 1, 1);
+		game_object1.add_component<AI>(1, 200, 200).seek_on();
 
 		game_object2.add_component<Camera>(Color::WHITE, ivec2{1080, 720}, vec2{1036, 780},
 										   1.0f);
-- 
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