From a34fbcb0581056bd464158acfa30289a3e2c2c2d Mon Sep 17 00:00:00 2001
From: Daniel Karbach <daniel.karbach@localhorst.tv>
Date: Fri, 7 Aug 2015 16:49:24 +0200
Subject: [PATCH] check line of sight in chase ai

---
 src/ai/Chaser.hpp  |  8 ++++++--
 src/ai/Spawner.cpp |  2 +-
 src/ai/ai.cpp      | 36 +++++++++++++++++++++++++++---------
 3 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/src/ai/Chaser.hpp b/src/ai/Chaser.hpp
index 6daaf36..43667c0 100644
--- a/src/ai/Chaser.hpp
+++ b/src/ai/Chaser.hpp
@@ -6,11 +6,13 @@
 
 namespace blank {
 
+class World;
+
 class Chaser
 : public Controller {
 
 public:
-	Chaser(Entity &ctrl, Entity &tgt) noexcept;
+	Chaser(World &, Entity &ctrl, Entity &tgt) noexcept;
 	~Chaser();
 
 	Entity &Target() noexcept { return tgt; }
@@ -19,8 +21,10 @@ public:
 	void Update(int dt) override;
 
 private:
+	World &world;
 	Entity &tgt;
-	float speed;
+	float chase_speed;
+	float flee_speed;
 	float stop_dist;
 	float flee_dist;
 
diff --git a/src/ai/Spawner.cpp b/src/ai/Spawner.cpp
index c73bcde..612c3cc 100644
--- a/src/ai/Spawner.cpp
+++ b/src/ai/Spawner.cpp
@@ -111,7 +111,7 @@ void Spawner::Spawn(const glm::ivec3 &chunk, const glm::vec3 &pos) {
 	if (rand() % 2) {
 		ctrl = new RandomWalk(e);
 	} else {
-		ctrl = new Chaser(e, world.Player());
+		ctrl = new Chaser(world, e, world.Player());
 	}
 	controllers.emplace_back(ctrl);
 }
diff --git a/src/ai/ai.cpp b/src/ai/ai.cpp
index b3e1a0c..6b380e4 100644
--- a/src/ai/ai.cpp
+++ b/src/ai/ai.cpp
@@ -2,19 +2,23 @@
 #include "Controller.hpp"
 #include "RandomWalk.hpp"
 
+#include "../model/geometry.hpp"
 #include "../world/Entity.hpp"
+#include "../world/World.hpp"
 
 #include <glm/glm.hpp>
 
 
 namespace blank {
 
-Chaser::Chaser(Entity &ctrl, Entity &tgt) noexcept
+Chaser::Chaser(World &world, Entity &ctrl, Entity &tgt) noexcept
 : Controller(ctrl)
+, world(world)
 , tgt(tgt)
-, speed(0.002f)
-, stop_dist(5 * 5)
-, flee_dist(3 * 3) {
+, chase_speed(0.002f)
+, flee_speed(-0.005f)
+, stop_dist(10)
+, flee_dist(5) {
 
 }
 
@@ -24,12 +28,26 @@ Chaser::~Chaser() {
 
 void Chaser::Update(int dt) {
 	glm::vec3 diff(Target().AbsoluteDifference(Controlled()));
-	float dist = dot (diff, diff);
-	// TODO: line of sight test
-	if (dist > stop_dist) {
-		Controlled().Velocity(normalize(diff) * speed);
+	float dist = length(diff);
+	glm::vec3 norm_diff(diff / dist);
+
+	bool line_of_sight = true;
+	// FIXME: this only works if target is in the reference chunk (which is true for the player)
+	Ray aim{Target().Position() - diff, norm_diff};
+	Chunk *chunk;
+	int blkid;
+	float distance;
+	glm::vec3 normal;
+	if (world.Intersection(aim, glm::mat4(1.0f), chunk, blkid, distance, normal)) {
+		line_of_sight = distance > dist;
+	}
+
+	if (!line_of_sight) {
+		Controlled().Velocity(glm::vec3(0.0f));
+	} else if (dist > stop_dist) {
+		Controlled().Velocity(norm_diff * chase_speed);
 	} else if (dist < flee_dist) {
-		Controlled().Velocity(normalize(diff) * -speed);
+		Controlled().Velocity(norm_diff * flee_speed);
 	} else {
 		Controlled().Velocity(glm::vec3(0.0f));
 	}
-- 
2.39.2