From 431255dd13d40191001910d50ffafe2453242613 Mon Sep 17 00:00:00 2001
From: Stefano Pigozzi <me@steffo.eu>
Date: Sun, 3 Apr 2022 09:04:30 +0200
Subject: [PATCH] :boom: Properly setup bullet collisions

---
 project.godot                          |  5 +++--
 src/entities/Bullet.gd                 | 21 +++++++++++++++++++++
 src/entities/Bullet.tscn               | 10 +++++++---
 src/entities/Enemy.tscn                |  1 +
 src/entities/Player.tscn               |  1 +
 src/entities/behaviours/BulletSpawn.gd |  1 +
 src/entities/behaviours/Ownership.gd   |  6 +++---
 7 files changed, 37 insertions(+), 8 deletions(-)
 create mode 100644 src/entities/Bullet.gd

diff --git a/project.godot b/project.godot
index 44eb47d..f6fad7d 100644
--- a/project.godot
+++ b/project.godot
@@ -84,8 +84,9 @@ player_shoot={
 2d_render/layer_1="Game"
 2d_render/layer_2="UserInterface"
 2d_physics/layer_1="Entities"
-2d_physics/layer_2="Projectiles"
-2d_physics/layer_3="UI"
+2d_physics/layer_2="Damageable"
+2d_physics/layer_3="Projectiles"
+2d_physics/layer_4="UI"
 
 [physics]
 
diff --git a/src/entities/Bullet.gd b/src/entities/Bullet.gd
new file mode 100644
index 0000000..9e41186
--- /dev/null
+++ b/src/entities/Bullet.gd
@@ -0,0 +1,21 @@
+extends KinematicBody2D
+
+
+export var damage: int = 1
+
+
+func _on_BulletMovement_hit(collision: KinematicCollision2D):
+	# Find the owner of this bullet
+	var bullet_owner = Ownership.get_value(self)
+	# Check if the bullet should do damage		
+	var same_alliance = Alliance.compare(bullet_owner, collision.collider)
+	if same_alliance:
+		return
+	# Check if it is possible to damage the collider
+	var damageable = collision.collider.get_node("Damageable")
+	if damageable == null:
+		return
+	# Damage the collider!
+	damageable.health -= damage
+	# Alas, destroy self
+	queue_free()
diff --git a/src/entities/Bullet.tscn b/src/entities/Bullet.tscn
index d47abfa..c81ea27 100644
--- a/src/entities/Bullet.tscn
+++ b/src/entities/Bullet.tscn
@@ -1,18 +1,20 @@
-[gd_scene load_steps=5 format=2]
+[gd_scene load_steps=6 format=2]
 
 [ext_resource path="res://src/mechanics/White.png" type="Texture" id=1]
 [ext_resource path="res://src/entities/behaviours/BulletMovement.gd" type="Script" id=2]
 [ext_resource path="res://src/entities/behaviours/Ownership.tscn" type="PackedScene" id=3]
+[ext_resource path="res://src/entities/Bullet.gd" type="Script" id=4]
 
 [sub_resource type="RectangleShape2D" id=1]
 extents = Vector2( 16, 8 )
 
 [node name="Bullet" type="KinematicBody2D"]
-collision_layer = 2
+collision_layer = 4
+collision_mask = 2
+script = ExtResource( 4 )
 
 [node name="Shape" type="CollisionShape2D" parent="."]
 shape = SubResource( 1 )
-disabled = true
 
 [node name="Sprite" type="Sprite" parent="Shape"]
 scale = Vector2( 1, 0.5 )
@@ -22,3 +24,5 @@ texture = ExtResource( 1 )
 script = ExtResource( 2 )
 
 [node name="Ownership" parent="." instance=ExtResource( 3 )]
+
+[connection signal="hit" from="BulletMovement" to="." method="_on_BulletMovement_hit"]
diff --git a/src/entities/Enemy.tscn b/src/entities/Enemy.tscn
index 90874bc..434d2e7 100644
--- a/src/entities/Enemy.tscn
+++ b/src/entities/Enemy.tscn
@@ -10,6 +10,7 @@
 extents = Vector2( 16, 16 )
 
 [node name="Enemy" type="KinematicBody2D"]
+collision_layer = 3
 
 [node name="Shape" type="CollisionShape2D" parent="."]
 shape = SubResource( 1 )
diff --git a/src/entities/Player.tscn b/src/entities/Player.tscn
index 88161e9..1e21e58 100644
--- a/src/entities/Player.tscn
+++ b/src/entities/Player.tscn
@@ -10,6 +10,7 @@
 extents = Vector2( 16, 16 )
 
 [node name="Player" type="KinematicBody2D"]
+collision_layer = 3
 collision/safe_margin = 0.02
 
 [node name="Shape" type="CollisionShape2D" parent="."]
diff --git a/src/entities/behaviours/BulletSpawn.gd b/src/entities/behaviours/BulletSpawn.gd
index 02a7c9d..c41e4ad 100644
--- a/src/entities/behaviours/BulletSpawn.gd
+++ b/src/entities/behaviours/BulletSpawn.gd
@@ -19,3 +19,4 @@ func shoot():
 	var rotation = new_bullet.get_angle_to(source.get_global_mouse_position())
 	new_bullet.set_rotation(rotation)
 	new_bullet.get_node("Ownership").entity_owner = source
+	new_bullet.add_collision_exception_with(source)
diff --git a/src/entities/behaviours/Ownership.gd b/src/entities/behaviours/Ownership.gd
index bf77084..0286a91 100644
--- a/src/entities/behaviours/Ownership.gd
+++ b/src/entities/behaviours/Ownership.gd
@@ -7,7 +7,7 @@ var entity_owner: Node = null
 
 static func get_value(first) -> Node:
 	var first_node = first.get_node("Ownership")
-	var first_alliance = null
+	var first_eowner = null
 	if first_node != null:
-		first_alliance = first_node.alliance
-	return first_alliance
+		first_eowner = first_node.entity_owner
+	return first_eowner