From d9c9008cf4af454ebfe51232ac53aa30865056b6 Mon Sep 17 00:00:00 2001
From: Evan Hemsley <2342303+ehemsley@users.noreply.github.com>
Date: Wed, 12 Jun 2019 11:16:10 -0700
Subject: [PATCH] engine decorator references

---
 content/pong/ball/bouncing/spawners.md | 6 ------
 content/pong/ball/moving.md            | 7 +++----
 content/pong/ball/spawning.md          | 7 +++----
 content/pong/scoring/drawing_score.md  | 2 +-
 4 files changed, 7 insertions(+), 15 deletions(-)

diff --git a/content/pong/ball/bouncing/spawners.md b/content/pong/ball/bouncing/spawners.md
index 9c76c6f..66570c4 100644
--- a/content/pong/ball/bouncing/spawners.md
+++ b/content/pong/ball/bouncing/spawners.md
@@ -40,8 +40,6 @@ import { World } from "lua-lib/bump";
 
 @Reads(BallSpawnMessage)
 export class BallSpawner extends Spawner {
-    public spawn_message_type = BallSpawnMessage;
-
     public collision_world: World;
 
     public initialize(collision_world: World) {
@@ -110,8 +108,6 @@ import { World } from "lua-lib/bump";
 
 @Reads(GameBoundarySpawnMessage)
 export class GameBoundarySpawner extends Spawner {
-    public spawn_message_type = GameBoundarySpawnMessage;
-
     private collision_world: World;
 
     public initialize(collision_world: World) {
@@ -174,8 +170,6 @@ import { World } from "lua-lib/bump";
 
 @Reads(PaddleSpawnMessage)
 export class PaddleSpawner extends Spawner {
-    public spawn_message_type = PaddleSpawnMessage;
-
     private collision_world: World;
 
     public initialize(collision_world: World) {
diff --git a/content/pong/ball/moving.md b/content/pong/ball/moving.md
index 116f795..44abda0 100644
--- a/content/pong/ball/moving.md
+++ b/content/pong/ball/moving.md
@@ -36,9 +36,8 @@ import { VelocityComponent } from "game/components/velocity";
 import { MotionMessage } from "game/messages/component/motion";
 
 @Emits(MotionMessage)
+@Detects(PositionComponent, VelocityComponent)
 export class VelocityEngine extends Detector {
-    public component_types = [ PositionComponent, VelocityComponent ];
-
     protected detect(entity: Entity) {
         const position_component = entity.get_component(PositionComponent);
         const velocity_component = entity.get_component(VelocityComponent);
@@ -50,9 +49,9 @@ export class VelocityEngine extends Detector {
 }
 ```
 
-A Detector, like a Spawner, is an engine with one required property and method: *component_types* and *detect*.
+A Detector, like a Spawner, is an engine with one required method: *detect*.
 
-When an Entity has all of the components specified in *component_types*, it begins to track the Entity. Each frame, it calls its *detect* method on that Entity.
+When an Entity has all of the components specified in **@Detects**, it begins to track the Entity. Each frame, it calls its *detect* method on that Entity.
 
 So, our VelocityEngine will track everything with a PositionComponent and VelocityComponent and create a MotionMessage every frame.
 
diff --git a/content/pong/ball/spawning.md b/content/pong/ball/spawning.md
index 0fc83bc..eb14da2 100644
--- a/content/pong/ball/spawning.md
+++ b/content/pong/ball/spawning.md
@@ -41,8 +41,6 @@ import { BallSpawnMessage } from "game/messages/ball_spawn";
 
 @Reads(BallSpawnMessage)
 export class BallSpawner extends Spawner {
-    public spawn_message_type = BallSpawnMessage;
-
     public spawn(message: BallSpawnMessage) {
         const ball_entity = this.create_entity();
 
@@ -65,9 +63,10 @@ export class BallSpawner extends Spawner {
 }
 ```
 
-Spawners aren't very complicated. They have one required property and method: *spawn_message_type* and *spawn*.
+Spawners aren't very complicated. They have one required method: *spawn*.
+The first Message type given to **@Reads** is assumed to be the spawn message type.
 
-When the Spawner reads a message of *spawn_message_type*, it runs its spawn method once. Simple as that.
+When the Spawner reads a message of the spawn message type, it runs its spawn method once. Simple as that.
 
 Now let's actually send out the BallSpawnMessage.
 
diff --git a/content/pong/scoring/drawing_score.md b/content/pong/scoring/drawing_score.md
index b78aa2b..4295139 100644
--- a/content/pong/scoring/drawing_score.md
+++ b/content/pong/scoring/drawing_score.md
@@ -77,7 +77,7 @@ It's also very expensive to create a new LOVE Font every frame. Like the Text ob
 Let's add our ScoreRenderer to the WorldBuilder.
 
 ```ts
-world_builder.add_renderer(ScoreRenderer);
+world_builder.add_renderer(ScoreRenderer).initialize(play_area_width * 0.5);
 ```
 
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