From d8b82c4feea986c36ac240ec25272ee975252dff Mon Sep 17 00:00:00 2001
From: Matt Low <mattjlow94@gmail.com>
Date: Sat, 25 Jan 2020 13:18:38 +0400
Subject: [PATCH] Fix screen wrapping math

Rather than place entities directly on the screen edge boundary, add the
distance they were beyond the screen edge.

Store aabb in ModelComponent for use by multiple systems.
---
 .../com/me/asteroids/components/ModelComponent.java  |  3 ++-
 .../src/com/me/asteroids/systems/MovementSystem.java |  1 +
 .../com/me/asteroids/systems/ScreenWrapSystem.java   | 12 +++++-------
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/core/src/com/me/asteroids/components/ModelComponent.java b/core/src/com/me/asteroids/components/ModelComponent.java
index 57e4c69..f7408dd 100644
--- a/core/src/com/me/asteroids/components/ModelComponent.java
+++ b/core/src/com/me/asteroids/components/ModelComponent.java
@@ -1,10 +1,11 @@
 package com.me.asteroids.components;
 
 import com.badlogic.gdx.math.Polygon;
+import com.badlogic.gdx.math.Rectangle;
 import com.me.common.ecs.Component;
 
 public class ModelComponent extends Component {
 
     public Polygon model;
-
+    public Rectangle aabb;
 }
diff --git a/core/src/com/me/asteroids/systems/MovementSystem.java b/core/src/com/me/asteroids/systems/MovementSystem.java
index 75b5fb9..7c344bf 100644
--- a/core/src/com/me/asteroids/systems/MovementSystem.java
+++ b/core/src/com/me/asteroids/systems/MovementSystem.java
@@ -41,6 +41,7 @@ public class MovementSystem extends EntitySystem {
             Polygon model = modelComponent.model;
             model.setPosition(position.x, position.y);
             model.setRotation(positionComponent.rotation - 90);
+            modelComponent.aabb = model.getBoundingRectangle();
         }
     }
 
diff --git a/core/src/com/me/asteroids/systems/ScreenWrapSystem.java b/core/src/com/me/asteroids/systems/ScreenWrapSystem.java
index 345438a..4c519e5 100644
--- a/core/src/com/me/asteroids/systems/ScreenWrapSystem.java
+++ b/core/src/com/me/asteroids/systems/ScreenWrapSystem.java
@@ -1,6 +1,5 @@
 package com.me.asteroids.systems;
 
-import com.badlogic.gdx.math.Polygon;
 import com.badlogic.gdx.math.Rectangle;
 import com.badlogic.gdx.math.Vector2;
 import com.me.asteroids.Constants;
@@ -21,17 +20,16 @@ public class ScreenWrapSystem extends EntitySystem {
         ModelComponent modelComponent = entity.getComponent(ModelComponent.class);
 
         Vector2 position = positionComponent.position;
-        Polygon model = modelComponent.model;
-        Rectangle aabb = model.getBoundingRectangle();
+        Rectangle aabb = modelComponent.aabb;
 
         // Check top/bottom edges
         float minY = aabb.y;
         float maxY = minY + aabb.height;
         if (minY > Constants.HEIGHT) {
-            position.y = position.y - maxY;
+            position.y = (position.y - maxY) + (minY - Constants.HEIGHT);
             return;
         } else if (maxY < 0) {
-            position.y = Constants.HEIGHT + (position.y - minY);
+            position.y = Constants.HEIGHT + (position.y - minY) + maxY;
             return;
         }
 
@@ -39,9 +37,9 @@ public class ScreenWrapSystem extends EntitySystem {
         float minX = aabb.x;
         float maxX = minX + aabb.width;
         if (maxX < 0) {
-            position.x = Constants.WIDTH + (position.x - minX);
+            position.x = Constants.WIDTH + (position.x - minX) + maxX;
         }  else if (minX > Constants.WIDTH) {
-            position.x = position.x - maxX;
+            position.x = (position.x - maxX) + (minX - Constants.WIDTH);
 
         }
     }