AI done

Assets/Prefabs/Ball.prefab

@@ -102,6 +102,7 @@ MonoBehaviour:
   m_Script: {fileID: 11500000, guid: 267dfd77302043669cc125190ddfb575, type: 3}
   m_Name: 
   m_EditorClassIdentifier: 
+  rb: {fileID: 0}
 --- !u!114 &8059693774009316043
 MonoBehaviour:
   m_ObjectHideFlags: 0
@@ -179,7 +180,7 @@ Rigidbody2D:
   m_Material: {fileID: 0}
   m_Interpolate: 0
   m_SleepingMode: 1
-  m_CollisionDetection: 0
+  m_CollisionDetection: 1
   m_Constraints: 0
 --- !u!114 &8029731608843643848
 MonoBehaviour:

Assets/Scenes/Game.unity

@@ -169,10 +169,10 @@ EdgeCollider2D:
   m_UsedByEffector: 0
   m_UsedByComposite: 0
   m_Offset: {x: 0, y: 0}
-  m_EdgeRadius: 0
+  m_EdgeRadius: 0.33
   m_Points:
-  - {x: -10, y: -15}
   - {x: -10, y: 15}
+  - {x: -10, y: -15}
   m_AdjacentStartPoint: {x: 0, y: 0}
   m_AdjacentEndPoint: {x: 0, y: 0}
   m_UseAdjacentStartPoint: 0
@@ -320,7 +320,7 @@ SpriteRenderer:
   m_SortingLayer: 0
   m_SortingOrder: -1
   m_Sprite: {fileID: 7482667652216324306, guid: 311925a002f4447b3a28927169b83ea6, type: 3}
-  m_Color: {r: 0.22628158, g: 0.28601155, b: 0.4245283, a: 1}
+  m_Color: {r: 0.20705765, g: 0.2779592, b: 0.4433962, a: 1}
   m_FlipX: 0
   m_FlipY: 0
   m_DrawMode: 0
@@ -339,7 +339,7 @@ Transform:
   m_GameObject: {fileID: 338338487}
   m_LocalRotation: {x: 0, y: 0, z: 0, w: 1}
   m_LocalPosition: {x: 0, y: 0, z: 0}
-  m_LocalScale: {x: 20, y: 30, z: 1}
+  m_LocalScale: {x: 20, y: 30, z: 0}
   m_ConstrainProportionsScale: 0
   m_Children: []
   m_Father: {fileID: 0}
@@ -446,8 +446,8 @@ EdgeCollider2D:
   m_Offset: {x: 0, y: 0}
   m_EdgeRadius: 0
   m_Points:
-  - {x: -10, y: 15}
-  - {x: 10, y: 15}
+  - {x: -10, y: -15}
+  - {x: 10, y: -15}
   m_AdjacentStartPoint: {x: 0, y: 0}
   m_AdjacentEndPoint: {x: 0, y: 0}
   m_UseAdjacentStartPoint: 0
@@ -500,8 +500,8 @@ EdgeCollider2D:
   m_Offset: {x: 0, y: 0}
   m_EdgeRadius: 0
   m_Points:
-  - {x: 10, y: -15}
   - {x: 10, y: 15}
+  - {x: 10, y: -15}
   m_AdjacentStartPoint: {x: 0, y: 0}
   m_AdjacentEndPoint: {x: 0, y: 0}
   m_UseAdjacentStartPoint: 0
@@ -711,8 +711,8 @@ EdgeCollider2D:
   m_Offset: {x: 0, y: 0}
   m_EdgeRadius: 0
   m_Points:
-  - {x: -10, y: -15}
-  - {x: 10, y: -15}
+  - {x: -10, y: 15}
+  - {x: 10, y: 15}
   m_AdjacentStartPoint: {x: 0, y: 0}
   m_AdjacentEndPoint: {x: 0, y: 0}
   m_UseAdjacentStartPoint: 0

Assets/Scripts/BorderSize.cs

@@ -11,6 +11,8 @@ public class BorderSize : MonoBehaviour {
 
 	public static BorderSize Singleton;
 
+	public Vector2 Size => new(x2 - x1, y2 - y1);
+
 	private void OnEnable() {
 		Singleton = this;
 		top = transform.Find("Top").GetComponent<EdgeCollider2D>();
@@ -20,16 +22,16 @@ public class BorderSize : MonoBehaviour {
 	}
 	
 	private void Update() {
-		Vector2 v1 = new Vector2(x1, y1);
-		Vector2 v2 = new Vector2(x2, y1);
-		Vector2 v3 = new Vector2(x1, y2);
-		Vector2 v4 = new Vector2(x2, y2);
+		Vector2 v1 = new Vector2(x1, y2);
+		Vector2 v2 = new Vector2(x2, y2);
+		Vector2 v3 = new Vector2(x1, y1);
+		Vector2 v4 = new Vector2(x2, y1);
 		top.points = new[] {v1, v2};
 		bottom.points = new[] {v3, v4};
 		left.points = new[] {v1, v3};
 		right.points = new[] {v2, v4};
 
-		playGround.localPosition = new Vector3((x2 + x1) / 2, (y2 + y1) / 2, 0);
-		playGround.localScale = new Vector3(x2 - x1, y2 - y1, 1);
+		playGround.localPosition = new Vector3((x1 + x2) / 2, (y1 + y2) / 2, 0);
+		playGround.localScale = Size;
 	}
 }

Assets/Scripts/Game/Ball.cs

@@ -1,8 +1,28 @@
+using System;
 using Unity.Netcode;
 using UnityEngine;
 
 namespace Game {
 	public class Ball : NetworkBehaviour {
+		public Rigidbody2D rb;
 
+		public float Radius => transform.localScale.x / 4;
+
+		public bool IsAlive {
+			get {
+				float y = transform.position.y;
+				float y1 = BorderSize.Singleton.y1;
+				float y2 = BorderSize.Singleton.y2;
+				return y > y1 && y < y2;
+			}
+		}
+
+		private void OnEnable() {
+			rb = GetComponent<Rigidbody2D>();
+		}
+
+		private void Start() {
+			rb.velocity = new Vector2(0, 20);
+		}
 	}
 }

Assets/Scripts/Game/GameManager.cs

@@ -1,25 +1,68 @@
 using System;
+using System.Collections;
+using System.Collections.Generic;
 using Unity.Netcode;
 using Unity.VisualScripting;
 using UnityEngine;
+using UnityEngine.Assertions;
 using Object = UnityEngine.Object;
 
 namespace Game {
 	public class GameManager : NetworkBehaviour {
 
+		public static GameManager Singleton { get; private set; }
+
+		private void OnEnable() {
+			Singleton = this;
+		}
+
 		public Object ballPrefab;
 		public Object playerPrefab;
 
+		public List<Ball> Balls { get; } = new();
+
+		private static void Tests() {
+			var v1 = new Vector2(1, 3);
+			var v2 = new Vector2(3, 2);
+			var v3 = new Vector2(4, 4);
+			var v4 = new Vector2(1, 1);
+			var v5 = new Vector2(4, 1);
+			var v6 = new Vector2(2, 5);
+			var v7 = new Vector2(2, 3);
+			var v8 = new Vector2(-1, 4);
+			var v9 = new Vector2(-2, 1);
+			var v10 = new Vector2(3, -1);
+			Assert.IsTrue(AIPlayer.Intersect(v8, v4, v1, v9, out _));
+			Assert.IsTrue(AIPlayer.Intersect(v1, v2, v4, v7, out _));
+			Assert.IsTrue(AIPlayer.Intersect(v10, v6, v9, v2, out _));
+			Assert.IsTrue(AIPlayer.Intersect(v9, v5, v8, v10, out _));
+			Assert.IsFalse(AIPlayer.Intersect(v8, v4, v6, v5, out _));
+			Assert.IsFalse(AIPlayer.Intersect(v3, v5, v6, v8, out _));
+			Assert.IsFalse(AIPlayer.Intersect(v10, v4, v8, v9, out _));
+			Assert.IsFalse(AIPlayer.Intersect(v1, v7, v3, v2, out _));
+
+			var v11 = new Vector2(0, 4.8f);
+			var v12 = new Vector2(0, 14.8f);
+			var v13 = new Vector2(-9.75f, 14.75f);
+			var v14 = new Vector2(9.75f, 14.75f);
+			Assert.IsTrue(AIPlayer.Intersect(v11, v12, v13, v14, out _));
+		}
+
 		private void Start() {
 			//var ball = Instantiate(ballPrefab, Vector2.zero, Quaternion.identity).GetComponent<Ball>();
-			var ball = FindObjectOfType(typeof(Ball));
-			var rb = ball.GetComponent<Rigidbody2D>();
-			rb.velocity = new Vector2(0, 10);
-
-			var p1 = Instantiate(playerPrefab, new Vector2(0, BorderSize.Singleton.y1), Quaternion.identity);
-			var p2 = Instantiate(playerPrefab, new Vector2(0, BorderSize.Singleton.y2), Quaternion.identity);
-			p1.AddComponent<AIPlayer>();
-			p2.AddComponent<RealPlayer>();
+			var ball = FindObjectOfType(typeof(Ball)).GetComponent<Ball>();
+			Balls.Add(ball);
+
+			var p1Obj = Instantiate(playerPrefab);
+			var p2Obj = Instantiate(playerPrefab);
+			var p1 = p1Obj.AddComponent<AIPlayer>();
+			var p2 = p2Obj.AddComponent<RealPlayer>();
+			p1.Side = Player.ESide.Top;
+			p2.Side = Player.ESide.Bottom;
+			p1.Difficulty = AIPlayer.EDifficulty.VeryEasy;
+			p2.isThisClient = true;
+
+			Tests();
 		}
 
 	}

Assets/Scripts/Game/Player.cs

@@ -1,34 +1,33 @@
 using System;
+using System.Collections;
 using Unity.Netcode;
 using UnityEngine;
 using UnityEngine.InputSystem;
 using UnityEngine.PlayerLoop;
 using Random = UnityEngine.Random;
+using System.Linq;
+using UnityEngine.Serialization;
 
 namespace Game {
 	public class Player : NetworkBehaviour {
 		
+		public enum ESide {Top, Bottom}
+
+		public ESide Side { get; set; }
+
 		private int score;
 		
-		protected bool GoingLeft, GoingRight;
+		protected bool goingLeft, goingRight;
 
 		// Units per second
-		private float baseSpeed = 10;
+		protected float Speed => 10;
 		
 		// Unit distance from zero
-		private float baseBorder = 7;
+		private float Border => 10;
 		
 		private SpeedModification speedModification;
 		private BorderModification borderModification;
 
-		private float GetSpeed() {
-			return baseSpeed;
-		}
-
-		private float GetBorder() {
-			return baseBorder;
-		}
-		
 		private float LeftSide() {
 			return X() - transform.localScale.x / 2;
 		}
@@ -41,45 +40,167 @@ namespace Game {
 			return transform.position.x;
 		}
 
+		protected float Y() {
+			return transform.position.y;
+		}
+
 		protected void TryMove(float h) {
-			Vector2 trans = new Vector2((GoingLeft ? -1 : 0) + (GoingRight ? 1 : 0), 0);
-			trans *= baseSpeed * h;
+			Vector2 trans = new Vector2((goingLeft ? -1 : 0) + (goingRight ? 1 : 0), 0);
+			trans *= Speed * h;
 			transform.Translate(trans);
-			Debug.Log(trans.magnitude);
-			if (LeftSide() < -baseBorder)
-				transform.Translate(Vector2.right * (-baseBorder - LeftSide()));
-			if (RightSide() > baseBorder) 
-				transform.Translate(Vector2.left * (RightSide() - baseBorder));
+			if (LeftSide() < -Border)
+				transform.Translate(Vector2.right * (-Border - LeftSide()));
+			if (RightSide() > Border) 
+				transform.Translate(Vector2.left * (RightSide() - Border));
+		}
+
+		private void Start() {
+			float y = Side switch {
+				ESide.Bottom => BorderSize.Singleton.y1,
+				ESide.Top => BorderSize.Singleton.y2,
+				_ => throw new ArgumentOutOfRangeException()
+			};
+			transform.position = new Vector2(0, y);
 		}
 	}
 
 	public class AIPlayer : Player {
-		public enum Difficulty {
+		public enum EDifficulty {
 			VeryEasy, Easy, Medium, Hard, VeryHard
 		}
 
-		private Difficulty difficulty = Difficulty.VeryEasy;
+		public EDifficulty Difficulty { get; set; }
+
+		// True if ball y velocity points towards player
+		private bool BallApproaches(Ball ball) {
+			var ballVy = ball.rb.velocity.y;
+			return Side switch {
+				ESide.Bottom => ballVy < 0,
+				ESide.Top => ballVy > 0,
+				_ => throw new Exception("Side not set on player!")
+			};
+		}
+
+		// Not manhattan, only Y direction
+		private float YDistanceToBall(Ball ball) {
+			return Mathf.Abs(ball.rb.position.y - Y());
+		}
+
+		// o: Origin, e: End
+		public static bool Intersect(Vector2 o1, Vector2 e1, Vector2 o2, Vector2 e2, out Vector2 point) {
+			point = Vector2.zero;
+			
+			Vector2 m1 = e1 - o1;
+			Vector2 m2 = e2 - o2;
+
+			/*
+			 * o1x + r * m1x = o2x + s * m2x
+			 * o1y + r * m1y = o2y + s * m2y
+			 *
+			 * Solve for r and s:
+			 * Formulas below achieved by reordering
+			 * Order is irrelevant, but if m1x == 0 then first approach results in division by zero ->
+			 * Invert order then, and if division by zero is still a problem, both lines are parallel anyway
+			 */
+			
+			float r, s;
+			if (m1.x != 0) {
+				s = (o1.y + o2.x * m1.y / m1.x - o1.x * m1.y / m1.x - o2.y) / (m2.y - m2.x * m1.y / m1.x);
+				r = (o2.x + s * m2.x - o1.x) / m1.x;
+			} else if (m2.x != 0) {
+				r = (o2.y + o1.x * m2.y / m2.x - o2.x * m2.y / m2.x - o1.y) / (m1.y - m1.x * m2.y / m2.x);
+				s = (o1.x + r * m1.x - o2.x) / m2.x;
+			} else {
+				return false;
+			}
+
+			if (s is > 0 and < 1 && r is > 0 and < 1) {
+				point = o1 + r * m1;
+				return true;
+			}
+			
+			return false;
+		}
+
+		private Vector2 Simulate(Vector2 origin, Vector2 velocity, float radius, float secondsLeft) {
+			Vector2 validAreaOrigin = new Vector2(BorderSize.Singleton.x1, BorderSize.Singleton.y1) + new Vector2(radius, radius);
+			Vector2 validAreaSize = BorderSize.Singleton.Size - new Vector2(radius, radius) * 2;
+			Rect area = new Rect(validAreaOrigin, validAreaSize);
+
+			Vector2 end = origin + velocity * secondsLeft;
+			if (area.Contains(end))
+				return end;
+
+			float playerY = Side == ESide.Bottom ? area.yMin : area.yMax;
+			Vector2 playerLeft = new Vector2(area.xMin, playerY);
+			Vector2 playerRight = new Vector2(area.xMax, playerY);
+
+			// Horizontal line (player line) -> stop simulating
+			if (Intersect(origin, end, playerLeft, playerRight, out Vector2 point))
+				return point;
+
+			bool borderHit = false;
+			Vector2 borderHitPoint = Vector2.zero;
+
+			// Left vertical border
+			if (Intersect(origin, end, new Vector2(area.xMin, area.yMin), new Vector2(area.xMin, area.yMax), out point)) {
+				borderHit = true;
+				borderHitPoint = point;
+			}
+
+			// Right vertical border
+			if (Intersect(origin, end, new Vector2(area.xMax, area.yMin), new Vector2(area.xMax, area.yMax), out point)) {
+				borderHit = true;
+				borderHitPoint = point;
+			}
+
+			// Any border -> invert x velocity and simulate all seconds left
+			if (borderHit) {
+				secondsLeft -= (borderHitPoint - origin).magnitude / Speed;
+				velocity = new Vector2(-velocity.x, velocity.y);
+				origin = borderHitPoint;
+				return Simulate(origin, velocity, radius, secondsLeft);
+			}
+
+			// No intersection -> Ball outside of field -> dont simulate further
+			return origin;
+		}
+
+		private float FutureSeconds => (float)Difficulty * 0.5f;
 
 		private float GetTargetPosition() {
+			var balls = GameManager.Singleton.Balls.Where(b => b.IsAlive);
+			var approaching = balls.Where(BallApproaches).ToList();
 			
+			if (approaching.Count == 0)
+				return X();
 
-			return 0;
+			Ball ball = approaching.Aggregate(approaching[0], (prev, current) => YDistanceToBall(current) < YDistanceToBall(prev) ? current : prev);
+			Vector2 origin = ball.rb.position;
+			Vector2 velocity = ball.rb.velocity;
+			float radius = ball.Radius;
+			return Simulate(origin, velocity, radius, FutureSeconds).x;
 		}
 
 		private void FixedUpdate() {
 			float target = GetTargetPosition();
-			const float h = 1;
-			GoingLeft = target < X() - h;
-			GoingRight = target > X() + h;
+			const float h = 0.5f;
+			goingLeft = target < X() - h;
+			goingRight = target > X() + h;
 			TryMove(Time.fixedDeltaTime);
 		}
 	}
 
 	public class RealPlayer : Player {
+		public bool isThisClient;
+		
 		private void FixedUpdate() {
+			if (!isThisClient)
+				return;
+			
 			var keyboard = Keyboard.current;
-			GoingLeft = keyboard.aKey.isPressed;
-			GoingRight = keyboard.dKey.isPressed;
+			goingLeft = keyboard.aKey.isPressed;
+			goingRight = keyboard.dKey.isPressed;
 
 			TryMove(Time.fixedDeltaTime);
 		}

Pong.sln.DotSettings

@@ -1,4 +1,5 @@
 <wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/Abbreviations/=UXML/@EntryIndexedValue">UXML</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/PredefinedNamingRules/=PrivateInstanceFields/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="aaBb" /&gt;</s:String>
-	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/PredefinedNamingRules/=PrivateStaticFields/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="aaBb" /&gt;</s:String></wpf:ResourceDictionary>
+	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/PredefinedNamingRules/=PrivateStaticFields/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="aaBb" /&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/PredefinedNamingRules/=PublicFields/@EntryIndexedValue">&lt;Policy Inspect="False" Prefix="" Suffix="" Style="AaBb" /&gt;</s:String></wpf:ResourceDictionary>

packages.config

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<packages>
+  <package id="NUnit" version="3.13.3" targetFramework="net471" />
+</packages>