center line

PongFE/PongFEGame.cs

@@ -32,8 +32,8 @@ namespace PongFE
         public PongFEGame()
         {
             graphics = new GraphicsDeviceManager(this);
-            graphics.PreferredBackBufferWidth = 1680;
+            graphics.PreferredBackBufferWidth = 1920;
-            graphics.PreferredBackBufferHeight = 1050;
+            graphics.PreferredBackBufferHeight = 1080;
             graphics.PreferMultiSampling = true;
             Content.RootDirectory = "Content";
 
@@ -81,6 +81,7 @@ namespace PongFE
             WorldBuilder.AddEngine(new PaddleSpawner(WhitePixel));
 
             WorldBuilder.AddOrderedRenderer(new Texture2DRenderer(SpriteBatch));
+            WorldBuilder.AddGeneralRenderer(new CenterLineRenderer(SpriteBatch, WhitePixel), 0);
             WorldBuilder.AddGeneralRenderer(new ScoreRenderer(SpriteBatch, ScoreFont), 0);
 
             WorldBuilder.SendMessage(

PongFE/Renderers/CenterLineRenderer.cs

@@ -0,0 +1,65 @@
+using System;
+using Encompass;
+using Microsoft.Xna.Framework;
+using Microsoft.Xna.Framework.Graphics;
+using PongFE.Components;
+
+namespace PongFE.Renderers
+{
+    public class CenterLineRenderer : GeneralRenderer
+    {
+        public SpriteBatch SpriteBatch { get; }
+        public Texture2D WhitePixel { get; }
+
+        public CenterLineRenderer(SpriteBatch spriteBatch, Texture2D whitePixel)
+        {
+            SpriteBatch = spriteBatch;
+            WhitePixel = whitePixel;
+        }
+
+        public override void Render()
+        {
+            ref readonly var playAreaComponent = ref ReadComponent<PlayAreaComponent>();
+
+            DrawDottedLine(playAreaComponent.Width / 2, 0, playAreaComponent.Width / 2, playAreaComponent.Height, 20, 20);
+        }
+
+        private void DrawDottedLine(float x1, float y1, float x2, float y2, int dash, int gap)
+        {
+            var dx = x2 - x1;
+            var dy = y2 - y1;
+            var angle = Math.Atan2(dy, dx);
+            var st = dash + gap;
+            var len = Math.Sqrt(dx * dx + dy * dy);
+            var nm = (len - dash) / st;
+
+            SpriteBatch.End();
+            SpriteBatch.Begin(
+                SpriteSortMode.Deferred,
+                null,
+                null,
+                null,
+                null,
+                null,
+                Matrix.CreateRotationZ((float)angle) * Matrix.CreateTranslation(x1, y1, 0)
+            );
+
+            for (var i = 0; i < nm; i++)
+            {
+                SpriteBatch.Draw(
+                    WhitePixel,
+                    new Rectangle(
+                        (int)(i * st + gap * 0.5),
+                        0,
+                        dash,
+                        1
+                    ),
+                    Color.White
+                );
+            }
+
+            SpriteBatch.End();
+            SpriteBatch.Begin(SpriteSortMode.Deferred, BlendState.NonPremultiplied);
+        }
+    }
+}