From 1ffe1444b25811a1bf65461118ac454305a99b99 Mon Sep 17 00:00:00 2001
From: Colin McMillen <colin@semicolin.games>
Date: Sat, 15 Feb 2020 16:31:59 -0500
Subject: [PATCH] Debug: draw rects as 4 GPU-accelerated lines.

GitOrigin-RevId: 3286d0476b5032d785f74191609db4fbd768433c
---
 Shared/Debug.cs     | 41 +++++++++++------------------------------
 Shared/SneakGame.cs | 18 +++++-------------
 2 files changed, 16 insertions(+), 43 deletions(-)

diff --git a/Shared/Debug.cs b/Shared/Debug.cs
index df02aa8..b4cc752 100644
--- a/Shared/Debug.cs
+++ b/Shared/Debug.cs
@@ -27,20 +27,16 @@ namespace SemiColinGames {
     }
 
     public static bool Enabled = true;
-    // Lines in excess of MAX_LINES get dropped on the floor.
-    const int MAX_LINES = 1000;
-    const int MAX_LINE_VERTICES = MAX_LINES * 2;
     // This is a LinkedList instead of a List because SetFpsText() adds to its front.
     static readonly LinkedList<string> toasts = new LinkedList<string>();
-    static readonly List<DebugRect> rects = new List<DebugRect>();
+    // Lines in excess of MAX_LINES get dropped on the floor.
+    const int MAX_LINES = 2000;
+    const int MAX_LINE_VERTICES = MAX_LINES * 2;
     static int lineIdx = 0;
     static readonly VertexPositionColor[] lineVertices = new VertexPositionColor[MAX_LINE_VERTICES];
     static VertexBuffer vertexBuffer;
 
-    static Texture2D whiteTexture;
-
-    public static void Initialize(GraphicsDevice graphics, Texture2D white) {
-      whiteTexture = white;
+    public static void Initialize(GraphicsDevice graphics) {
       vertexBuffer = new VertexBuffer(
           graphics, typeof(VertexPositionColor), MAX_LINE_VERTICES, BufferUsage.WriteOnly);
     }
@@ -56,7 +52,6 @@ namespace SemiColinGames {
     public static void Clear(bool paused) {
       toasts.Clear();
       if (!paused) {
-        rects.Clear();
         lineIdx = 0;
       }
     }
@@ -71,7 +66,10 @@ namespace SemiColinGames {
     }
 
     public static void AddRect(Rectangle rect, Color color) {
-      rects.Add(new DebugRect(rect, color));
+      AddLine(rect.Left, rect.Top, rect.Right, rect.Top, color);
+      AddLine(rect.Right, rect.Top, rect.Right, rect.Bottom, color);
+      AddLine(rect.Right, rect.Bottom, rect.Left, rect.Bottom, color);
+      AddLine(rect.Left, rect.Bottom, rect.Left, rect.Top, color);
     }
 
     public static void AddRect(AABB box, Color color) {
@@ -109,31 +107,14 @@ namespace SemiColinGames {
       }
     }
 
-    public static void Draw(
-        SpriteBatch spriteBatch, GraphicsDevice graphics, BasicEffect lightingEffect) {
+    public static void Draw(GraphicsDevice graphics, BasicEffect lightingEffect) {
       if (!Enabled) {
         return;
       }
-
-      // Draw rects.
-      foreach (var debugRect in rects) {
-        var rect = debugRect.Rect;
-        var color = debugRect.Color;
-        // top side
-        spriteBatch.Draw(
-          whiteTexture, new Rectangle(rect.Left, rect.Top, rect.Width, 1), color);
-        // bottom side
-        spriteBatch.Draw(
-          whiteTexture, new Rectangle(rect.Left, rect.Bottom - 1, rect.Width, 1), color);
-        // left side
-        spriteBatch.Draw(
-          whiteTexture, new Rectangle(rect.Left, rect.Top, 1, rect.Height), color);
-        // right side
-        spriteBatch.Draw(
-          whiteTexture, new Rectangle(rect.Right - 1, rect.Top, 1, rect.Height), color);
+      if (lineIdx == 0) {
+        return;
       }
 
-      // Draw lines.
       graphics.SetVertexBuffer(vertexBuffer);
       vertexBuffer.SetData(lineVertices);
       foreach (EffectPass pass in lightingEffect.CurrentTechnique.Passes) {
diff --git a/Shared/SneakGame.cs b/Shared/SneakGame.cs
index ca648ef..1414097 100644
--- a/Shared/SneakGame.cs
+++ b/Shared/SneakGame.cs
@@ -33,7 +33,6 @@ namespace SemiColinGames {
     int framesToSuppress = 2;
     Texture2D grasslandBg1;
     Texture2D grasslandBg2;
-    Texture2D whiteTexture;
 
     Player player;
     World world;
@@ -57,6 +56,8 @@ namespace SemiColinGames {
       display.Initialize(Window, graphics);
       display.SetFullScreen(fullScreen);
 
+      Debug.Initialize(GraphicsDevice);
+
       sceneTarget = new RenderTarget2D(
         GraphicsDevice, camera.Width, camera.Height, false /* mipmap */,
         GraphicsDevice.PresentationParameters.BackBufferFormat, DepthFormat.Depth24);
@@ -79,6 +80,7 @@ namespace SemiColinGames {
 
     // Called once per game. Loads all game content.
     protected override void LoadContent() {
+      base.LoadContent();
       spriteBatch = new SpriteBatch(GraphicsDevice);
       font = Content.Load<SpriteFont>("font");
 
@@ -87,20 +89,13 @@ namespace SemiColinGames {
       linesOfSight = new LinesOfSight(GraphicsDevice);
       grasslandBg1 = Content.Load<Texture2D>("grassland_bg1");
       grasslandBg2 = Content.Load<Texture2D>("grassland_bg2");
-
-      whiteTexture = new Texture2D(GraphicsDevice, 1, 1);
-      whiteTexture.SetData(new Color[] { Color.White });
-      Debug.Initialize(GraphicsDevice, whiteTexture);
     }
 
     // Called once per game. Unloads all game content.
     protected override void UnloadContent() {
-      whiteTexture.Dispose();
-
+      base.UnloadContent();
       updateTimer.DumpStats();
       drawTimer.DumpStats();
-
-      base.UnloadContent();
     }
 
     // Updates the game world.
@@ -193,10 +188,7 @@ namespace SemiColinGames {
       linesOfSight.Draw(player, world.CollisionTargets, GraphicsDevice, lightingEffect);
 
       // Draw debug rects & lines on top.
-      spriteBatch.Begin(
-          SpriteSortMode.Deferred, null, SamplerState.LinearWrap, null, null, null, transform);
-      Debug.Draw(spriteBatch, GraphicsDevice, lightingEffect);
-      spriteBatch.End();
+      Debug.Draw(GraphicsDevice, lightingEffect);
 
       // Draw sceneTarget to screen.
       GraphicsDevice.SetRenderTarget(null);