From 478c042f335e7d590797acf3dcb028d8a278ecc7 Mon Sep 17 00:00:00 2001
From: jvbsl <jvsbl@gmx.de>
Date: Sun, 12 Mar 2023 18:23:08 +0100
Subject: [PATCH] Restore VertexBuffer/IndexBuffer/EffectPass after
 SpriteBatch.End

---
 Graphics/Effect/EffectPass.cs | 10 +++++++++-
 Graphics/IndexBuffer.cs       | 35 +++++++++++++++++++++++++++++++++++
 Graphics/SpriteBatcher.cs     | 26 ++++++++++++++------------
 Graphics/VertexBuffer.cs      | 35 +++++++++++++++++++++++++++++++++++
 4 files changed, 93 insertions(+), 13 deletions(-)

diff --git a/Graphics/Effect/EffectPass.cs b/Graphics/Effect/EffectPass.cs
index 6433bc3..8d71c0a 100644
--- a/Graphics/Effect/EffectPass.cs
+++ b/Graphics/Effect/EffectPass.cs
@@ -20,6 +20,14 @@ public class EffectPass : GraphicsResource, IDisposable
             private readonly GraphicsDevice _graphicsDevice;
             private readonly EffectPass? _oldValue;
 
+            /// <summary>
+            /// Restores the active <see cref="GraphicsDevice.EffectPass"/> to the given value on dispose.
+            /// </summary>
+            /// <param name="graphicsDevice">The <see cref="GraphicsDevice"/> to restore on.</param>
+            public PassRestorer(GraphicsDevice graphicsDevice) : this(graphicsDevice, graphicsDevice.EffectPass)
+            {
+            }
+
             /// <summary>
             /// Restores the active <see cref="GraphicsDevice.EffectPass"/> to the given value on dispose.
             /// </summary>
@@ -215,7 +223,7 @@ internal void Link()
         public PassRestorer Apply()
         {
             GraphicsDevice.ValidateUiGraphicsThread();
-            var passRestorer = new PassRestorer(GraphicsDevice, GraphicsDevice.EffectPass);
+            var passRestorer = new PassRestorer(GraphicsDevice);
             GraphicsDevice.EffectPass = this;
 
             return passRestorer;
diff --git a/Graphics/IndexBuffer.cs b/Graphics/IndexBuffer.cs
index e1f34a8..2056c3a 100644
--- a/Graphics/IndexBuffer.cs
+++ b/Graphics/IndexBuffer.cs
@@ -10,6 +10,41 @@ namespace engenious.Graphics
     /// </summary>
     public class IndexBuffer : GraphicsResource
     {
+        /// <summary>
+        /// Class that restores the active <see cref="GraphicsDevice.IndexBuffer"/> on dispose.
+        /// </summary>
+        public readonly struct IndexBufferRestorer : IDisposable
+        {
+            private readonly GraphicsDevice _graphicsDevice;
+            private readonly IndexBuffer? _oldValue;
+
+            /// <summary>
+            /// Restores the active <see cref="GraphicsDevice.IndexBuffer"/> to the given value on dispose.
+            /// </summary>
+            /// <param name="graphicsDevice">The <see cref="GraphicsDevice"/> to restore on.</param>
+            public IndexBufferRestorer(GraphicsDevice graphicsDevice) : this(graphicsDevice,
+                graphicsDevice.IndexBuffer)
+            {
+
+            }
+
+            /// <summary>
+            /// Restores the active <see cref="GraphicsDevice.IndexBuffer"/> to the given value on dispose.
+            /// </summary>
+            /// <param name="graphicsDevice">The <see cref="GraphicsDevice"/> to restore on.</param>
+            /// <param name="oldValue">The <see cref="IndexBuffer"/> to restore to.</param>
+            public IndexBufferRestorer(GraphicsDevice graphicsDevice, IndexBuffer? oldValue)
+            {
+                _graphicsDevice = graphicsDevice;
+                _oldValue = oldValue;
+            }
+
+            /// <inheritdoc />
+            public void Dispose()
+            {
+                _graphicsDevice.IndexBuffer = _oldValue;
+            }
+        }
         private int _ibo;
         //private byte[] buffer;
         private readonly int _elementSize;
diff --git a/Graphics/SpriteBatcher.cs b/Graphics/SpriteBatcher.cs
index c52091b..9844bb3 100644
--- a/Graphics/SpriteBatcher.cs
+++ b/Graphics/SpriteBatcher.cs
@@ -191,20 +191,22 @@ public void Flush(IModelTechnique effectTechnique, Texture texture, int batch, i
             _indexBuffer.SetData(sizeof(short) * 6 * batch, _indexData, 0, batchCount * 6);
 
 
-            _graphicsDevice.VertexBuffer = _vertexBuffer;
-            _graphicsDevice.IndexBuffer = _indexBuffer;
-            effectTechnique.Texture = texture;
-            //graphicsDevice.SamplerStates[0] = samplerState;
-            if (effectTechnique == null)
-                throw new Exception("No valid effect technique set");
-            foreach (var pass in effectTechnique.Passes)
+            using (new VertexBuffer.VertexBufferRestorer(_graphicsDevice))
+            using (new IndexBuffer.IndexBufferRestorer(_graphicsDevice))
+            using (new EffectPass.PassRestorer(_graphicsDevice))
             {
-                pass.Apply();
-                _graphicsDevice.DrawIndexedPrimitives(PrimitiveType.Triangles, 0, 0, batchCount * 4, 0, batchCount * 2);
+                _graphicsDevice.VertexBuffer = _vertexBuffer;
+                _graphicsDevice.IndexBuffer = _indexBuffer;
+                effectTechnique.Texture = texture;
+                //graphicsDevice.SamplerStates[0] = samplerState;
+                if (effectTechnique == null)
+                    throw new Exception("No valid effect technique set");
+                foreach (var pass in effectTechnique.Passes)
+                {
+                    pass.Apply();
+                    _graphicsDevice.DrawIndexedPrimitives(PrimitiveType.Triangles, 0, 0, batchCount * 4, 0, batchCount * 2);
+                }
             }
-
-            _graphicsDevice.IndexBuffer = null;
-            _graphicsDevice.VertexBuffer = null;
         }
 
         public void End(Matrix world, Matrix projection)
diff --git a/Graphics/VertexBuffer.cs b/Graphics/VertexBuffer.cs
index 19cab07..a779ad4 100644
--- a/Graphics/VertexBuffer.cs
+++ b/Graphics/VertexBuffer.cs
@@ -12,6 +12,41 @@ namespace engenious.Graphics
     /// </summary>
     public class VertexBuffer : GraphicsResource
     {
+        /// <summary>
+        /// Class that restores the active <see cref="GraphicsDevice.VertexBuffer"/> on dispose.
+        /// </summary>
+        public readonly struct VertexBufferRestorer : IDisposable
+        {
+            private readonly GraphicsDevice _graphicsDevice;
+            private readonly VertexBuffer? _oldValue;
+
+            /// <summary>
+            /// Restores the active <see cref="GraphicsDevice.VertexBuffer"/> to the given value on dispose.
+            /// </summary>
+            /// <param name="graphicsDevice">The <see cref="GraphicsDevice"/> to restore on.</param>
+            public VertexBufferRestorer(GraphicsDevice graphicsDevice) : this(graphicsDevice,
+                graphicsDevice.VertexBuffer)
+            {
+
+            }
+
+            /// <summary>
+            /// Restores the active <see cref="GraphicsDevice.VertexBuffer"/> to the given value on dispose.
+            /// </summary>
+            /// <param name="graphicsDevice">The <see cref="GraphicsDevice"/> to restore on.</param>
+            /// <param name="oldValue">The <see cref="VertexBuffer"/> to restore to.</param>
+            public VertexBufferRestorer(GraphicsDevice graphicsDevice, VertexBuffer? oldValue)
+            {
+                _graphicsDevice = graphicsDevice;
+                _oldValue = oldValue;
+            }
+
+            /// <inheritdoc />
+            public void Dispose()
+            {
+                _graphicsDevice.VertexBuffer = _oldValue;
+            }
+        }
         internal int Vbo, NextVbo = -1;
         internal long NextVertexCount;
         internal VertexAttributes? Vao;