Add TemporarySpriteBatch

Celeste.Mod.mm/Celeste.Mod.mm.csproj

@@ -5,7 +5,6 @@
     <AssemblyName>Celeste.Mod.mm</AssemblyName>
     <RootNamespace>Celeste</RootNamespace>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-    <LangVersion>11</LangVersion>
     <ShouldIncludeNativeLua>false</ShouldIncludeNativeLua>
   </PropertyGroup>
 

Celeste.Mod.mm/Mod/Helpers/TemporarySpriteBatch.cs

@@ -0,0 +1,244 @@
+#nullable enable
+
+using Microsoft.Xna.Framework;
+using Microsoft.Xna.Framework.Graphics;
+using Monocle;
+using MonoMod.Utils;
+using System.Buffers;
+
+namespace Celeste.Mod.Helpers;
+
+/// <summary>
+///   A temporary <see cref="SpriteBatch"/>.
+/// </summary>
+/// <remarks>
+///   When constructed, the current <see cref="SpriteBatch"/> properties and <see cref="RenderTarget2D"/> are preserved.
+///   Then, the <see cref="SpriteBatch"/> is ended, the <see cref="RenderTarget2D"/> is swapped if necessary,
+///   and finally the <see cref="SpriteBatch"/> is restarted with the new properties.<br/>
+///   When disposed, the previous <see cref="SpriteBatch"/> properties and <see cref="RenderTarget2D"/> are restored.
+///   <br/>
+///   Useful when interrupting a <see cref="SpriteBatch"/> mid-render to, for example, render a specific entity to a
+///   temporary <see cref="RenderTarget2D"/> while applying a custom shader, all while preserving the previous
+///   configuration.<br/>
+///   <b>Note: Restarting a spritebatch flushes it to the GPU.</b>
+///   While the cost is not that significant, it's best to avoid restarting the spritebatch too often per frame.
+/// </remarks>
+/// <seealso cref="TemporarySpriteBatchBuilder"/>
+public ref struct TemporarySpriteBatch
+{
+    // we don't really expect the RenderTargetBinding[] array size to exceed 1,
+    // so a max of 16 seems reasonable
+    private static readonly ArrayPool<RenderTargetBinding> _renderTargetPool
+        = ArrayPool<RenderTargetBinding>.Create(0x10, 50);
+
+    /// <summary>
+    ///   The <see cref="SpriteSortMode"/> of this <see cref="TemporarySpriteBatch"/>.
+    /// </summary>
+    public readonly SpriteSortMode CurrentSortMode;
+
+    /// <summary>
+    ///   The <see cref="BlendState"/> of this <see cref="TemporarySpriteBatch"/>.
+    /// </summary>
+    public readonly BlendState CurrentBlendState;
+
+    /// <summary>
+    ///   The <see cref="SamplerState"/> of this <see cref="TemporarySpriteBatch"/>.
+    /// </summary>
+    public readonly SamplerState CurrentSamplerState;
+
+    /// <summary>
+    ///   The <see cref="DepthStencilState"/> of this <see cref="TemporarySpriteBatch"/>.
+    /// </summary>
+    public readonly DepthStencilState CurrentDepthStencilState;
+
+    /// <summary>
+    ///   The <see cref="RasterizerState"/> of this <see cref="TemporarySpriteBatch"/>.
+    /// </summary>
+    public readonly RasterizerState CurrentRasterizerState;
+
+    /// <summary>
+    ///   The custom <see cref="Effect"/> of this <see cref="TemporarySpriteBatch"/>.
+    /// </summary>
+    public readonly Effect? CurrentCustomEffect;
+
+    /// <summary>
+    ///   The transformation <see cref="Matrix"/> of this <see cref="TemporarySpriteBatch"/>.
+    /// </summary>
+    public readonly Matrix CurrentTransformMatrix;
+
+    /// <summary>
+    ///   The <see cref="RenderTarget2D"/> swapped in for the duration of this <see cref="TemporarySpriteBatch"/>
+    ///   or <c>null</c> to draw to the screen if <see cref="HasRenderTarget"/> is <c>true</c>; else always <c>null</c>.
+    /// </summary>
+    public readonly RenderTarget2D? CurrentRenderTarget;
+
+
+    /// <summary>
+    ///   The <see cref="SpriteSortMode"/> that was used prior to the start of this
+    ///   <see cref="TemporarySpriteBatch"/>.
+    /// </summary>
+    public readonly SpriteSortMode PreviousSortMode;
+
+    /// <summary>
+    ///   The <see cref="BlendState"/> that was used prior to the start of this
+    ///   <see cref="TemporarySpriteBatch"/>.
+    /// </summary>
+    public readonly BlendState PreviousBlendState;
+
+    /// <summary>
+    ///   The <see cref="SamplerState"/> that was used prior to the start of this
+    ///   <see cref="TemporarySpriteBatch"/>.
+    /// </summary>
+    public readonly SamplerState PreviousSamplerState;
+
+    /// <summary>
+    ///   The <see cref="DepthStencilState"/> that was used prior to the start of this
+    ///   <see cref="TemporarySpriteBatch"/>.
+    /// </summary>
+    public readonly DepthStencilState PreviousDepthStencilState;
+
+    /// <summary>
+    ///   The <see cref="RasterizerState"/> that was used prior to the start of this
+    ///   <see cref="TemporarySpriteBatch"/>.
+    /// </summary>
+    public readonly RasterizerState PreviousRasterizerState;
+
+    /// <summary>
+    ///   The custom <see cref="Effect"/> that was used prior to the start of this
+    ///   <see cref="TemporarySpriteBatch"/>.
+    /// </summary>
+    public readonly Effect? PreviousCustomEffect;
+
+    /// <summary>
+    ///   The transformation <see cref="Matrix"/> that was used prior to the start of this
+    ///   <see cref="TemporarySpriteBatch"/>.
+    /// </summary>
+    public readonly Matrix PreviousTransformMatrix;
+
+    /// <summary>
+    ///   The <see cref="RenderTargetBinding"/>s that were used prior to the start of this <see cref="TemporarySpriteBatch"/>
+    ///   or <c>null</c> to draw to the screen if <see cref="HasRenderTarget"/> is <c>true</c>; else always <c>null</c>.
+    /// </summary>
+    public readonly RenderTargetBinding[]? PreviousRenderTargets;
+
+
+    /// <summary>
+    ///   Whether a <see cref="RenderTarget2D"/> was swapped in for the duration of this
+    ///   <see cref="TemporarySpriteBatch"/>.
+    /// </summary>
+    public readonly bool HasRenderTarget;
+
+    /// <summary>
+    ///   Whether this <see cref="TemporarySpriteBatch"/> is still active.
+    /// </summary>
+    public bool Active { get; private set; }
+
+
+    /// <summary>
+    ///   Create and immediately begin a new <see cref="TemporarySpriteBatch"/>.
+    /// </summary>
+    /// <seealso cref="TemporarySpriteBatchBuilder"/>
+    internal TemporarySpriteBatch(
+        SpriteSortMode? sortMode,
+        BlendState? blendState,
+        SamplerState? samplerState,
+        DepthStencilState? depthStencilState,
+        RasterizerState? rasterizerState,
+        Effect? customEffect,
+        Matrix? transformMatrix,
+        RenderTarget2D? renderTarget,
+        bool hasCustomEffect,
+        bool hasRenderTarget)
+    {
+        GetSpriteBatchFields(
+            out PreviousSortMode,
+            out PreviousBlendState,
+            out PreviousSamplerState,
+            out PreviousDepthStencilState,
+            out PreviousRasterizerState,
+            out PreviousCustomEffect,
+            out PreviousTransformMatrix);
+
+        CurrentSortMode = sortMode ?? PreviousSortMode;
+        CurrentBlendState = blendState ?? PreviousBlendState;
+        CurrentSamplerState = samplerState ?? PreviousSamplerState;
+        CurrentDepthStencilState = depthStencilState ?? PreviousDepthStencilState;
+        CurrentRasterizerState = rasterizerState ?? PreviousRasterizerState;
+        CurrentCustomEffect = hasCustomEffect ? customEffect : PreviousCustomEffect;
+        CurrentTransformMatrix = transformMatrix ?? PreviousTransformMatrix;
+
+        HasRenderTarget = hasRenderTarget;
+
+        GraphicsDevice graphicsDevice = Engine.Graphics.GraphicsDevice;
+        if (hasRenderTarget)
+        {
+            int renderTargetCount = graphicsDevice.GetRenderTargetsNoAllocEXT(null);
+            if (renderTargetCount > 0)
+            {
+                PreviousRenderTargets = _renderTargetPool.Rent(renderTargetCount);
+                graphicsDevice.GetRenderTargetsNoAllocEXT(PreviousRenderTargets);
+            }
+            CurrentRenderTarget = renderTarget;
+        }
+
+        Active = true;
+        Draw.SpriteBatch.End();
+        if (hasRenderTarget)
+            Engine.Graphics.GraphicsDevice.SetRenderTarget(CurrentRenderTarget);
+        Draw.SpriteBatch.Begin(
+            CurrentSortMode,
+            CurrentBlendState,
+            CurrentSamplerState,
+            CurrentDepthStencilState,
+            CurrentRasterizerState,
+            CurrentCustomEffect,
+            CurrentTransformMatrix);
+    }
+
+    /// <summary>
+    ///   End this <see cref="TemporarySpriteBatch"/>, restore the previous render targets if necessary, and restore
+    ///   the previous <see cref="SpriteBatch"/> properties.
+    /// </summary>
+    public void Dispose()
+    {
+        if (!Active)
+            return;
+
+        Active = false;
+        Draw.SpriteBatch.End();
+        if (HasRenderTarget)
+        {
+            Engine.Graphics.GraphicsDevice.SetRenderTargets(PreviousRenderTargets);
+            _renderTargetPool.Return(PreviousRenderTargets!, clearArray: true);
+        }
+        Draw.SpriteBatch.Begin(
+            PreviousSortMode,
+            PreviousBlendState,
+            PreviousSamplerState,
+            PreviousDepthStencilState,
+            PreviousRasterizerState,
+            PreviousCustomEffect,
+            PreviousTransformMatrix);
+    }
+
+    private static void GetSpriteBatchFields(
+        out SpriteSortMode sortMode,
+        out BlendState blendState,
+        out SamplerState samplerState,
+        out DepthStencilState depthStencilState,
+        out RasterizerState rasterizerState,
+        out Effect? customEffect,
+        out Matrix transformMatrix)
+    {
+        // life would be good if we could just access these directly...
+
+        DynamicData dynData = DynamicData.For(Draw.SpriteBatch);
+        sortMode = dynData.Get<SpriteSortMode>("sortMode");
+        blendState = dynData.Get<BlendState>("blendState")!;
+        samplerState = dynData.Get<SamplerState>("samplerState")!;
+        depthStencilState = dynData.Get<DepthStencilState>("depthStencilState")!;
+        rasterizerState = dynData.Get<RasterizerState>("rasterizerState")!;
+        customEffect = dynData.Get<Effect>("customEffect");
+        transformMatrix = dynData.Get<Matrix>("transformMatrix");
+    }
+}