should save shaders into shared data instead because frame buffer is …

…highly related to shader.

it might cause not found issue if changing frame buffer dictionary and drawing at the same time.

osu.Framework.Font/Graphics/MultiShaderBufferedDrawNode.cs

@@ -20,8 +20,6 @@ public class MultiShaderBufferedDrawNode : BufferedDrawNode
 
         protected new MultiShaderBufferedDrawNodeSharedData SharedData => (MultiShaderBufferedDrawNodeSharedData)base.SharedData;
 
-        private IShader[] shaders = { };
-
         private readonly double loadTime;
 
         public MultiShaderBufferedDrawNode(IBufferedDrawable source, DrawNode child, MultiShaderBufferedDrawNodeSharedData sharedData)
@@ -33,19 +31,13 @@ public MultiShaderBufferedDrawNode(IBufferedDrawable source, DrawNode child, Mul
         public override void ApplyState()
         {
             base.ApplyState();
-
-            if (shaders.SequenceEqual(Source.Shaders))
-                return;
-
-            // should clear buffer if property changed because might be shader amount changed.
-            shaders = Source.Shaders.ToArray();
-            SharedData.CreateDefaultFrameBuffers(shaders);
+            SharedData.UpdateFrameBuffers(Source.Shaders.ToArray());
         }
 
         protected override long GetDrawVersion()
         {
             // if contains shader that need to apply time, then need to force run populate contents in each frame.
-            if (ContainTimePropertyShader(shaders))
+            if (ContainTimePropertyShader(SharedData.Shaders))
             {
                 ResetDrawVersion();
             }
@@ -91,10 +83,6 @@ protected override void DrawContents()
             {
                 foreach (var frameBuffer in drawFrameBuffers)
                 {
-                    // got no idea why happened.
-                    if (frameBuffer.Texture == null)
-                        break;
-
                     DrawFrameBuffer(frameBuffer, DrawRectangle, Color4.White);
                 }
             }
@@ -107,6 +95,7 @@ protected override void DrawContents()
 
         private void drawFrameBuffer()
         {
+            var shaders = SharedData.Shaders;
             if (!shaders.Any())
                 return;
 

osu.Framework.Font/Graphics/MultiShaderBufferedDrawNodeSharedData.cs

@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.IO;
 using System.Linq;
 using System.Reflection;
 using osu.Framework.Graphics.OpenGL;
@@ -17,6 +16,8 @@ public class MultiShaderBufferedDrawNodeSharedData : BufferedDrawNodeSharedData
     {
         private readonly Dictionary<IShader, FrameBuffer> shaderBuffers = new Dictionary<IShader, FrameBuffer>();
 
+        public IShader[] Shaders => shaderBuffers.Keys.ToArray();
+
         private readonly RenderbufferInternalFormat[] formats;
 
         public MultiShaderBufferedDrawNodeSharedData(RenderbufferInternalFormat[] formats = null, bool pixelSnapping = false)
@@ -25,11 +26,12 @@ public MultiShaderBufferedDrawNodeSharedData(RenderbufferInternalFormat[] format
             this.formats = formats;
         }
 
-        public void CreateDefaultFrameBuffers(IShader[] shaders)
+        public void UpdateFrameBuffers(IShader[] shaders)
         {
             if (shaderBuffers.Keys.SequenceEqual(shaders))
                 return;
 
+            // collect all frame buffer that needs to be disposed.
             var disposedFrameBuffer = shaderBuffers.Values.ToArray();
             shaderBuffers.Clear();
 
@@ -66,15 +68,15 @@ public FrameBuffer GetSourceFrameBuffer(IShader shader)
                 return CurrentEffectBuffer;
 
             if (!shaderBuffers.ContainsKey(fromShader))
-                throw new DirectoryNotFoundException();
+                throw new KeyNotFoundException();
 
             return shaderBuffers[fromShader];
         }
 
         public FrameBuffer GetTargetFrameBuffer(IShader shader)
         {
             if (!shaderBuffers.ContainsKey(shader))
-                throw new DirectoryNotFoundException();
+                throw new KeyNotFoundException();
 
             return shaderBuffers[shader];
         }
@@ -90,7 +92,12 @@ public void UpdateBuffer(IShader shader, FrameBuffer frameBuffer)
         public FrameBuffer[] GetDrawFrameBuffers()
             => shaderBuffers.Where(x =>
             {
-                var shader = x.Key;
+                var (shader, frameBuffer) = x;
+
+                // should not render disposed or not created frame buffer.
+                if (frameBuffer.Texture == null)
+                    return false;
+
                 if (shader is IStepShader stepShader)
                     return stepShader.StepShaders.Any() && stepShader.Draw;