Two small fixes (#904)

* Fix index check in CSelectSlide.RenameValue

The check used && instead of ||. An index cannot be negative and out
of range at the same time, so the check never returned early and an
invalid index caused an ArgumentOutOfRangeException.

* Allow textures to be disposed more than once

CTextureBase.Dispose threw ObjectDisposedException on a second call.
Dispose must be safe to call multiple times, otherwise freeing a
texture twice crashes the game.

Return early instead. CD3DTexture and COGLTexture also check
IsDisposed first, so a second call does not free the GPU texture
again. This matters for OpenGL, where the texture name may already
belong to another texture.

---------

Co-authored-by: Florian Ostertag <flokuep@users.noreply.github.com>

Vocaluxe/Lib/Draw/CDirect3D.cs

@@ -65,6 +65,11 @@ namespace Vocaluxe.Lib.Draw
 
         public override void Dispose()
         {
+            if (IsDisposed)
+            {
+                return;
+            }
+
             base.Dispose();
             if (D3DTexture != null)
             {

Vocaluxe/Lib/Draw/COpenGL.cs

@@ -91,6 +91,11 @@ namespace Vocaluxe.Lib.Draw
 
         public override void Dispose()
         {
+            if (IsDisposed)
+            {
+                return;
+            }
+
             base.Dispose();
             if (Name != 0)
             {

Vocaluxe/Lib/Draw/CTextureBase.cs

@@ -92,17 +92,17 @@ namespace Vocaluxe.Lib.Draw
             }
         }
 
-        private bool _IsDisposed;
+        protected bool IsDisposed { get; private set; }
 
         public virtual void Dispose()
         {
-            if (_IsDisposed)
+            if (IsDisposed)
             {
-                throw new ObjectDisposedException(GetType().Name);
+                return;
             }
 
             RefCount = 0;
-            _IsDisposed = true;
+            IsDisposed = true;
         }
     }
 }

VocaluxeLib/Menu/CSelectSlide.cs

@@ -389,7 +389,7 @@ namespace VocaluxeLib.Menu
 
         public void RenameValue(int index, string newName, CTextureRef newTexture = null)
         {
-            if (index < 0 && index >= _Values.Count)
+            if (index < 0 || index >= _Values.Count)
             {
                 return;
             }