Textures: allowed backend to destroy texture while inside the NewFrame/EndFrame scope. (#8811)

imgui.h

@@ -3491,8 +3491,10 @@ struct ImTextureData
     ImTextureID         GetTexID() const            { return TexID; }
 
     // Called by Renderer backend
-    void                SetTexID(ImTextureID tex_id)      { TexID = tex_id; }   // Call after creating or destroying the texture. Never modify TexID directly!
-    void                SetStatus(ImTextureStatus status) { Status = status; }  // Call after honoring a request. Never modify Status directly!
+    // - Call SetTexID() and SetStatus() after honoring texture requests. Never modify TexID and Status directly!
+    // - A backend may decide to destroy a texture that we did not request to destroy, which is fine (e.g. freeing resources), but we immediately set the texture back in _WantCreate mode.
+    void    SetTexID(ImTextureID tex_id)            { TexID = tex_id; }
+    void    SetStatus(ImTextureStatus status)       { Status = status; if (status == ImTextureStatus_Destroyed && !WantDestroyNextFrame) Status = ImTextureStatus_WantCreate; }
 };
 
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