Add conditional showing of Clear Debug Draw buttons only if there is anything to clear

#2989

Source/Editor/Viewport/EditorViewport.cs

@@ -968,13 +968,12 @@ namespace FlaxEditor.Viewport
                     debugView.VisibleChanged += WidgetViewModeShowHide;
                 }
 
-                ViewWidgetButtonMenu.AddSeparator();
-
                 // Clear Debug Draw
                 {
                     var button = ViewWidgetButtonMenu.AddButton("Clear Debug Draw");
                     button.CloseMenuOnClick = false;
                     button.Clicked += () => DebugDraw.Clear();
+                    ViewWidgetButtonMenu.VisibleChanged += (Control cm) => { button.Visible = DebugDraw.CanClear(); };
                 }
 
                 ViewWidgetButtonMenu.AddSeparator();

Source/Editor/Windows/GameWindow.cs

@@ -117,7 +117,6 @@ namespace FlaxEditor.Windows
             {
                 if (!AudioMuted)
                     Audio.MasterVolume = value;
-
                 _audioVolume = value;
             }
         }
@@ -677,6 +676,14 @@ namespace FlaxEditor.Windows
                 checkbox.StateChanged += x => ShowDebugDraw = x.Checked;
             }
 
+            // Clear Debug Draw
+            if (DebugDraw.CanClear())
+            {
+                var button = menu.AddButton("Clear Debug Draw");
+                button.CloseMenuOnClick = false;
+                button.Clicked += () => DebugDraw.Clear();
+            }
+
             menu.AddSeparator();
 
             // Mute Audio
@@ -695,13 +702,6 @@ namespace FlaxEditor.Windows
                 slider.ValueChanged += () => AudioVolume = slider.Value;
             }
 
-            // Debug Draw Clear
-            {
-                var button = menu.AddButton("Clear Debug Draw");
-                button.CloseMenuOnClick = false;
-                button.Clicked += () => DebugDraw.Clear();
-            }
-
             menu.MinimumWidth = 200;
             menu.AddSeparator();
         }

Source/Engine/Debug/DebugDraw.cpp

@@ -347,6 +347,11 @@ struct DebugDrawContext
     DebugDrawData DebugDrawDepthTest;
     Float3 LastViewPos = Float3::Zero;
     Matrix LastViewProj = Matrix::Identity;
+
+    inline int32 Count() const
+    {
+        return DebugDrawDefault.Count() + DebugDrawDepthTest.Count();
+    }
 };
 
 namespace
@@ -739,6 +744,13 @@ void DebugDraw::SetContext(void* context)
     Context = context ? (DebugDrawContext*)context : &GlobalContext;
 }
 
+bool DebugDraw::CanClear(void* context)
+{
+    if (!context)
+        context = &GlobalContext;
+    return ((DebugDrawContext*)context)->Count() != 0;
+}
+
 #endif
 
 Vector3 DebugDraw::GetViewPos()

Source/Engine/Debug/DebugDraw.h

@@ -62,6 +62,13 @@ API_CLASS(Static) class FLAXENGINE_API DebugDraw
     /// </summary>
     /// <param name="context">The context or null.</param>
     API_FUNCTION() static void SetContext(void* context);
+
+    /// <summary>
+    /// Checks if can clear all debug shapes displayed on screen. Can be used to disable this functionality when not needed for the user.
+    /// </summary>
+    /// <param name="context">The context.</param>
+    /// <returns>True fi context can be cleared (has any shapes), otherwise false.</returns>
+    API_FUNCTION() static bool CanClear(void* context = nullptr);
 #endif
 
     // Gets the last view position when rendering the current context. Can be sued for custom culling or LODing when drawing more complex shapes.