ScriptableRenderPipeline/ScriptableRenderPipeline/Core/Debugging/Editor/DebugMenuEditor.cs

using UnityEditor;

namespace UnityEngine.Experimental.Rendering
{
    // This is the class that handles rendering the debug menu in the editor (as opposed to the runtime version in the player)
    public class DebugMenuEditor : EditorWindow
    {
        [SerializeField]
        private DebugMenuState m_DebugMenuState;

        [MenuItem("Edit/Render Pipeline/Tools/High Definition/Debug Window", priority = CoreUtils.editMenuPriority2)]
        static void DisplayDebugMenu()
        {
            var window = EditorWindow.GetWindow<DebugMenuEditor>("Debug Window");
            window.Show();
        }

        DebugMenuManager m_DebugMenu = null;

        void OnEnable()
        {
            m_DebugMenu = DebugMenuManager.instance;
            DebugItem.OnItemDirty += DebugItem_OnDirty;

            if(m_DebugMenuState == null)
            {
                m_DebugMenuState = ScriptableObject.CreateInstance<DebugMenuState>();
                m_DebugMenuState.hideFlags = HideFlags.DontSave;
            }
        }

        void OnDisable()
        {
            DebugItem.OnItemDirty -= DebugItem_OnDirty;
        }

        void OnDestroy()
        {
            Object.DestroyImmediate(m_DebugMenuState);
        }

        void DebugItem_OnDirty(DebugItem item)
        {
            DebugItemState debugItemState = m_DebugMenuState.FindDebugItemState(item);

            if(debugItemState != null)
            {
                UnityEditor.Undo.RecordObject(debugItemState, "DebugMenu State Update");
                debugItemState.SetValue(item.GetValue());
                EditorUtility.SetDirty(m_DebugMenuState);
            }
        }

        void OnGUI()
        {
            if (m_DebugMenu == null)
                return;

            // Contrary to the menu in the player, here we always render the menu wether it's enabled or not. This is a separate window so user can manage it however they want.
            EditorGUI.BeginChangeCheck();
            DebugMenuUI debugMenuUI = m_DebugMenu.menuUI;
            int debugMenuCount = m_DebugMenu.panelCount;
            int activePanelIndex = debugMenuUI.activePanelIndex;
            using (new EditorGUILayout.HorizontalScope())
            {
                for(int i = 0 ; i < debugMenuCount ; ++i)
                {
                    GUIStyle style = EditorStyles.miniButtonMid;
                    if (i == 0)
                        style = EditorStyles.miniButtonLeft;
                    if (i == debugMenuCount - 1)
                        style = EditorStyles.miniButtonRight;

                    string name = m_DebugMenu.GetDebugPanel(i).name;
                    if (GUILayout.Toggle(i == activePanelIndex, new GUIContent(name), style))
                        activePanelIndex = i;
                }
            }
            if(EditorGUI.EndChangeCheck())
            {
                debugMenuUI.activePanelIndex = activePanelIndex;
            }

            debugMenuUI.OnEditorGUI();
        }
    }

}