Adds state and parameter selectors.

AnimatorProperties.cs

//=============================================================================
// Licensed under CC0. Takanori Shibasaki
//=============================================================================
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using UnityEngine;

[System.Serializable]
public struct AnimatorStateName
{
    [SerializeField]
    internal int m_Hash;

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static implicit operator int(AnimatorStateName name)
    {
        return name.m_Hash;
    }

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static implicit operator bool(AnimatorStateName name)
    {
        return name.m_Hash != 0;
    }
}

[System.Serializable]
public struct AnimatorParameterName
{
    [SerializeField]
    internal int m_Hash;

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static implicit operator int(AnimatorParameterName name)
    {
        return name.m_Hash;
    }

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static implicit operator bool(AnimatorParameterName name)
    {
        return name.m_Hash != 0;
    }
}

#if UNITY_EDITOR
abstract class AnimatorPropertyDrawer : UnityEditor.PropertyDrawer
{
    class AnimatorList : List<Animator>
    {
        public bool Created;
    }

    protected static List<Animator> GetAnimators(UnityEditor.SerializedProperty property)
    {
        var controlID = GUIUtility.GetControlID(FocusType.Passive);
        var animatorList = GUIUtility.GetStateObject(typeof(AnimatorList), controlID) as AnimatorList;

        if (animatorList.Created)
        {
            return animatorList;
        }

        foreach (var obj in property.serializedObject.targetObjects)
        {
            if (obj is Component component)
            {
                var animator = component.GetComponent<Animator>();

                if (animator != null)
                {
                    animatorList.Add(animator);
                    continue;
                }
            }

            animatorList.Clear();
            break;
        }

        animatorList.Created = true;
        return animatorList;
    }
}

[UnityEditor.CustomPropertyDrawer(typeof(AnimatorStateName))]
class AnimatorStateNameDrawer : AnimatorPropertyDrawer
{
    static SortedList<string, int> m_StateNames = new SortedList<string, int>();
    static List<string> m_Options = new List<string>();
    static List<int> m_Values = new List<int>();

    static void GetStateNames(List<Animator> animators, SortedList<string, int> result)
    {
        static void GetStateNames(UnityEditor.Animations.AnimatorStateMachine stateMachine, SortedList<string, int> result)
        {
            foreach (var childState in stateMachine.states)
            {
                var hash = Animator.StringToHash(childState.state.name);
                result[childState.state.name] = hash;
            }

            foreach (var childStateMachine in stateMachine.stateMachines)
            {
                if (!string.IsNullOrEmpty(childStateMachine.stateMachine.name))
                {
                    var hash = Animator.StringToHash(childStateMachine.stateMachine.name);
                    result[childStateMachine.stateMachine.name] = hash;
                }

                GetStateNames(childStateMachine.stateMachine, result);
            }
        }

        result.Clear();

        foreach (var animator in animators)
        {
            if (animator.runtimeAnimatorController is UnityEditor.Animations.AnimatorController controller)
            {
                foreach (var layer in controller.layers)
                {
                    GetStateNames(layer.stateMachine, m_StateNames);
                }
            }
        }
    }

    public override void OnGUI(Rect position, UnityEditor.SerializedProperty property, GUIContent label)
    {
        var animators = GetAnimators(property);

        if (animators.Count <= 0)
        {
            return;
        }

        GetStateNames(animators, m_StateNames);

        m_Options.Clear();
        m_Values.Clear();

        m_Options.Add("[None]");
        m_Values.Add(0);

        foreach (var pair in m_StateNames)
        {
            m_Options.Add(pair.Key);
            m_Values.Add(pair.Value);
        }

        var selection = -1;
        var hashProperty = property.FindPropertyRelative(nameof(AnimatorStateName.m_Hash));

        UnityEditor.EditorGUI.showMixedValue = property.hasMultipleDifferentValues;

        if (!UnityEditor.EditorGUI.showMixedValue)
        {
            if (hashProperty.intValue == 0)
            {
                selection = 0;
            }
            else
            {
                selection = m_StateNames.IndexOfValue(hashProperty.intValue) + 1;

                if (selection == 0)
                {
                    selection = m_Options.Count;
                    m_Options.Add($"Unknown State {hashProperty.intValue}");
                    m_Values.Add(property.intValue);
                }
            }
        }

        UnityEditor.EditorGUI.BeginChangeCheck();

        selection = UnityEditor.EditorGUI.Popup(position, label.text, selection, m_Options.ToArray());

        if (UnityEditor.EditorGUI.EndChangeCheck())
        {
            hashProperty.intValue = m_Values[selection];
        }
    }

    public override float GetPropertyHeight(UnityEditor.SerializedProperty property, GUIContent label)
    {
        var animators = GetAnimators(property);
        return 0 < animators.Count ? base.GetPropertyHeight(property, label) : 0;
    }
}

[UnityEditor.CustomPropertyDrawer(typeof(AnimatorParameterName))]
class AnimatorParameterNameDrawer : AnimatorPropertyDrawer
{
    static SortedList<string, int> m_ParameterNames = new SortedList<string, int>();
    static List<string> m_Options = new List<string>();
    static List<int> m_Values = new List<int>();

    static void GetParameterNames(List<Animator> animators, SortedList<string, int> result)
    {
        result.Clear();

        foreach (var animator in animators)
        {
            if (animator.runtimeAnimatorController is UnityEditor.Animations.AnimatorController controller)
            {
                foreach (var parameter in controller.parameters)
                {
                    result[parameter.name] = parameter.nameHash;
                }
            }
        }
    }

    public override void OnGUI(Rect position, UnityEditor.SerializedProperty property, GUIContent label)
    {
        var animators = GetAnimators(property);

        if (animators.Count <= 0)
        {
            return;
        }

        GetParameterNames(animators, m_ParameterNames);

        m_Options.Clear();
        m_Values.Clear();

        m_Options.Add("[None]");
        m_Values.Add(0);

        foreach (var pair in m_ParameterNames)
        {
            m_Options.Add(pair.Key);
            m_Values.Add(pair.Value);
        }

        var selection = -1;
        var hashProperty = property.FindPropertyRelative(nameof(AnimatorStateName.m_Hash));

        UnityEditor.EditorGUI.showMixedValue = property.hasMultipleDifferentValues;

        if (!UnityEditor.EditorGUI.showMixedValue)
        {
            if (hashProperty.intValue == 0)
            {
                selection = 0;
            }
            else
            {
                selection = m_ParameterNames.IndexOfValue(hashProperty.intValue) + 1;

                if (selection == 0)
                {
                    selection = m_Options.Count;
                    m_Options.Add($"Unknown Parameter {hashProperty.intValue}");
                    m_Values.Add(property.intValue);
                }
            }
        }

        UnityEditor.EditorGUI.BeginChangeCheck();

        selection = UnityEditor.EditorGUI.Popup(position, label.text, selection, m_Options.ToArray());

        if (UnityEditor.EditorGUI.EndChangeCheck())
        {
            hashProperty.intValue = m_Values[selection];
        }
    }

    public override float GetPropertyHeight(UnityEditor.SerializedProperty property, GUIContent label)
    {
        var animators = GetAnimators(property);
        return 0 < animators.Count ? base.GetPropertyHeight(property, label) : 0;
    }
}
#endif // UNITY_EDITOR