生のビット表示をしたり、編集したい貴方に。

BitFlagsAttribute.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

[System.AttributeUsage( System.AttributeTargets.Field )]
public sealed class BitFlagsAttribute : PropertyAttribute {
}

BitFlagsAttributeDrawer.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEditor;

[CustomPropertyDrawer( typeof( BitFlagsAttribute ) )]
public sealed class BitFlagsAttributeDrawer : PropertyDrawer {

    int rowCount = 0;

    public override void OnGUI( Rect position, SerializedProperty property, GUIContent label ) {

        position.height = EditorGUIUtility.singleLineHeight;

        // 数字の入力欄を作成
        EditorGUI.BeginChangeCheck();
        string value_string = EditorGUI.TextField( position, "Hexadecimal", property.longValue.ToString( "X" ) );
        if ( EditorGUI.EndChangeCheck() == true ) {
            long parse_value = property.longValue;
            if ( long.TryParse( value_string, System.Globalization.NumberStyles.HexNumber, System.Globalization.CultureInfo.InvariantCulture, out parse_value ) == true ) {
                property.longValue = parse_value;
            }
        }
        position.y += EditorGUIUtility.singleLineHeight;

        // ビットボタンを出力
        float left = position.xMin + EditorGUIUtility.singleLineHeight;
        float width = position.width - ( EditorGUIUtility.singleLineHeight * 1.4f );
        float column_size = EditorGUIUtility.singleLineHeight * 2.0f;
        float column4_space = column_size * 0.1f;

        position.width = column_size;

        int row_count = 4;
        int column_count = 8;
        if ( ( width / column_size ) > 16 ) {
            row_count = 2;
            column_count = 16;
        }
        if ( ( width / column_size ) > 32 ) {
            row_count = 1;
            column_count = 32;
        }
        rowCount = row_count;
        float right = left + ( column_count - 1 ) * column_size + ( column4_space ) * ( column_count / 4 );

        position.x = right;
        int index = 0;

        uint bit_value = (uint)property.longValue;

        for ( int i = 0; i < row_count; ++i ) {

            for ( int n = 0; n < column_count; ++n ) {

                bool bit = ( ( bit_value & ( 1 << index ) ) == 0 ) ? false : true;
                EditorGUI.BeginChangeCheck();
                bool new_bit = GUI.Toggle( position, bit, index.ToString(), EditorStyles.miniButton );
                if ( EditorGUI.EndChangeCheck() == true ) {
                    if ( new_bit == true ) {
                        bit_value |= ( (uint)( 1 << index ) );
                    } else {
                        bit_value &= ~( (uint)( 1 << index ) );
                    }
                }
                position.x -= column_size;

                if ( ( index % 4 ) == 3 ) {
                    position.x -= column4_space;
                }

                ++index;
            }
            position.x = right;
            position.y += EditorGUIUtility.singleLineHeight;
        }

        property.longValue = bit_value;
    }

    // プロパティを表示するのに必要な行の高さを返します。
    public override float GetPropertyHeight( SerializedProperty property, GUIContent label ) {
        return EditorGUIUtility.singleLineHeight * ( rowCount + 1 );
    }

}

sample.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Test {
    [BitFlags]
    public uint Flags;
}