Add PercentageVariable and PercentageReference

Author: adamgraham

Editor/Variables/PercentageReferencePropertyDrawer.cs

@@ -0,0 +1,67 @@
+using UnityEditor;
+using UnityEngine;
+
+namespace Zigurous.Architecture.Editor
+{
+    [CustomPropertyDrawer(typeof(PercentageReference), true)]
+    public class PercentageReferencePropertyDrawer : PropertyDrawer
+    {
+        private readonly string[] popupOptions = { "Fixed Value", "Variable" };
+        private static GUIStyle popupStyle;
+
+        public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
+        {
+            if (popupStyle == null)
+            {
+                popupStyle = new GUIStyle(GUI.skin.GetStyle("PaneOptions"));
+                popupStyle.imagePosition = ImagePosition.ImageOnly;
+            }
+
+            SerializedProperty useVariable = property.FindPropertyRelative("useVariable");
+            SerializedProperty variable = property.FindPropertyRelative("variable");
+            SerializedProperty fixedValue = property.FindPropertyRelative("fixedValue");
+
+            label = EditorGUI.BeginProperty(position, label, property);
+            position = EditorGUI.PrefixLabel(position, label);
+
+            int indent = EditorGUI.indentLevel;
+            EditorGUI.indentLevel = 0;
+
+            Rect popupRect = new Rect(position);
+            popupRect.width = popupStyle.fixedWidth + popupStyle.margin.right;
+            popupRect.height = popupStyle.fixedHeight;
+            popupRect.x += position.width - popupRect.width;
+            popupRect.y += (EditorGUIUtility.singleLineHeight - popupStyle.fixedHeight) / 2f;
+            position.width -= popupRect.width;
+
+            EditorGUI.BeginChangeCheck();
+
+            int result = EditorGUI.Popup(popupRect, useVariable.boolValue ? 1 : 0, popupOptions, popupStyle);
+            useVariable.boolValue = result == 1;
+
+            if (useVariable.boolValue) {
+                EditorGUI.PropertyField(position, variable, GUIContent.none, true);
+            } else {
+                fixedValue.floatValue = EditorGUI.Slider(position, fixedValue.floatValue, 0f, 1f);
+            }
+
+            if (EditorGUI.EndChangeCheck()) {
+                property.serializedObject.ApplyModifiedProperties();
+            }
+
+            EditorGUI.indentLevel = indent;
+            EditorGUI.EndProperty();
+        }
+
+        public override float GetPropertyHeight(SerializedProperty property, GUIContent label)
+        {
+            SerializedProperty useVariable = property.FindPropertyRelative("useVariable");
+            SerializedProperty variable = property.FindPropertyRelative("variable");
+            SerializedProperty fixedValue = property.FindPropertyRelative("fixedValue");
+
+            return EditorGUI.GetPropertyHeight(useVariable.boolValue ? variable : fixedValue, true);
+        }
+
+    }
+
+}

Editor/Variables/PercentageReferencePropertyDrawer.cs.meta

@@ -0,0 +1,34 @@
+namespace Zigurous.Architecture
+{
+    /// <summary>
+    /// A reference to a percentage value, either a constant or <see cref="PercentageVariable"/>.
+    /// </summary>
+    [System.Serializable]
+    public class PercentageReference : ValueReference<float, PercentageVariable>
+    {
+        /// <summary>
+        /// Creates a new percentage reference.
+        /// </summary>
+        public PercentageReference() {}
+
+        /// <summary>
+        /// Creates a new percentage reference with the fixed value.
+        /// </summary>
+        /// <param name="value">The fixed value to set.</param>
+        public PercentageReference(float value) : base(value) {}
+
+        /// <summary>
+        /// Creates a new percentage reference to the variable value.
+        /// </summary>
+        /// <param name="variable">The variable to reference.</param>
+        public PercentageReference(PercentageVariable variable) : base(variable) {}
+
+        /// <summary>
+        /// Implicitly converts the reference to a float.
+        /// </summary>
+        /// <param name="reference">The reference to convert.</param>
+        /// <returns>The float value.</returns>
+        public static implicit operator float(PercentageReference reference) => reference.value;
+    }
+
+}

Runtime/Variables/PercentageReference.cs

@@ -0,0 +1,30 @@
+using UnityEngine;
+
+namespace Zigurous.Architecture
+{
+    /// <summary>
+    /// A percentage variable saved as a ScriptableObject. Percentages are float
+    /// values in the range [0..1].
+    /// </summary>
+    [CreateAssetMenu(menuName = "Zigurous/Variables/Percentage")]
+    [HelpURL("https://docs.zigurous.com/com.zigurous.architecture/api/Zigurous.Architecture/PercentageVariable")]
+    public class PercentageVariable : ScriptableVariable<float>
+    {
+        /// <summary>
+        /// The value of the variable.
+        /// </summary>
+        [SerializeField]
+        [Tooltip("The value of the variable.")]
+        [Range(0f, 1f)]
+        private float m_Value;
+
+        /// <inheritdoc/>
+        public override float value
+        {
+            get => m_Value;
+            set => m_Value = value;
+        }
+
+    }
+
+}