UnityEditor 实现如 BoxCollider 的编辑功能

CastShapeBase.cs

using System.Collections;
using UnityEngine;

public abstract class CastShapeBase : MonoBehaviour {

#if UNITY_EDITOR
    protected readonly Color m_gizomsColor = Color.cyan;

    protected virtual void Reset () {

    }

    protected virtual void OnDrawGizmosSelected () {

    }
#endif
}

CastBox.cs

using System.Collections;
using UnityEngine;

public class CastBox : CastShapeBase {

    public Vector3 center;
    public Vector3 size = Vector3.one;

#if UNITY_EDITOR
    protected override void Reset () {
        center = Vector3.zero;
        size = Vector3.one;
    }

    protected override void OnDrawGizmosSelected () {
        Matrix4x4 gizmosMatrixRecord = Gizmos.matrix;
        Color gizmosColorRecord = Gizmos.color;
        Gizmos.color = m_gizomsColor;
        Gizmos.matrix = transform.localToWorldMatrix;
        Gizmos.DrawWireCube(center, size);
        Gizmos.color = gizmosColorRecord;
        Gizmos.matrix = gizmosMatrixRecord;
    }
#endif
}

CastBoxEditor.cs 放置在名为 Editor 的文件夹下

#if UNITY_EDITOR
using System.Collections;
using UnityEditor;
using UnityEditor.EditorTools;
using UnityEditor.IMGUI.Controls;
using UnityEngine;

[EditorTool("Edit Cast Shape", typeof(CastBox))]
public class CastBoxTool : CastShapeTool<CastBox> {

    private readonly BoxBoundsHandle m_boundsHandle = new BoxBoundsHandle();

    protected override PrimitiveBoundsHandle boundsHandle {
        get { return m_boundsHandle; }
    }

    protected override void CopyColliderPropertiesToHandle (CastBox castShape) {
        m_boundsHandle.center = TransformColliderCenterToHandleSpace(castShape.transform, castShape.center);
        m_boundsHandle.size = Vector3.Scale(castShape.size, castShape.transform.lossyScale);
    }

    protected override void CopyHandlePropertiesToCollider (CastBox castShape) {
        castShape.center = TransformHandleCenterToColliderSpace(castShape.transform, m_boundsHandle.center);
        Vector3 size = Vector3.Scale(m_boundsHandle.size, InvertScaleVector(castShape.transform.lossyScale));
        size = new Vector3(Mathf.Abs(size.x), Mathf.Abs(size.y), Mathf.Abs(size.z));
        castShape.size = size;
    }
}


[CustomEditor(typeof(CastBox))]
[CanEditMultipleObjects]
public class CastBoxEditor : Editor {

    private SerializedProperty m_script;
    private SerializedProperty m_center;
    private SerializedProperty m_size;

    private void OnEnable () {
        m_script = serializedObject.FindProperty("m_Script");
        m_center = serializedObject.FindProperty("center");
        m_size = serializedObject.FindProperty("size");
    }

    public override void OnInspectorGUI () {
        serializedObject.Update();

        GUI.enabled = false;
        EditorGUILayout.PropertyField(m_script);
        GUI.enabled = true;
        EditorGUILayout.EditorToolbarForTarget(EditorGUIUtility.TrTempContent("Edit Shape"), target);
        EditorGUILayout.PropertyField(m_center);
        EditorGUILayout.PropertyField(m_size);

        serializedObject.ApplyModifiedProperties();
    }
}
#endif

CastShapeTool.cs 放置在名为 Editor 的文件夹下

#if UNITY_EDITOR
using System.Collections;
using System.Reflection;
using UnityEditor;
using UnityEditor.EditorTools;
using UnityEditor.IMGUI.Controls;
using UnityEngine;

public abstract class CastShapeTool<T> : EditorTool where T : CastShapeBase {

    protected readonly Color m_handleEnableColor = Color.cyan;
    protected readonly Color m_handleDisableColor = new Color(0f, 0.7f, 0.7f);

    public override GUIContent toolbarIcon {
        get {
            PropertyInfo propertyInfo = typeof(PrimitiveBoundsHandle).GetProperty("editModeButton", BindingFlags.NonPublic | BindingFlags.Static);
            return (GUIContent)propertyInfo.GetValue(null);
        }
    }

    protected abstract PrimitiveBoundsHandle boundsHandle { get; }

    protected abstract void CopyColliderPropertiesToHandle (T castShape);

    protected abstract void CopyHandlePropertiesToCollider (T castShape);

    protected Vector3 InvertScaleVector (Vector3 scaleVector) {
        for (int axis = 0; axis < 3; ++axis)
            scaleVector[axis] = scaleVector[axis] == 0f ? 0f : 1f / scaleVector[axis];

        return scaleVector;
    }

    public override void OnToolGUI (EditorWindow window) {
        foreach (var obj in targets) {
            if (!(obj is T castShape) || Mathf.Approximately(castShape.transform.lossyScale.sqrMagnitude, 0f))
                continue;

            // collider matrix is center multiplied by transform's matrix with custom postmultiplied lossy scale matrix
            using (new Handles.DrawingScope(Matrix4x4.TRS(castShape.transform.position, castShape.transform.rotation, Vector3.one))) {
                CopyColliderPropertiesToHandle(castShape);

                boundsHandle.SetColor(castShape.enabled ? m_handleEnableColor : m_handleDisableColor);

                EditorGUI.BeginChangeCheck();

                boundsHandle.DrawHandle();

                if (EditorGUI.EndChangeCheck()) {
                    Undo.RecordObject(castShape, string.Format("Modify {0}", ObjectNames.NicifyVariableName(target.GetType().Name)));
                    CopyHandlePropertiesToCollider(castShape);
                }
            }
        }
    }

    protected static Vector3 TransformColliderCenterToHandleSpace (Transform colliderTransform, Vector3 colliderCenter) {
        return Handles.inverseMatrix * (colliderTransform.localToWorldMatrix * colliderCenter);
    }

    protected static Vector3 TransformHandleCenterToColliderSpace (Transform colliderTransform, Vector3 handleCenter) {
        return colliderTransform.localToWorldMatrix.inverse * (Handles.matrix * handleCenter);
    }
}
#endif