HeavenStudioPlus/Assets/Plugins/com.unity.uiextensions/Runtime/Scripts/Controls/SelectionBox/SelectionBox.cs
2022-01-05 19:11:33 -05:00

440 lines
16 KiB
C#

///Original Credit Korindian
///Sourced from - http://forum.unity3d.com/threads/rts-style-drag-selection-box.265739/
///Updated Credit BenZed
///Sourced from - http://forum.unity3d.com/threads/color-picker.267043/
/*
* What the SelectionBox component does is allow the game player to select objects using an RTS style click and drag interface:
*
* We want to be able to select Game Objects of any type,
* We want to be able to drag select a group of game objects to select them,
* We want to be able to hold the shift key and drag select a group of game objects to add them to the current selection,
* We want to be able to single click a game object to select it,
* We want to be able to hold the shift key and single click a game object to add it to the current selection,
* We want to be able to hold the shift key and single click an already selected game object to remove it from the current selection.
*
* Most importantly, we want this behaviour to work with UI, 2D or 3D gameObjects, so it has to be smart about considering their respective screen spaces.
*
* Add this component to a Gameobject with a Canvas with RenderMode.ScreenSpaceOverlay
* And implement the IBoxSelectable interface on any MonoBehaviour to make it selectable.
*
* Improvements that could be made:
*
* Control clicking a game object to select all objects of that type or tag.
* Compatibility with Canvas Scaling
* Filtering single click selections of objects occupying the same space. (So that, for example, you're only click selecting the game object found closest to the camera)
*
*/
using System.Collections.Generic;
using UnityEngine.Events;
namespace UnityEngine.UI.Extensions
{
[RequireComponent(typeof(Canvas))]
[AddComponentMenu("UI/Extensions/Selection Box")]
public class SelectionBox : MonoBehaviour
{
// The color of the selection box.
public Color color;
// An optional parameter, but you can add a sprite to the selection box to give it a border or a stylized look.
// It's suggested you use a monochrome sprite so that the selection
// Box color is still relevant.
public Sprite art;
// Will store the location of wherever we first click before dragging.
private Vector2 origin;
// A rectTransform set by the User that can limit which part of the screen is eligible for drag selection
public RectTransform selectionMask;
//Stores the rectTransform connected to the generated gameObject being used for the selection box visuals
private RectTransform boxRect;
// Stores all of the selectable game objects
private IBoxSelectable[] selectables;
// A secondary storage of objects that the user can manually set.
private MonoBehaviour[] selectableGroup;
//Stores the selectable that was touched when the mouse button was pressed down
private IBoxSelectable clickedBeforeDrag;
//Stores the selectable that was touched when the mouse button was released
private IBoxSelectable clickedAfterDrag;
//Custom UnityEvent so we can add Listeners to this instance when Selections are changed.
public class SelectionEvent : UnityEvent<IBoxSelectable[]> {}
public SelectionEvent onSelectionChange = new SelectionEvent();
//Ensures that the canvas that this component is attached to is set to the correct render mode. If not, it will not render the selection box properly.
void ValidateCanvas(){
var canvas = gameObject.GetComponent<Canvas>();
if (canvas.renderMode != RenderMode.ScreenSpaceOverlay) {
throw new System.Exception("SelectionBox component must be placed on a canvas in Screen Space Overlay mode.");
}
var canvasScaler = gameObject.GetComponent<CanvasScaler>();
if (canvasScaler && canvasScaler.enabled && (!Mathf.Approximately(canvasScaler.scaleFactor, 1f) || canvasScaler.uiScaleMode != CanvasScaler.ScaleMode.ConstantPixelSize)) {
Destroy(canvasScaler);
Debug.LogWarning("SelectionBox component is on a gameObject with a Canvas Scaler component. As of now, Canvas Scalers without the default settings throw off the coordinates of the selection box. Canvas Scaler has been removed.");
}
}
/*
* The user can manually set a group of objects with monoBehaviours to be the pool of objects considered to be selectable. The benefits of this are two fold:
*
* 1) The default behaviour is to check every game object in the scene, which is much slower.
* 2) The user can filter which objects should be selectable, for example units versus menu selections
*
*/
void SetSelectableGroup(IEnumerable<MonoBehaviour> behaviourCollection) {
// If null, the selectionbox reverts to it's default behaviour
if (behaviourCollection == null) {
selectableGroup = null;
return;
}
//Runs a double check to ensure each of the objects in the collection can be selectable, and doesn't include them if not.
var behaviourList = new List<MonoBehaviour>();
foreach(var behaviour in behaviourCollection) {
if (behaviour as IBoxSelectable != null) {
behaviourList.Add (behaviour);
}
}
selectableGroup = behaviourList.ToArray();
}
void CreateBoxRect(){
var selectionBoxGO = new GameObject();
selectionBoxGO.name = "Selection Box";
selectionBoxGO.transform.parent = transform;
selectionBoxGO.AddComponent<Image>();
boxRect = selectionBoxGO.transform as RectTransform;
}
//Set all of the relevant rectTransform properties to zero,
//finally deactivates the boxRect gameobject since it doesn't
//need to be enabled when not in a selection action.
void ResetBoxRect(){
//Update the art and color on the off chance they've changed
Image image = boxRect.GetComponent<Image>();
image.color = color;
image.sprite = art;
origin = Vector2.zero;
boxRect.anchoredPosition = Vector2.zero;
boxRect.sizeDelta = Vector2.zero;
boxRect.anchorMax = Vector2.zero;
boxRect.anchorMin = Vector2.zero;
boxRect.pivot = Vector2.zero;
boxRect.gameObject.SetActive(false);
}
void BeginSelection(){
// Click somewhere in the Game View.
if (!UIExtensionsInputManager.GetMouseButtonDown(0))
return;
//The boxRect will be inactive up until the point we start selecting
boxRect.gameObject.SetActive(true);
// Get the initial click position of the mouse.
origin = new Vector2(UIExtensionsInputManager.MousePosition.x, UIExtensionsInputManager.MousePosition.y);
//If the initial click point is not inside the selection mask, we abort the selection
if (!PointIsValidAgainstSelectionMask(origin)) {
ResetBoxRect();
return;
}
// The anchor is set to the same place.
boxRect.anchoredPosition = origin;
MonoBehaviour[] behavioursToGetSelectionsFrom;
// If we do not have a group of selectables already set, we'll just loop through every object that's a monobehaviour, and look for selectable interfaces in them
if (selectableGroup == null) {
behavioursToGetSelectionsFrom = GameObject.FindObjectsOfType<MonoBehaviour>();
} else {
behavioursToGetSelectionsFrom = selectableGroup;
}
//Temporary list to store the found selectables before converting to the main selectables array
List<IBoxSelectable> selectableList = new List<IBoxSelectable>();
foreach (MonoBehaviour behaviour in behavioursToGetSelectionsFrom) {
//If the behaviour implements the selectable interface, we add it to the selectable list
IBoxSelectable selectable = behaviour as IBoxSelectable;
if (selectable != null) {
selectableList.Add (selectable);
//We're using left shift to act as the "Add To Selection" command. So if left shift isn't pressed, we want everything to begin deselected
if (!UIExtensionsInputManager.GetKey (KeyCode.LeftShift)) {
selectable.selected = false;
}
}
}
selectables = selectableList.ToArray();
//For single-click actions, we need to get the selectable that was clicked when selection began (if any)
clickedBeforeDrag = GetSelectableAtMousePosition();
}
bool PointIsValidAgainstSelectionMask(Vector2 screenPoint){
//If there is no selection mask, any point is valid
if (!selectionMask) {
return true;
}
Camera screenPointCamera = GetScreenPointCamera(selectionMask);
return RectTransformUtility.RectangleContainsScreenPoint(selectionMask, screenPoint, screenPointCamera);
}
IBoxSelectable GetSelectableAtMousePosition() {
//Firstly, we cannot click on something that is not inside the selection mask (if we have one)
if (!PointIsValidAgainstSelectionMask(UIExtensionsInputManager.MousePosition)) {
return null;
}
//This gets a bit tricky, because we have to make considerations depending on the hierarchy of the selectable's gameObject
foreach (var selectable in selectables) {
//First we check to see if the selectable has a rectTransform
var rectTransform = (selectable.transform as RectTransform);
if (rectTransform) {
//Because if it does, the camera we use to calculate it's screen point will vary
var screenCamera = GetScreenPointCamera(rectTransform);
//Once we've found the rendering camera, we check if the selectables rectTransform contains the click. That way we
//Can click anywhere on a rectTransform to select it.
if (RectTransformUtility.RectangleContainsScreenPoint(rectTransform, UIExtensionsInputManager.MousePosition, screenCamera)) {
//And if it does, we select it and send it back
return selectable;
}
} else {
//If it doesn't have a rectTransform, we need to get the radius so we can use it as an area around the center to detect a click.
//This works because a 2D or 3D renderer will both return a radius
var radius = selectable.transform.GetComponent<UnityEngine.Renderer>().bounds.extents.magnitude;
var selectableScreenPoint = GetScreenPointOfSelectable(selectable);
//Check that the click fits within the screen-radius of the selectable
if (Vector2.Distance(selectableScreenPoint, UIExtensionsInputManager.MousePosition) <= radius) {
//And if it does, we select it and send it back
return selectable;
}
}
}
return null;
}
void DragSelection(){
//Return if we're not dragging or if the selection has been aborted (BoxRect disabled)
if (!UIExtensionsInputManager.GetMouseButton(0) || !boxRect.gameObject.activeSelf)
return;
// Store the current mouse position in screen space.
Vector2 currentMousePosition = new Vector2(UIExtensionsInputManager.MousePosition.x, UIExtensionsInputManager.MousePosition.y);
// How far have we moved the mouse?
Vector2 difference = currentMousePosition - origin;
// Copy the initial click position to a new variable. Using the original variable will cause
// the anchor to move around to wherever the current mouse position is,
// which isn't desirable.
Vector2 startPoint = origin;
// The following code accounts for dragging in various directions.
if (difference.x < 0)
{
startPoint.x = currentMousePosition.x;
difference.x = -difference.x;
}
if (difference.y < 0)
{
startPoint.y = currentMousePosition.y;
difference.y = -difference.y;
}
// Set the anchor, width and height every frame.
boxRect.anchoredPosition = startPoint;
boxRect.sizeDelta = difference;
//Then we check our list of Selectables to see if they're being preselected or not.
foreach(var selectable in selectables) {
Vector3 screenPoint = GetScreenPointOfSelectable(selectable);
//If the box Rect contains the selectables screen point and that point is inside a valid selection mask, it's being preselected, otherwise it is not.
selectable.preSelected = RectTransformUtility.RectangleContainsScreenPoint(boxRect, screenPoint, null) && PointIsValidAgainstSelectionMask(screenPoint);
}
//Finally, since it's possible for our first clicked object to not be within the bounds of the selection box
//If it exists, we always ensure that it is preselected.
if (clickedBeforeDrag != null) {
clickedBeforeDrag.preSelected = true;
}
}
void ApplySingleClickDeselection(){
//If we didn't touch anything with the original mouse press, we don't need to continue checking
if (clickedBeforeDrag == null)
return;
//If we clicked a selectable without dragging, and that selectable was previously selected, we must be trying to deselect it.
if (clickedAfterDrag != null && clickedBeforeDrag.selected && clickedBeforeDrag.transform == clickedAfterDrag.transform ) {
clickedBeforeDrag.selected = false;
clickedBeforeDrag.preSelected = false;
}
}
void ApplyPreSelections(){
foreach(var selectable in selectables) {
//If the selectable was preSelected, we finalize it as selected.
if (selectable.preSelected) {
selectable.selected = true;
selectable.preSelected = false;
}
}
}
Vector2 GetScreenPointOfSelectable(IBoxSelectable selectable) {
//Getting the screen point requires it's own function, because we have to take into consideration the selectables hierarchy.
//Cast the transform as a rectTransform
var rectTransform = selectable.transform as RectTransform;
//If it has a rectTransform component, it must be in the hierarchy of a canvas, somewhere.
if (rectTransform) {
//And the camera used to calculate it's screen point will vary.
Camera renderingCamera = GetScreenPointCamera(rectTransform);
return RectTransformUtility.WorldToScreenPoint(renderingCamera, selectable.transform.position);
}
//If it's no in the hierarchy of a canvas, the regular Camera.main.WorldToScreenPoint will do.
return Camera.main.WorldToScreenPoint(selectable.transform.position);
}
/*
* Finding the camera used to calculate the screenPoint of an object causes a couple of problems:
*
* If it has a rectTransform, the root Canvas that the rectTransform is a descendant of will give unusable
* screen points depending on the Canvas.RenderMode, if we don't do any further calculation.
*
* This function solves that problem.
*/
Camera GetScreenPointCamera(RectTransform rectTransform) {
Canvas rootCanvas = null;
RectTransform rectCheck = rectTransform;
//We're going to check all the canvases in the hierarchy of this rectTransform until we find the root.
do {
rootCanvas = rectCheck.GetComponent<Canvas>();
//If we found a canvas on this Object, and it's not the rootCanvas, then we don't want to keep it
if (rootCanvas && !rootCanvas.isRootCanvas) {
rootCanvas = null;
}
//Then we promote the rect we're checking to it's parent.
rectCheck = (RectTransform)rectCheck.parent;
} while (rootCanvas == null);
//Once we've found the root Canvas, we return a camera depending on it's render mode.
switch (rootCanvas.renderMode) {
case RenderMode.ScreenSpaceOverlay:
//If we send back a camera when set to screen space overlay, the coordinates will not be accurate. If we return null, they will be.
return null;
case RenderMode.ScreenSpaceCamera:
//If it's set to screen space we use the world Camera that the Canvas is using.
//If it doesn't have one set, however, we have to send back the current camera. otherwise the coordinates will not be accurate.
return (rootCanvas.worldCamera) ? rootCanvas.worldCamera : Camera.main;
default:
case RenderMode.WorldSpace:
//World space always uses the current camera.
return Camera.main;
}
}
public IBoxSelectable[] GetAllSelected(){
if (selectables == null) {
return new IBoxSelectable[0];
}
var selectedList = new List<IBoxSelectable>();
foreach(var selectable in selectables) {
if (selectable.selected) {
selectedList.Add (selectable);
}
}
return selectedList.ToArray();
}
void EndSelection(){
//Get out if we haven't finished selecting, or if the selection has been aborted (boxRect disabled)
if (!UIExtensionsInputManager.GetMouseButtonUp(0) || !boxRect.gameObject.activeSelf)
return;
clickedAfterDrag = GetSelectableAtMousePosition();
ApplySingleClickDeselection();
ApplyPreSelections();
ResetBoxRect();
onSelectionChange.Invoke(GetAllSelected());
}
void Start(){
ValidateCanvas();
CreateBoxRect();
ResetBoxRect();
}
void Update() {
BeginSelection ();
DragSelection ();
EndSelection ();
}
}
}