{"id":867,"date":"2019-12-12T00:28:19","date_gmt":"2019-12-12T00:28:19","guid":{"rendered":"https:\/\/www.danielparente.net\/en\/2019\/12\/12\/unity-3d-rts-style-unit-selection\/"},"modified":"2019-12-12T00:28:19","modified_gmt":"2019-12-12T00:28:19","slug":"unity-3d-rts-style-unit-selection","status":"publish","type":"post","link":"https:\/\/www.danielparente.net\/en\/2019\/12\/12\/unity-3d-rts-style-unit-selection\/","title":{"rendered":"Unity 3D RTS Style Unit Selection"},"content":{"rendered":"

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\n<\/p>\n

\n

In this post I will be showing how to create a RTS (Real-Time Strategy) box style selection in Unity 3D<\/a>.<\/p>\n

So let’s begin!<\/p>\n

Step 1: Create the necessary scripts<\/h3>\n

This post features 2 scripts:<\/p>\n

SC_Selectable.cs<\/strong><\/p>\n

using System.Collections;
\nusing System.Collections.Generic;
\nusing UnityEngine;
\n
\npublic class SC_Selectable : MonoBehaviour
\n{
\n    public Renderer[] renderers; \/\/Assign all child Mesh Renderers
\n
\n    public Bounds GetObjectBounds()
\n    {
\n        Bounds totalBounds = new Bounds();
\n
\n        for(int i = 0; i < renderers.Length; i++)
\n        {
\n            if(totalBounds.center == Vector3.zero)
\n            {
\n                totalBounds = renderers[i].bounds;
\n            }
\n            else
\n            {
\n                totalBounds.Encapsulate(renderers[i].bounds);
\n            }
\n        }
\n
\n        return totalBounds;
\n    }
\n
\n    void OnEnable()
\n    {
\n        \/\/Add this Object to global list
\n        if (!SC_SelectionManager.selectables.Contains(this))
\n        {
\n            SC_SelectionManager.selectables.Add(this);
\n        }
\n    }
\n
\n    void OnDisable()
\n    {
\n        \/\/Remove this Object from global list
\n        if (SC_SelectionManager.selectables.Contains(this))
\n        {
\n            SC_SelectionManager.selectables.Remove(this);
\n        }
\n    }
\n}<\/code><\/pre>\n
SC_SelectionManager.cs<\/strong><\/p>\n
using System.Collections;
\nusing System.Collections.Generic;
\nusing UnityEngine;
\n
\npublic class SC_SelectionManager : MonoBehaviour
\n{
\n    public Texture topLeftBorder;
\n    public Texture bottomLeftBorder;
\n    public Texture topRightBorder;
\n    public Texture bottomRightBorder;
\n
\n    Texture2D _borderTexture;
\n    Texture2D borderTexture
\n    {
\n        get
\n        {
\n            if (_borderTexture == null)
\n            {
\n                _borderTexture = new Texture2D(1, 1);
\n                _borderTexture.SetPixel(0, 0, Color.white);
\n                _borderTexture.Apply();
\n            }
\n
\n            return _borderTexture;
\n        }
\n    }
\n
\n    bool selectionStarted = false;
\n    Vector3 mousePosition1;
\n
\n    public static List<SC_Selectable> selectables = new List<SC_Selectable>();
\n    List<int> selectedObjects = new List<int>();
\n
\n    \/\/ Update is called once per frame
\n    void Update()
\n    {
\n        \/\/ Begin selection
\n        if (Input.GetMouseButtonDown(0))
\n        {
\n            selectionStarted = true;
\n            mousePosition1 = Input.mousePosition;
\n        }
\n        \/\/ End selection
\n        if (Input.GetMouseButtonUp(0))
\n        {
\n            selectionStarted = false;
\n        }
\n
\n        if (selectionStarted)
\n        {
\n            \/\/ Detect which Objects are inside selection rectangle
\n            Camera camera = Camera.main;
\n            selectedObjects.Clear();
\n            for (int i = 0; i < selectables.Count; i++)
\n            {
\n                Bounds viewportBounds = GetViewportBounds(camera, mousePosition1, Input.mousePosition);
\n                if (viewportBounds.Contains(camera.WorldToViewportPoint(selectables[i].transform.position)))
\n                {
\n                    selectedObjects.Add(i);
\n                }
\n            }
\n        }
\n    }
\n
\n    void OnGUI()
\n    {
\n        if (selectionStarted)
\n        {
\n            Rect rect = GetScreenRect(mousePosition1, Input.mousePosition);
\n            DrawScreenRectBorder(rect, 2, Color.cyan);
\n        }
\n
\n        \/\/ Draw selection edges
\n        if(selectedObjects.Count > 0)
\n        {
\n            Camera camera = Camera.main;
\n            for (int i = 0; i < selectedObjects.Count; i++)
\n            {
\n                DrawSelectionIndicator(camera, selectables[selectedObjects[i]].GetObjectBounds());
\n            }
\n        }
\n    }
\n
\n    void DrawScreenRectBorder(Rect rect, float thickness, Color color)
\n    {
\n        \/\/ Top
\n        DrawBorderRect(new Rect(rect.xMin, rect.yMin, rect.width, thickness), color);
\n        \/\/ Left
\n        DrawBorderRect(new Rect(rect.xMin, rect.yMin, thickness, rect.height), color);
\n        \/\/ Right
\n        DrawBorderRect(new Rect(rect.xMax - thickness, rect.yMin, thickness, rect.height), color);
\n        \/\/ Bottom
\n        DrawBorderRect(new Rect(rect.xMin, rect.yMax - thickness, rect.width, thickness), color);
\n    }
\n
\n    void DrawBorderRect(Rect rect, Color color)
\n    {
\n        GUI.color = color;
\n        GUI.DrawTexture(rect, borderTexture);
\n        GUI.color = Color.white;
\n    }
\n
\n    Rect GetScreenRect(Vector3 screenPosition1, Vector3 screenPosition2)
\n    {
\n        \/\/ Move origin from bottom left to top left
\n        screenPosition1.y = Screen.height - screenPosition1.y;
\n        screenPosition2.y = Screen.height - screenPosition2.y;
\n        \/\/ Calculate corners
\n        var topLeft = Vector3.Min(screenPosition1, screenPosition2);
\n        var bottomRight = Vector3.Max(screenPosition1, screenPosition2);
\n        \/\/ Create Rect
\n        return Rect.MinMaxRect(topLeft.x, topLeft.y, bottomRight.x, bottomRight.y);
\n    }
\n
\n    Bounds GetViewportBounds(Camera camera, Vector3 screenPosition1, Vector3 screenPosition2)
\n    {
\n        Vector3 v1 = camera.ScreenToViewportPoint(screenPosition1);
\n        Vector3 v2 = camera.ScreenToViewportPoint(screenPosition2);
\n        Vector3 min = Vector3.Min(v1, v2);
\n        Vector3 max = Vector3.Max(v1, v2);
\n        min.z = camera.nearClipPlane;
\n        max.z = camera.farClipPlane;
\n
\n        Bounds bounds = new Bounds();
\n        bounds.SetMinMax(min, max);
\n        return bounds;
\n    }
\n
\n    void DrawSelectionIndicator(Camera camera, Bounds bounds)
\n    {
\n        Vector3 boundPoint1 = bounds.min;
\n        Vector3 boundPoint2 = bounds.max;
\n        Vector3 boundPoint3 = new Vector3(boundPoint1.x, boundPoint1.y, boundPoint2.z);
\n        Vector3 boundPoint4 = new Vector3(boundPoint1.x, boundPoint2.y, boundPoint1.z);
\n        Vector3 boundPoint5 = new Vector3(boundPoint2.x, boundPoint1.y, boundPoint1.z);
\n        Vector3 boundPoint6 = new Vector3(boundPoint1.x, boundPoint2.y, boundPoint2.z);
\n        Vector3 boundPoint7 = new Vector3(boundPoint2.x, boundPoint1.y, boundPoint2.z);
\n        Vector3 boundPoint8 = new Vector3(boundPoint2.x, boundPoint2.y, boundPoint1.z);
\n
\n        Vector2[] screenPoints = new Vector2[8];
\n        screenPoints[0] = camera.WorldToScreenPoint(boundPoint1);
\n        screenPoints[1] = camera.WorldToScreenPoint(boundPoint2);
\n        screenPoints[2] = camera.WorldToScreenPoint(boundPoint3);
\n        screenPoints[3] = camera.WorldToScreenPoint(boundPoint4);
\n        screenPoints[4] = camera.WorldToScreenPoint(boundPoint5);
\n        screenPoints[5] = camera.WorldToScreenPoint(boundPoint6);
\n        screenPoints[6] = camera.WorldToScreenPoint(boundPoint7);
\n        screenPoints[7] = camera.WorldToScreenPoint(boundPoint8);
\n
\n        Vector2 topLeftPosition = Vector2.zero;
\n        Vector2 topRightPosition = Vector2.zero;
\n        Vector2 bottomLeftPosition = Vector2.zero;
\n        Vector2 bottomRightPosition = Vector2.zero;
\n
\n        for (int a = 0; a < screenPoints.Length; a++)
\n        {
\n            \/\/Top Left
\n            if (topLeftPosition.x == 0 || topLeftPosition.x > screenPoints[a].x)
\n            {
\n                topLeftPosition.x = screenPoints[a].x;
\n            }
\n            if (topLeftPosition.y == 0 || topLeftPosition.y > Screen.height - screenPoints[a].y)
\n            {
\n                topLeftPosition.y = Screen.height - screenPoints[a].y;
\n            }
\n            \/\/Top Right
\n            if (topRightPosition.x == 0 || topRightPosition.x < screenPoints[a].x)
\n            {
\n                topRightPosition.x = screenPoints[a].x;
\n            }
\n            if (topRightPosition.y == 0 || topRightPosition.y > Screen.height - screenPoints[a].y)
\n            {
\n                topRightPosition.y = Screen.height - screenPoints[a].y;
\n            }
\n            \/\/Bottom Left
\n            if (bottomLeftPosition.x == 0 || bottomLeftPosition.x > screenPoints[a].x)
\n            {
\n                bottomLeftPosition.x = screenPoints[a].x;
\n            }
\n            if (bottomLeftPosition.y == 0 || bottomLeftPosition.y < Screen.height - screenPoints[a].y)
\n            {
\n                bottomLeftPosition.y = Screen.height - screenPoints[a].y;
\n            }
\n            \/\/Bottom Right
\n            if (bottomRightPosition.x == 0 || bottomRightPosition.x < screenPoints[a].x)
\n            {
\n                bottomRightPosition.x = screenPoints[a].x;
\n            }
\n            if (bottomRightPosition.y == 0 || bottomRightPosition.y < Screen.height - screenPoints[a].y)
\n            {
\n                bottomRightPosition.y = Screen.height - screenPoints[a].y;
\n            }
\n        }
\n
\n        GUI.DrawTexture(new Rect(topLeftPosition.x - 16, topLeftPosition.y - 16, 16, 16), topLeftBorder);
\n        GUI.DrawTexture(new Rect(topRightPosition.x, topRightPosition.y - 16, 16, 16), topRightBorder);
\n        GUI.DrawTexture(new Rect(bottomLeftPosition.x - 16, bottomLeftPosition.y, 16, 16), bottomLeftBorder);
\n        GUI.DrawTexture(new Rect(bottomRightPosition.x, bottomRightPosition.y, 16, 16), bottomRightBorder);
\n    }
\n}<\/code><\/pre>\n
Step 2: Setup RTS Selection<\/h3>\n