Sélection d'unités de style RTS pour Unity

Dans ce didacticiel, je vais montrer comment créer une sélection d'unités de type boîte RTS (Real-Time Strategy) dans Unity.

Sharp Coder Lecteur vidéo

Alors commençons !

Étape 1: Créez les scripts nécessaires

Cet article présente 2 scripts:

SC_Selectable.cs

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

public class SC_Selectable : MonoBehaviour
{
    public Renderer[] renderers; //Assign all child Mesh Renderers

    public Bounds GetObjectBounds()
    {
        Bounds totalBounds = new Bounds();

        for(int i = 0; i < renderers.Length; i++)
        {
            if(totalBounds.center == Vector3.zero)
            {
                totalBounds = renderers[i].bounds;
            }
            else
            {
                totalBounds.Encapsulate(renderers[i].bounds);
            }
        }

        return totalBounds;
    }

    void OnEnable()
    {
        //Add this Object to global list
        if (!SC_SelectionManager.selectables.Contains(this))
        {
            SC_SelectionManager.selectables.Add(this);
        }
    }

    void OnDisable()
    {
        //Remove this Object from global list
        if (SC_SelectionManager.selectables.Contains(this))
        {
            SC_SelectionManager.selectables.Remove(this);
        }
    }
}

SC_SelectionManager.cs

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

public class SC_SelectionManager : MonoBehaviour
{
    public Texture topLeftBorder;
    public Texture bottomLeftBorder;
    public Texture topRightBorder;
    public Texture bottomRightBorder;

    Texture2D _borderTexture;
    Texture2D borderTexture
    {
        get
        {
            if (_borderTexture == null)
            {
                _borderTexture = new Texture2D(1, 1);
                _borderTexture.SetPixel(0, 0, Color.white);
                _borderTexture.Apply();
            }

            return _borderTexture;
        }
    }

    bool selectionStarted = false;
    Vector3 mousePosition1;

    public static List<SC_Selectable> selectables = new List<SC_Selectable>();
    List<int> selectedObjects = new List<int>();

    // Update is called once per frame
    void Update()
    {
        // Begin selection
        if (Input.GetMouseButtonDown(0))
        {
            selectionStarted = true;
            mousePosition1 = Input.mousePosition;
        }
        // End selection
        if (Input.GetMouseButtonUp(0))
        {
            selectionStarted = false;
        }

        if (selectionStarted)
        {
            // Detect which Objects are inside selection rectangle
            Camera camera = Camera.main;
            selectedObjects.Clear();
            for (int i = 0; i < selectables.Count; i++)
            {
                Bounds viewportBounds = GetViewportBounds(camera, mousePosition1, Input.mousePosition);
                if (viewportBounds.Contains(camera.WorldToViewportPoint(selectables[i].transform.position)))
                {
                    selectedObjects.Add(i);
                }
            }
        }
    }

    void OnGUI()
    {
        if (selectionStarted)
        {
            Rect rect = GetScreenRect(mousePosition1, Input.mousePosition);
            DrawScreenRectBorder(rect, 2, Color.cyan);
        }

        // Draw selection edges
        if(selectedObjects.Count > 0)
        {
            Camera camera = Camera.main;
            for (int i = 0; i < selectedObjects.Count; i++)
            {
                DrawSelectionIndicator(camera, selectables[selectedObjects[i]].GetObjectBounds());
            }
        }
    }

    void DrawScreenRectBorder(Rect rect, float thickness, Color color)
    {
        // Top
        DrawBorderRect(new Rect(rect.xMin, rect.yMin, rect.width, thickness), color);
        // Left
        DrawBorderRect(new Rect(rect.xMin, rect.yMin, thickness, rect.height), color);
        // Right
        DrawBorderRect(new Rect(rect.xMax - thickness, rect.yMin, thickness, rect.height), color);
        // Bottom
        DrawBorderRect(new Rect(rect.xMin, rect.yMax - thickness, rect.width, thickness), color);
    }

    void DrawBorderRect(Rect rect, Color color)
    {
        GUI.color = color;
        GUI.DrawTexture(rect, borderTexture);
        GUI.color = Color.white;
    }

    Rect GetScreenRect(Vector3 screenPosition1, Vector3 screenPosition2)
    {
        // Move origin from bottom left to top left
        screenPosition1.y = Screen.height - screenPosition1.y;
        screenPosition2.y = Screen.height - screenPosition2.y;
        // Calculate corners
        var topLeft = Vector3.Min(screenPosition1, screenPosition2);
        var bottomRight = Vector3.Max(screenPosition1, screenPosition2);
        // Create Rect
        return Rect.MinMaxRect(topLeft.x, topLeft.y, bottomRight.x, bottomRight.y);
    }

    Bounds GetViewportBounds(Camera camera, Vector3 screenPosition1, Vector3 screenPosition2)
    {
        Vector3 v1 = camera.ScreenToViewportPoint(screenPosition1);
        Vector3 v2 = camera.ScreenToViewportPoint(screenPosition2);
        Vector3 min = Vector3.Min(v1, v2);
        Vector3 max = Vector3.Max(v1, v2);
        min.z = camera.nearClipPlane;
        max.z = camera.farClipPlane;

        Bounds bounds = new Bounds();
        bounds.SetMinMax(min, max);
        return bounds;
    }

    void DrawSelectionIndicator(Camera camera, Bounds bounds)
    {
        Vector3 boundPoint1 = bounds.min;
        Vector3 boundPoint2 = bounds.max;
        Vector3 boundPoint3 = new Vector3(boundPoint1.x, boundPoint1.y, boundPoint2.z);
        Vector3 boundPoint4 = new Vector3(boundPoint1.x, boundPoint2.y, boundPoint1.z);
        Vector3 boundPoint5 = new Vector3(boundPoint2.x, boundPoint1.y, boundPoint1.z);
        Vector3 boundPoint6 = new Vector3(boundPoint1.x, boundPoint2.y, boundPoint2.z);
        Vector3 boundPoint7 = new Vector3(boundPoint2.x, boundPoint1.y, boundPoint2.z);
        Vector3 boundPoint8 = new Vector3(boundPoint2.x, boundPoint2.y, boundPoint1.z);

        Vector2[] screenPoints = new Vector2[8];
        screenPoints[0] = camera.WorldToScreenPoint(boundPoint1);
        screenPoints[1] = camera.WorldToScreenPoint(boundPoint2);
        screenPoints[2] = camera.WorldToScreenPoint(boundPoint3);
        screenPoints[3] = camera.WorldToScreenPoint(boundPoint4);
        screenPoints[4] = camera.WorldToScreenPoint(boundPoint5);
        screenPoints[5] = camera.WorldToScreenPoint(boundPoint6);
        screenPoints[6] = camera.WorldToScreenPoint(boundPoint7);
        screenPoints[7] = camera.WorldToScreenPoint(boundPoint8);

        Vector2 topLeftPosition = Vector2.zero;
        Vector2 topRightPosition = Vector2.zero;
        Vector2 bottomLeftPosition = Vector2.zero;
        Vector2 bottomRightPosition = Vector2.zero;

        for (int a = 0; a < screenPoints.Length; a++)
        {
            //Top Left
            if (topLeftPosition.x == 0 || topLeftPosition.x > screenPoints[a].x)
            {
                topLeftPosition.x = screenPoints[a].x;
            }
            if (topLeftPosition.y == 0 || topLeftPosition.y > Screen.height - screenPoints[a].y)
            {
                topLeftPosition.y = Screen.height - screenPoints[a].y;
            }
            //Top Right
            if (topRightPosition.x == 0 || topRightPosition.x < screenPoints[a].x)
            {
                topRightPosition.x = screenPoints[a].x;
            }
            if (topRightPosition.y == 0 || topRightPosition.y > Screen.height - screenPoints[a].y)
            {
                topRightPosition.y = Screen.height - screenPoints[a].y;
            }
            //Bottom Left
            if (bottomLeftPosition.x == 0 || bottomLeftPosition.x > screenPoints[a].x)
            {
                bottomLeftPosition.x = screenPoints[a].x;
            }
            if (bottomLeftPosition.y == 0 || bottomLeftPosition.y < Screen.height - screenPoints[a].y)
            {
                bottomLeftPosition.y = Screen.height - screenPoints[a].y;
            }
            //Bottom Right
            if (bottomRightPosition.x == 0 || bottomRightPosition.x < screenPoints[a].x)
            {
                bottomRightPosition.x = screenPoints[a].x;
            }
            if (bottomRightPosition.y == 0 || bottomRightPosition.y < Screen.height - screenPoints[a].y)
            {
                bottomRightPosition.y = Screen.height - screenPoints[a].y;
            }
        }

        GUI.DrawTexture(new Rect(topLeftPosition.x - 16, topLeftPosition.y - 16, 16, 16), topLeftBorder);
        GUI.DrawTexture(new Rect(topRightPosition.x, topRightPosition.y - 16, 16, 16), topRightBorder);
        GUI.DrawTexture(new Rect(bottomLeftPosition.x - 16, bottomLeftPosition.y, 16, 16), bottomLeftBorder);
        GUI.DrawTexture(new Rect(bottomRightPosition.x, bottomRightPosition.y, 16, 16), bottomRightBorder);
    }
}

Étape 2: Configurer la sélection RTS

Créez un nouvel objet de jeu et appelez-le "_SelectionManager"
Attachez le script SC_SelectionManager à l'objet "_SelectionManager"
Attribuez les textures ci-dessous aux variables de bordure:

Faites glisser et déposez les objets que vous souhaitez sélectionner sur la scène (dans mon cas, j'ai utilisé les modèles du pack RPG/FPS Game Assets for PC/Mobile Industrial Set v2.0 du Asset Store)

Attachez le script SC_Selectable à chaque modèle
Attribuez un moteur de rendu de maillage (ou des moteurs de rendu de maillage s'il y a plusieurs objets) au tableau de rendus, cela est nécessaire pour calculer les limites de l'objet.

Appuyez maintenant sur Play et maintenez le bouton de la souris enfoncé pour commencer la sélection.

Passez la souris sur les Objets sélectionnables pour les sélectionner.

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