Add: anchored objects

Anchored objects can be connected together by calling a method.

Assets/Scripts/Anchor.meta

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+fileFormatVersion: 2
+guid: 60cc4243135e5cd4b9d21f837db97b31
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/Scripts/Anchor/Anchor.cs

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+using UnityEngine;
+#if UNITY_EDITOR
+using UnityEditor;
+#endif
+
+public class Anchor : MonoBehaviour
+{
+    // Comparison tolerances
+    const float positionEPS = 0.1f;
+    const float rotationEPS = 0.1f;
+
+    // See anchor within editor
+    #if UNITY_EDITOR
+    public const float tipsSize = 0.2f;
+
+    private void OnDrawGizmosSelected()
+    {
+        Handles.color = Color.magenta;
+        Vector3 position = transform.position;
+        float size = transform.lossyScale.x;
+
+        if (size >= 0)
+        {
+            Handles.ArrowHandleCap(
+                0,
+                position,
+                Quaternion.LookRotation(transform.forward),
+                size,
+                EventType.Repaint
+            );
+
+            Vector3 leftLimit = position - size*transform.right;
+            Vector3 rightLimit = position + size*transform.right;
+            Handles.DrawLine(leftLimit, rightLimit);
+
+            Handles.DrawLine(
+                leftLimit - tipsSize*size*transform.forward,
+                leftLimit + tipsSize*size*transform.forward
+            );
+            Handles.DrawLine(
+                rightLimit - tipsSize*size*transform.forward,
+                rightLimit + tipsSize*size*transform.forward
+            );
+        }
+    }
+    #endif
+
+    /// <summary>
+    /// Test whether this anchor is connected to another anchor
+    /// </summary>
+    /// <param name="other">The other anchor to compare to</param>
+    /// <param name="matchScales">Whether to test for scale match</param>
+    /// <returns>The anchoring state of this anchor and the given anchor</returns>
+    public bool IsAnchoredTo(Anchor other, bool matchScales=true)
+    {
+        if (matchScales && (Mathf.Abs(transform.lossyScale.x - other.transform.lossyScale.x) > positionEPS))
+        {
+            return false;
+        }
+        return Quaternion.Angle(transform.rotation*Quaternion.AngleAxis(180f, Vector3.up), other.transform.rotation) < rotationEPS
+            && Vector3.Distance(transform.position, other.transform.position) < positionEPS;
+    }
+}

Assets/Scripts/Anchor/Anchor.cs.meta

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+fileFormatVersion: 2
+guid: c8e92a0688e18aa4891eb7937ca9cd0e

Assets/Scripts/Anchor/AnchoredObject.cs

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+using System.Collections.Generic;
+using UnityEngine;
+
+public class AnchoredObject : MonoBehaviour
+{
+    [SerializeField] List<Anchor> anchors = new List<Anchor>();
+
+    /// <summary>
+    /// Get an anchor from its ID (index)
+    /// </summary>
+    /// <param name="anchorID">ID of the anchor to search for</param>
+    /// <returns>The anchor that has the given ID</returns>
+    public Anchor GetAnchorFromID(int anchorID)
+    {
+        if (anchorID > anchors.Count)
+        {
+            Debug.LogError("Error: Tried to anchor to an inexisting anchor. Check anchors list.");
+        }
+        return anchors[anchorID];
+    }
+
+    /// <summary>
+    /// Anchor this object to another
+    /// </summary>
+    /// <param name="partner">The anchored object to connect to</param>
+    /// <param name="partnerAnchorID">ID of the partner anchor to connect to</param>
+    /// <param name="myAnchorID">ID of anchor this object wants to connect</param>
+    /// <param name="matchScales">Whether to anchor scales too</param>
+    public void AnchorTo(AnchoredObject partner, int partnerAnchorID, int myAnchorID, bool matchScales=true)
+    {
+        AnchorTo(
+            GetAnchorFromID(myAnchorID),
+            partner.GetAnchorFromID(partnerAnchorID)
+        );
+    }
+
+    /// <summary>
+    /// Anchor this object to another
+    /// </summary>
+    /// <param name="myAnchor">The anchor to connect</param>
+    /// <param name="partnerAnchor">The anchor of the other object to connect to</param>
+    /// <param name="matchScales">Whether to anchor scales too</param>
+    public void AnchorTo(Anchor myAnchor, Anchor partnerAnchor, bool matchScales=true)
+    {
+        if (matchScales)
+        {
+            // Match scales
+            float sizeDelta = partnerAnchor.transform.lossyScale.x / myAnchor.transform.lossyScale.x;
+            transform.localScale *= sizeDelta;
+        }
+
+        // Match rotations
+        transform.rotation =
+            partnerAnchor.transform.rotation
+            * Quaternion.AngleAxis(180f, Vector3.up)
+            * Quaternion.Inverse(myAnchor.transform.rotation)
+            * transform.rotation;
+
+        // Match positions
+        transform.position += partnerAnchor.transform.position - myAnchor.transform.position;
+    }
+
+    /// <summary>
+    /// Connect multiple anchors of this object with multiple anchors.
+    /// If one of the connections fails, the anchoring operation fails.
+    /// </summary>
+    /// <param name="partner">The anchored object to connect to</param>
+    /// <param name="partnerAnchorIDs">IDs of the partner anchors to connect to</param>
+    /// <param name="myAnchorIDs">IDs of the anchors this object wants to connect</param>
+    /// <param name="matchScales">Whether to anchor scales too</param>
+    /// <returns>Whether the anchoring succeeded or not</returns>
+    public bool AnchorToMultiple(AnchoredObject partner, IList<int> partnerAnchorIDs, IList<int> myAnchorIDs, bool matchScales=true)
+    {
+        if (myAnchorIDs.Count != partnerAnchorIDs.Count)
+        {
+            Debug.LogError("Error: Number of anchors must match.");
+        }
+        List<Anchor> myAnchors = new List<Anchor>();
+        List<Anchor> partnerAnchors = new List<Anchor>();
+        for (int i = 0; i < myAnchorIDs.Count; i++)
+        {
+            myAnchors.Add(GetAnchorFromID(myAnchorIDs[i]));
+            partnerAnchors.Add(partner.GetAnchorFromID(partnerAnchorIDs[i]));
+        }
+        return AnchorToMultiple(myAnchors, partnerAnchors, matchScales);
+    }
+
+    /// <summary>
+    /// Connect multiple anchors of this object with multiple anchors.
+    /// If one of the connections fails, the anchoring operation fails.
+    /// </summary>
+    /// <param name="myAnchors">The anchors this object wants to connect</param>
+    /// <param name="targetAnchors">The anchors this object wants to connect to</param>
+    /// <param name="matchScales">Whether to anchor scales too</param>
+    /// <returns>Whether the anchoring succeeded or not</returns>
+    public bool AnchorToMultiple(IList<Anchor> myAnchors, IList<Anchor> targetAnchors, bool matchScales=true)
+    {
+        if (myAnchors.Count != targetAnchors.Count)
+        {
+            Debug.LogError("Error: Number of anchors must match.");
+            return false;
+        }
+        if (myAnchors.Count == 0)
+        {
+            Debug.LogError("Amount of anchors to connect must be at least 1.");
+            return false;
+        }
+
+        // Connect the first anchors. Then, test if other anchors match.
+        AnchorTo(myAnchors[0], targetAnchors[0], matchScales);
+        for (int i=1; i<myAnchors.Count; i++)
+        {
+            if (! myAnchors[i].IsAnchoredTo(targetAnchors[i], matchScales))
+            {
+                return false;
+            }
+        }
+        return true;
+    }
+}

Assets/Scripts/Anchor/AnchoredObject.cs.meta

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+fileFormatVersion: 2
+guid: a7e5718d381203c488586d59acd4a86d