From cd25f31a7791e36a3604460904e727a20151192f Mon Sep 17 00:00:00 2001
From: Felix Klenner <felix@zuim.de>
Date: Fri, 1 Dec 2023 18:18:34 +0100
Subject: [PATCH] automatically find starting points of cables

---
 Assets/CableJointsAlgorithm.cs |  6 +++---
 Assets/Controller.cs           | 22 +++++++++++++---------
 Assets/RollerProperties.cs     |  2 +-
 3 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/Assets/CableJointsAlgorithm.cs b/Assets/CableJointsAlgorithm.cs
index c85961e..f3953fb 100644
--- a/Assets/CableJointsAlgorithm.cs
+++ b/Assets/CableJointsAlgorithm.cs
@@ -5,13 +5,13 @@ using static System.Math;
 
 /** Cable Joints algorithm based on Paper by Matthias Müller, Nuttapong Chentanez, Stefan Jeschke and Miles Macklin*/
 public static class CableJointsAlgorithm {
-    public static void TimeStep(List<Cable> cables) {
+    public static void TimeStep(List<GameObject> cableStartingPoints) {
         //handle each cable individually
-        foreach (var cable in cables) {
+        foreach (var cable in cableStartingPoints) {
             float totalDist = 0;
             
             //calculate new attachment points for all joints
-            for (var go = cable.firstRoller; go != null; go = go.GetComponent<RollerProperties>().linkTo) {
+            for (var go = cable; go != null; go = go.GetComponent<RollerProperties>().linkTo) {
                 if (go.GetComponent<RollerProperties>().linkTo != null) {
                     var dist = go.GetComponent<DistanceJoint2D>();
                     var rp = go.GetComponent<RollerProperties>();
diff --git a/Assets/Controller.cs b/Assets/Controller.cs
index b61650f..ab5cdcc 100644
--- a/Assets/Controller.cs
+++ b/Assets/Controller.cs
@@ -3,7 +3,7 @@ using TMPro;
 using UnityEngine;
 
 public class Controller : MonoBehaviour {
-    private List<Cable> cables = new();
+    private List<GameObject> cableStartingPoints = new();
 
     //Initialize
     void Awake() {
@@ -36,7 +36,13 @@ public class Controller : MonoBehaviour {
 
                 //collisions and physics
                 Rigidbody2D rb = go.GetOrAddComponent<Rigidbody2D>();
-                rb.useAutoMass = true; // mass is based on size
+                // mass is based on area, if not provided
+                if (rp.mass == null) {
+                    rb.useAutoMass = rp.mass == null;
+                }
+                else {
+                    rb.mass = rp.mass.Value;
+                }
                 rb.angularDrag = 1;
                 rb.drag = 1;
                 if (rp.movement == RollerProperties.RotationType.Fixed) {
@@ -45,8 +51,10 @@ public class Controller : MonoBehaviour {
 
                 go.AddComponent<PolygonCollider2D>();
 
-                if (rp.start) {
-                    cables.Add(new Cable { firstRoller = go });
+                //build list of cable starting objects 
+                cableStartingPoints.Add(go);
+                if (rp.linkTo != null) {
+                    cableStartingPoints.Remove(rp.linkTo);
                 }
 
                 Debug.Log("Initialized roller: " + go.name);
@@ -129,12 +137,8 @@ public class Controller : MonoBehaviour {
         }
         
         if (waitedFrames++ > -1) {
-            CableJointsAlgorithm.TimeStep(cables);
+            CableJointsAlgorithm.TimeStep(cableStartingPoints);
             waitedFrames = 0;
         }
     }
-}
-
-public class Cable {
-    public GameObject firstRoller;
 }
\ No newline at end of file
diff --git a/Assets/RollerProperties.cs b/Assets/RollerProperties.cs
index 2317304..6655884 100644
--- a/Assets/RollerProperties.cs
+++ b/Assets/RollerProperties.cs
@@ -5,12 +5,12 @@ using UnityEngine.Serialization;
 [System.Serializable]
 public class RollerProperties : MonoBehaviour {
     //settings
-    [SerializeField] public bool start = false;
     [SerializeField] public bool clockwise = false;
     [SerializeField] public GameObject linkTo = null;
     [SerializeField] public RotationType movement = RotationType.Fixed;
     [FormerlySerializedAs("fixedAttachmentPoint")] [SerializeField] public bool useFixedAttachmentPoint = false;
     [SerializeField] public Vector2 attachmentPoint = new Vector2(0, 0);
+    [SerializeField] public float? mass = null;
 
     //references
     protected internal GameObject text;