View source for 3D Physics Based Rope

== Rope_Line.js ==
<syntaxhighlight lang="javascript">
//============================
//==	Physics Based 3D Rope ==
//==	File: Rope_Tube.js	==
//==	By: Jacob Fletcher	==
//==	Use and alter Freely	==
//============================
//To see other things I have created, visit me at www.reverieinterative.com
//How To Use:
// ( BASIC )
// 1. Simply add this script to the object you want a rope teathered to
// 3. Assign the other end of the rope as the "Target" object in this script
// 4. Play and enjoy!
// (About Character Joints)
// Sometimes your rope needs to be very limp and by that I mean NO SPRINGY EFFECT.
// In order to do this, you must loosen it up using the swingAxis and twist limits.
// For example, On my joints in my drawing app, I set the swingAxis to (0,0,1) sense
// the only axis I want to swing is the Z axis (facing the camera) and the other settings to around -100 or 100.
var target : Transform;
var material : Material;
var ropeWidth = 0.5;
var resolution = 0.5;
var ropeDrag = 0.1;
var ropeMass = 0.5;
var radialSegments = 6;
var startRestrained = true;
var endRestrained = false;
var useMeshCollision = false;
// Private Variables (Only change if you know what your doing)
private var segmentPos : Vector3[];
private var joints : GameObject[];
private var tubeRenderer : GameObject;
private var line : TubeRenderer;
private var segments = 4;
private var rope = false;
//Joint Settings
var swingAxis = Vector3(0,1,0);
var lowTwistLimit = 0.0;
var highTwistLimit = 0.0;
var swing1Limit	= 20.0;
// Require a Rigidbody
@script RequireComponent(Rigidbody)
	
function OnDrawGizmos() {
	if(target) {
		Gizmos.color = Color.yellow;
		Gizmos.DrawLine (transform.position, target.position);
		Gizmos.DrawWireSphere ((transform.position+target.position)/2,ropeWidth);
		Gizmos.color = Color.green;
		Gizmos.DrawWireSphere (transform.position, ropeWidth);
		Gizmos.color = Color.red;
		Gizmos.DrawWireSphere (target.position, ropeWidth);
	} else {
		Gizmos.color = Color.green;
		Gizmos.DrawWireSphere (transform.position, ropeWidth);	
	}
}

function Awake()
{
	if(target) {
		 BuildRope();
	} else {
		Debug.LogError("You must have a gameobject attached to target: " + this.name,this);	
	}
}

function LateUpdate()
{
	if(target) {
		// Does rope exist? If so, update its position
		if(rope) {
		 line.SetPoints(segmentPos, ropeWidth, Color.white);
		 line.enabled = true;
			segmentPos[0] = transform.position;
			for(var s:int=1;s<segments;s++)
			{
			 segmentPos[s] = joints[s].transform.position;
			}
		}
	}
}

function BuildRope()
{
	tubeRenderer = new GameObject("TubeRenderer_" + gameObject.name);
	line = tubeRenderer.AddComponent(TubeRenderer);
	line.useMeshCollision = useMeshCollision;
	// Find the amount of segments based on the distance and resolution
	// Example: [resolution of 1.0 = 1 joint per unit of distance]
	segments = Vector3.Distance(transform.position,target.position)*resolution;
	if(material) {
		 material.SetTextureScale("_MainTex",Vector2(1,segments+2));
		 if(material.GetTexture("_BumpMap"))
			material.SetTextureScale("_BumpMap",Vector2(1,segments+2));
	}
	line.vertices = new TubeVertex[segments];
	line.crossSegments = radialSegments;
	line.material = material;
	segmentPos = new Vector3[segments];
	joints = new GameObject[segments];
	segmentPos[0] = transform.position;
	segmentPos[segments-1] = target.position;
	// Find the distance between each segment
	var segs = segments-1;
	var seperation = ((target.position - transform.position)/segs);
	for(var s:int=0;s < segments;s++)
	{
		// Find the each segments position using the slope from above
		var vector : Vector3 = (seperation*s) + transform.position;	
		segmentPos[s] = vector;
		//Add Physics to the segments
		AddJointPhysics(s);
	}
	// Attach the joints to the target object and parent it to this object
	var end : CharacterJoint = target.gameObject.AddComponent("CharacterJoint");
	end.connectedBody = joints[joints.length-1].transform.rigidbody;
	end.swingAxis = swingAxis;
	end.lowTwistLimit.limit = lowTwistLimit;
	end.highTwistLimit.limit = highTwistLimit;
	end.swing1Limit.limit	= swing1Limit;
	target.parent = transform;
	if(endRestrained)
	{
		end.rigidbody.isKinematic = true;
	}
	if(startRestrained)
	{
		transform.rigidbody.isKinematic = true;
	}
	// Rope = true, The rope now exists in the scene!
	rope = true;
}

function AddJointPhysics(n : int)
{
	joints[n] = new GameObject("Joint_" + n);
	joints[n].transform.parent = transform;
	var rigid : Rigidbody = joints[n].AddComponent("Rigidbody");
	if(!useMeshCollision) {
		 var col : SphereCollider = joints[n].AddComponent("SphereCollider");
		 col.radius = ropeWidth;
	}
	var ph : CharacterJoint = joints[n].AddComponent("CharacterJoint");
	ph.swingAxis = swingAxis;
	ph.lowTwistLimit.limit = lowTwistLimit;
	ph.highTwistLimit.limit = highTwistLimit;
	ph.swing1Limit.limit	= swing1Limit;
	//ph.breakForce = ropeBreakForce; <--------------- TODO
	joints[n].transform.position = segmentPos[n];
	rigid.drag = ropeDrag;
	rigid.mass = ropeMass;
	if(n==0){			ph.connectedBody = transform.rigidbody;
	} else
	{
		ph.connectedBody = joints[n-1].rigidbody;	
	}
} </syntaxhighlight>