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/*
* Simple Mechanics Simulator (SiMS)
* copyright (c) 2009 Jakob Odersky
* made available under the MIT License
*/
package sims.dynamics.joints
import sims.geometry._
/**Eine Hooksche Feder.
* @param node1 erster Koerper der Verbindung
* @param anchor1 Bindungspunkt auf Koerper eins
* @param node2 zweiter Koerper der Verbindung
* @param anchor2 Bindungspunkt auf Koerper zwei
* @param springConstant Federkonstante
* @param initialLength Initiallaenge
*/
case class SpringJoint(node1: Body, anchor1: Vector2D, node2: Body, anchor2: Vector2D, springConstant: Double, initialLength: Double) extends Joint with ForceJoint{
def this(node1: Body, anchor1: Vector2D, node2: Body, anchor2: Vector2D, springConstant: Double) = {
this(node1: Body, anchor1, node2: Body, anchor2, springConstant: Double, (anchor2 - anchor1).length)
}
def this(node1: Body, node2: Body, springConstant: Double, initialLength: Double) = {
this(node1: Body, node1.pos, node2: Body, node2.pos, springConstant: Double, initialLength: Double)
}
def this(node1: Body, node2: Body, springConstant: Double) = {
this(node1: Body, node1.pos, node2: Body, node2.pos, springConstant: Double, (node2.pos - node1.pos).length)
}
private val a1 = anchor1 - node1.pos
private val a2 = anchor2 - node2.pos
private val initRotation1 = node1.rotation
private val initRotation2 = node2.rotation
/**Ergibt den Bindungspunkt auf Koerper eins.*/
def connection1 = (a1 rotate (node1.rotation - initRotation1)) + node1.pos
/**Ergibt den Bindungspunkt auf Koerper zwei.*/
def connection2 = (a2 rotate (node2.rotation - initRotation2)) + node2.pos
/**Daempfung.*/
var damping = 0.0
/**Relative Position der Bindungspunkte.*/
def x = connection2 - connection1
/**Relative Geschwindigkeit der Bindungspunkte.*/
def v = node2.velocityOfPoint(connection2) - node1.velocityOfPoint(connection1)
/**Ergibt die Federkraft nach dem Hookschen Gesetz.*/
def force = (x.length - initialLength) * springConstant
/**Uebt die Federkraft auf die Bindungspunkte aus.*/
def applyForce() = {
node1.applyForce(x.unit * force - (v * damping) project x, connection1)
node2.applyForce(-x.unit * force - (v * damping) project x, connection2)
//println("this should not happen")
}
def correctVelocity(h: Double) = {
/*
val x = this.x //relativer Abstand
val v = this.v //relative Geschwindigkeit
val r1 = (connection1 - node1.pos) //Abstand Punkt-Schwerpunkt, Koerper 1
val r2 = (connection2 - node2.pos) //Abstand Punkt-Schwerpunkt, Koerper 2
val cr1 = r1 cross x.unit //Kreuzprodukt
val cr2 = r2 cross x.unit //Kreuzprodukt
val Cdot = x.unit dot v //Velocity-Constraint
val invMass = 1/node1.mass + 1/node1.I * cr1 * cr1 + 1/node2.mass + 1/node2.I * cr2 * cr2 //=J M^-1 JT
val m = if (invMass == 0.0) 0.0 else 1/invMass //Test um Nulldivision zu vermeiden
val lambda = Math.min(Math.max(-this.force * h, (-m * Cdot)), this.force * h)
println (force * h, -m * Cdot)
val impulse = x.unit * lambda
node1.applyImpulse(-impulse, connection1)
node2.applyImpulse(impulse, connection2)
*/
}
def correctPosition(h: Double) = {
}
}
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