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Diffstat (limited to 'src/main/scala/sims/dynamics/RevoluteJoint.scala')
| -rw-r--r-- | src/main/scala/sims/dynamics/RevoluteJoint.scala | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/src/main/scala/sims/dynamics/RevoluteJoint.scala b/src/main/scala/sims/dynamics/RevoluteJoint.scala new file mode 100644 index 0000000..5d7a85f --- /dev/null +++ b/src/main/scala/sims/dynamics/RevoluteJoint.scala @@ -0,0 +1,55 @@ +/* _____ _ __ ________ ___ *\ +** / ___/(_) |/ / ___/ |__ \ Simple Mechanics Simulator 2 ** +** \__ \/ / /|_/ /\__ \ __/ / copyright (c) 2011 Jakob Odersky ** +** ___/ / / / / /___/ / / __/ ** +** /____/_/_/ /_//____/ /____/ ** +\* */ + +package sims.dynamics + +import sims.dynamics.constraints._ +import sims.math._ + +/** A revolute joint, used to keep two bodies fixed relatively at one point. + * + * This joint removes two degrees of freedom between two bodies, + * hence it contains two [[sims.dynamics.constraints.Constraint]]s. + * + * @param body1 first body connected by this joint + * @param body2 second body connected by this joint + * @param anchor anchor point where bodies are fixed relatively */ +class RevoluteJoint(val body1: Body, val body2: Body, val anchor: Vector2D) extends Joint { + def this(body1: Body, body2: Body) = this(body1, body2, body1.position) + + private val self = this + + private val local1 = anchor - body1.position + private val local2 = anchor - body2.position + + private val rotation01 = body1.rotation + private val rotation02 = body2.rotation + + def r1 = (local1 rotate (body1.rotation - rotation01)) + def r2 = (local2 rotate (body2.rotation - rotation02)) + + def x1 = body1.position + r1 + def x2 = body2.position + r2 + + def x = x2 - x1 + + val constraints = List( + new Constraint { + val body1 = self.body1 + val body2 = self.body2 + def value = x.x + def jacobian = new Jacobian(-Vector2D(1, 0), r1.y, Vector2D(1, 0), -r2.y) + }, + new Constraint { + val body1 = self.body1 + val body2 = self.body2 + def value = x.y + def jacobian = new Jacobian(-Vector2D(0, 1), -r1.x, Vector2D(0, 1), r2.x) + } + ) + +}
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