1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
|
package sims.dynamics
import sims.collision.{Collision => CCollision}
import sims.dynamics.constraints._
import sims.math._
class RestingPoint(collision: CCollision[Shape], point: Vector2D) extends Constraint {
import collision._
val body1 = item1.body
val body2 = item2.body
def relativeVelocity = body2.velocityOfPoint(point) - body1.velocityOfPoint(point)
override def inequality = true
override val limit = Some((0.0, Double.PositiveInfinity))
override def value = -overlap
override def jacobian =
new Jacobian(-normal.unit, -((point - body1.position) cross normal.unit),
normal.unit, ((point - body2.position) cross normal.unit))
val slop = 0.005
override def error =
if (collision.overlap > slop)
-(collision.overlap - slop)
else 0.0
}
class ImpactPoint(collision: CCollision[Shape], point: Vector2D) extends Constraint {
import collision._
val body1 = item1.body
val body2 = item2.body
def relativeVelocity = body2.velocityOfPoint(point) - body1.velocityOfPoint(point)
override def inequality = true
override val limit = Some((0.0, Double.PositiveInfinity))
override def value = -overlap
override def jacobian =
new Jacobian(-normal.unit, -((point - body1.position) cross normal.unit),
normal.unit, ((point - body2.position) cross normal.unit))
val restitution = math.min(collision.item1.restitution, collision.item2.restitution)
override def bias = (relativeVelocity dot collision.normal.unit) * restitution
override def error = 0
}
object ContactResolver {
def relativeVelocity(collision: CCollision[Shape], point: Vector2D) =
collision.item2.body.velocityOfPoint(point) - collision.item2.body.velocityOfPoint(point)
def resolve(collision: CCollision[Shape]): Seq[Constraint] = for (p <- collision.points) yield {
val v = (relativeVelocity(collision, p) dot collision.normal.unit)
if (v < -1) new RestingPoint(collision, p)
else new ImpactPoint(collision, p)
}
}
|
