// Calculates the transformed vertices and axes and the bounding box.
func (poly *PolygonShape) update(xf transform.Transform) AABB {
//transform axes
{
src := poly.Axes
dst := poly.TAxes
for i := 0; i < poly.NumVerts; i++ {
n := xf.RotateVect(src[i].N)
dst[i].N = n
dst[i].D = vect.Dot(xf.Position, n) + src[i].D
}
/*
fmt.Println("")
fmt.Println("Started Axes")
fmt.Println(xf.Rotation, xf.Position)
for i:=0;i<poly.NumVerts;i++ {
fmt.Println(src[i], dst[i])
}
*/
}
//transform verts
{
inf := vect.Float(math.Inf(1))
aabb := AABB{
Lower: vect.Vect{inf, inf},
Upper: vect.Vect{-inf, -inf},
}
src := poly.Verts
dst := poly.TVerts
for i := 0; i < poly.NumVerts; i++ {
v := xf.TransformVect(src[i])
dst[i] = v
aabb.Lower.X = vect.FMin(aabb.Lower.X, v.X)
aabb.Upper.X = vect.FMax(aabb.Upper.X, v.X)
aabb.Lower.Y = vect.FMin(aabb.Lower.Y, v.Y)
aabb.Upper.Y = vect.FMax(aabb.Upper.Y, v.Y)
}
/*
fmt.Println("Verts")
for i:=0;i<poly.NumVerts;i++ {
fmt.Println(src[i], dst[i])
}
*/
return aabb
}
}
func (arb *Arbiter) preStep2(inv_dt, slop, bias vect.Float) {
a := arb.ShapeA.Body
b := arb.ShapeB.Body
for i := 0; i < arb.NumContacts; i++ {
con := arb.Contacts[i]
// Calculate the offsets.
con.r1 = vect.Sub(con.p, a.p)
con.r2 = vect.Sub(con.p, b.p)
//con.Normal = vect.Vect{-1,0}
// Calculate the mass normal and mass tangent.
con.nMass = 1.0 / k_scalar(a, b, con.r1, con.r2, con.n)
con.tMass = 1.0 / k_scalar(a, b, con.r1, con.r2, vect.Perp(con.n))
// Calculate the target bias velocity.
con.bias = -bias * inv_dt * vect.FMin(0.0, con.dist+slop)
con.jBias = 0.0
//con.jtAcc = 0
//con.jnAcc = 0
//fmt.Println("con.dist", con.dist)
// Calculate the target bounce velocity.
con.bounce = normal_relative_velocity(a, b, con.r1, con.r2, con.n) * arb.e
}
}
func (poly *PolygonShape) ValueOnAxis(n vect.Vect, d vect.Float) vect.Float {
verts := poly.TVerts
min := vect.Dot(n, verts[0])
for i := 1; i < poly.NumVerts; i++ {
min = vect.FMin(min, vect.Dot(n, verts[i]))
}
return min - d
}
func (tree *BBTree) GetBB(obj Indexable) AABB {
v, ok := obj.Velocity()
if ok {
bb := obj.AABB()
coef := vect.Float(0.1)
l := bb.Lower.X
b := bb.Lower.Y
r := bb.Upper.X
t := bb.Upper.Y
x := (r - l) * coef
y := (t - b) * coef
v = vect.Mult(v, 0.1)
return NewAABB(l+vect.FMin(-x, v.X), b+vect.FMin(-y, v.Y), r+vect.FMax(x, v.X), t+vect.FMax(y, v.Y))
}
return obj.AABB()
}
func segValueOnAxis(seg *SegmentShape, n vect.Vect, d vect.Float) vect.Float {
a := vect.Dot(n, seg.Ta) - seg.Radius
b := vect.Dot(n, seg.Tb) - seg.Radius
return vect.FMin(a, b) - d
}
func MergedAreaPtr(a, b *AABB) vect.Float {
return (vect.FMax(a.Upper.X, b.Upper.X) - vect.FMin(a.Lower.X, b.Lower.X)) * (vect.FMax(a.Upper.Y, b.Upper.Y) - vect.FMin(a.Lower.Y, b.Lower.Y))
}