예제 #1
0
파일: arbiter.go 프로젝트: vova616/mater
func (arb *Arbiter) preStep(inv_dt float64) {
	const allowedPenetration = 0.01
	biasFactor := 0.0
	if Settings.PositionCorrection {
		biasFactor = 0.2
	}

	b1 := arb.ShapeA.Body
	b2 := arb.ShapeB.Body

	for i := 0; i < arb.NumContacts; i++ {
		c := &arb.Contacts[i]

		c.R1 = vect.Sub(c.Position, b1.Transform.Position)
		c.R2 = vect.Sub(c.Position, b2.Transform.Position)
		r1 := c.R1
		r2 := c.R2

		//Precompute normal mass, tangent mass, and bias
		rn1 := vect.Dot(r1, c.Normal)
		rn2 := vect.Dot(r2, c.Normal)
		kNormal := b1.invMass + b2.invMass
		kNormal += b1.invI*(vect.Dot(r1, r1)-rn1*rn1) +
			b2.invI*(vect.Dot(r2, r2)-rn2*rn2)
		c.MassNormal = 1.0 / kNormal

		tangent := vect.CrossVF(c.Normal, 1.0)
		rt1 := vect.Dot(r1, tangent)
		rt2 := vect.Dot(r2, tangent)
		kTangent := b1.invMass + b2.invMass
		kTangent += b1.invI*(vect.Dot(r1, r1)-rt1*rt1) +
			b2.invI*(vect.Dot(r2, r2)-rt2*rt2)
		c.MassTangent = 1.0 / kTangent

		c.Bias = -biasFactor * inv_dt * math.Min(0.0, c.Separation+allowedPenetration)

		if Settings.AccumulateImpulses {
			//Apply normal + friction impulse
			P := vect.Add(vect.Mult(c.Normal, c.Pn), vect.Mult(tangent, c.Pt))

			b1.Velocity.Sub(vect.Mult(P, b1.invMass))
			b1.AngularVelocity -= b1.invI * vect.Cross(r1, P)

			b2.Velocity.Add(vect.Mult(P, b2.invMass))
			b2.AngularVelocity += b2.invI * vect.Cross(r2, P)
		}

	}
}
예제 #2
0
파일: collide.go 프로젝트: vova616/mater
func findPoinsBehindSeg(contacts *[MaxPoints]Contact, num *int, seg *SegmentShape, poly *PolygonShape, pDist, coef float64) {
	dta := vect.Cross(seg.Tn, seg.Ta)
	dtb := vect.Cross(seg.Tn, seg.Tb)
	n := vect.Mult(seg.Tn, coef)

	for i := 0; i < poly.NumVerts; i++ {
		v := poly.TVerts[i]
		if vect.Dot(v, n) < vect.Dot(seg.Tn, seg.Ta)*coef+seg.Radius {
			dt := vect.Cross(seg.Tn, v)
			if dta >= dt && dt >= dtb {
				nextContact(contacts, num).reset(v, n, pDist)
			}
		}
	}
}
예제 #3
0
파일: collide.go 프로젝트: vova616/mater
func circle2segmentFunc(contacts *[MaxPoints]Contact, circle *CircleShape, segment *SegmentShape) int {
	rsum := circle.Radius + segment.Radius

	//Calculate normal distance from segment
	dn := vect.Dot(segment.Tn, circle.Tc) - vect.Dot(segment.Ta, segment.Tn)
	dist := math.Abs(dn) - rsum
	if dist > 0.0 {
		return 0
	}

	//Calculate tangential distance along segment
	dt := -vect.Cross(segment.Tn, circle.Tc)
	dtMin := -vect.Cross(segment.Tn, segment.Ta)
	dtMax := -vect.Cross(segment.Tn, segment.Tb)

	// Decision tree to decide which feature of the segment to collide with.
	if dt < dtMin {
		if dt < (dtMin - rsum) {
			return 0
		} else {
			return segmentEncapQuery(circle.Tc, segment.Ta, circle.Radius, segment.Radius, &contacts[0], segment.A_tangent)
		}
	} else {
		if dt < dtMax {
			n := segment.Tn
			if dn >= 0.0 {
				n.Mult(-1)
			}
			con := &contacts[0]
			pos := vect.Add(circle.Tc, vect.Mult(n, circle.Radius+dist*0.5))
			con.reset(pos, n, dist)
			return 1
		} else {
			if dt < (dtMax + rsum) {
				return segmentEncapQuery(circle.Tc, segment.Tb, circle.Radius, segment.Radius, &contacts[0], segment.B_tangent)
			} else {
				return 0
			}
		}
	}
	panic("Never reached")
}
예제 #4
0
파일: vertices.go 프로젝트: vova616/mater
// Checks if verts forms a valid polygon.
// The vertices must be convex and winded clockwise.
func (verts Vertices) ValidatePolygon() bool {
	numVerts := len(verts)
	for i := 0; i < numVerts; i++ {
		a := verts[i]
		b := verts[(i+1)%numVerts]
		c := verts[(i+2)%numVerts]

		if vect.Cross(vect.Sub(b, a), vect.Sub(c, b)) > 0.0 {
			return false
		}
	}

	return true
}
예제 #5
0
파일: collide.go 프로젝트: vova616/mater
func circle2polyFunc(contacts *[MaxPoints]Contact, circle *CircleShape, poly *PolygonShape) int {

	axes := poly.TAxes

	mini := 0
	min := vect.Dot(axes[0].N, circle.Tc) - axes[0].D - circle.Radius
	for i, axis := range axes {
		dist := vect.Dot(axis.N, circle.Tc) - axis.D - circle.Radius
		if dist > 0.0 {
			return 0
		} else if dist > min {
			min = dist
			mini = i
		}
	}

	n := axes[mini].N
	a := poly.TVerts[mini]
	b := poly.TVerts[(mini+1)%poly.NumVerts]
	dta := vect.Cross(n, a)
	dtb := vect.Cross(n, b)
	dt := vect.Cross(n, circle.Tc)

	if dt < dtb {
		return circle2circleQuery(circle.Tc, b, circle.Radius, 0.0, &contacts[0])
	} else if dt < dta {
		contacts[0].reset(
			vect.Sub(circle.Tc, vect.Mult(n, circle.Radius+min/2.0)),
			vect.Mult(n, -1),
			min,
		)
		return 1
	} else {
		return circle2circleQuery(circle.Tc, a, circle.Radius, 0.0, &contacts[0])
	}
	panic("Never reached")
}
예제 #6
0
파일: arbiter.go 프로젝트: vova616/mater
func (arb *Arbiter) applyImpulse() {
	sA := arb.ShapeA
	sB := arb.ShapeB

	b1 := sA.Body
	b2 := sB.Body

	//xfA := b1.Transform
	//xfB := b2.Transform

	for i := 0; i < arb.NumContacts; i++ {
		c := &arb.Contacts[i]

		// Relative velocity at contact
		dv := vect.Vect{}
		{
			t1 := vect.Add(b2.Velocity, vect.CrossFV(b2.AngularVelocity, c.R2))
			t2 := vect.Sub(b1.Velocity, vect.CrossFV(b1.AngularVelocity, c.R1))

			dv = vect.Sub(t1, t2)
		}

		// Compute normal impulse
		vn := vect.Dot(dv, c.Normal)

		dPn := c.MassNormal * (-vn + c.Bias)

		if Settings.AccumulateImpulses {
			// Clamp the accumulated impulse
			Pn0 := c.Pn
			c.Pn = math.Max(Pn0+dPn, 0.0)
			dPn = c.Pn - Pn0
		} else {
			dPn = math.Max(dPn, 0.0)
		}

		//Apply contact impulse
		Pn := vect.Mult(c.Normal, dPn)

		b1.Velocity.Sub(vect.Mult(Pn, b1.invMass))
		b1.AngularVelocity -= b1.invI * vect.Cross(c.R1, Pn)

		b2.Velocity.Add(vect.Mult(Pn, b2.invMass))
		b2.AngularVelocity += b2.invI * vect.Cross(c.R2, Pn)

		//Relative velocity at contact
		{
			t1 := vect.Add(b2.Velocity, vect.CrossFV(b2.AngularVelocity, c.R2))
			t2 := vect.Sub(b1.Velocity, vect.CrossFV(b1.AngularVelocity, c.R1))

			dv = vect.Sub(t1, t2)
		}

		tangent := vect.CrossVF(c.Normal, 1.0)
		vt := vect.Dot(dv, tangent)
		dPt := c.MassTangent * (-vt)

		if Settings.AccumulateImpulses {
			//Compute friction impulse
			maxPt := arb.Friction * c.Pn

			//Clamp Friction
			oldTangentImpulse := c.Pt
			c.Pt = clamp(oldTangentImpulse+dPt, -maxPt, maxPt)
			dPt = c.Pt - oldTangentImpulse
		} else {
			maxPt := arb.Friction * dPn
			dPt = clamp(dPt, -maxPt, maxPt)
		}

		// Apply contact impulse
		Pt := vect.Mult(tangent, dPt)

		b1.Velocity.Sub(vect.Mult(Pt, b1.invMass))
		b1.AngularVelocity -= b1.invI * vect.Cross(c.R1, Pt)

		b2.Velocity.Add(vect.Mult(Pt, b2.invMass))
		b2.AngularVelocity += b2.invI * vect.Cross(c.R2, Pt)
	}
}