Example #1
0
//Called to update N, Tn, Ta, Tb and the the bounding box.
func (segment *SegmentShape) update(xf transform.Transform) AABB {
	a := xf.TransformVect(segment.A)
	b := xf.TransformVect(segment.B)
	segment.Ta = a
	segment.Tb = b
	segment.N = vect.Perp(vect.Normalize(vect.Sub(segment.B, segment.A)))
	segment.Tn = xf.RotateVect(segment.N)

	rv := vect.Vect{segment.Radius, segment.Radius}

	min := vect.Min(a, b)
	min.Sub(rv)

	max := vect.Max(a, b)
	max.Add(rv)

	return AABB{
		min,
		max,
	}
}
Example #2
0
// Sets the vertices offset by the offset and calculates the PolygonAxes.
func (poly *PolygonShape) SetVerts(verts Vertices, offset vect.Vect) {

	if verts == nil {
		log.Printf("Error: no vertices passed!")
		return
	}

	if verts.ValidatePolygon() == false {
		log.Printf("Warning: vertices not valid")
	}

	numVerts := len(verts)
	oldnumVerts := len(poly.Verts)
	poly.NumVerts = numVerts

	if oldnumVerts < numVerts {
		//create new slices
		poly.Verts = make(Vertices, numVerts)
		poly.TVerts = make(Vertices, numVerts)
		poly.Axes = make([]PolygonAxis, numVerts)
		poly.TAxes = make([]PolygonAxis, numVerts)

	} else {
		//reuse old slices
		poly.Verts = poly.Verts[:numVerts]
		poly.TVerts = poly.TVerts[:numVerts]
		poly.Axes = poly.Axes[:numVerts]
		poly.TAxes = poly.TAxes[:numVerts]
	}

	for i := 0; i < numVerts; i++ {
		a := vect.Add(offset, verts[i])
		b := vect.Add(offset, verts[(i+1)%numVerts])
		n := vect.Normalize(vect.Perp(vect.Sub(b, a)))

		poly.Verts[i] = a
		poly.Axes[i].N = n
		poly.Axes[i].D = vect.Dot(n, a)
	}
}