func vecInsideConvexPoly(v linear.Vec2, p linear.Poly) bool {
for i := range p {
seg := p.Seg(i)
if seg.Left(v) {
return false
}
}
return true
}
// ExistsClearLos checks that there is a clear LoS bettween two points and
// expands all polys in the room so that anything that might normally only clip
// on a vertex will be guaranteed to block LoS.
func (r *Room) ExistsClearLos(a, b linear.Vec2, epsilon float64) bool {
los := linear.Seg2{a, b}
var expandedPoly linear.Poly
for _, wall := range r.Walls {
expandPoly(wall, &expandedPoly)
for i := range expandedPoly {
seg := expandedPoly.Seg(i)
if seg.DoesIsect(los) {
return false
}
}
}
return true
}
func expandPoly(in linear.Poly, out *linear.Poly) {
if len(*out) < len(in) {
*out = make(linear.Poly, len(in))
}
for i := range *out {
(*out)[i] = linear.Vec2{}
}
for i, v := range in {
segi := in.Seg(i)
(*out)[i] = (*out)[i].Add(v.Add(segi.Ray().Cross().Norm().Scale(8.0)))
j := (i - 1 + len(in)) % len(in)
segj := in.Seg(j)
(*out)[i] = (*out)[i].Add(v.Add(segj.Ray().Cross().Norm().Scale(8.0)))
}
for i := range *out {
(*out)[i] = (*out)[i].Scale(0.5)
}
}
func PolySpec3(c gospec.Context) {
p := linear.Poly{
{0, 0},
{0, 1},
{1, 1},
{1, 0},
}
c.Specify("Check that Poly.Seg(i) returns the i-th segment.", func() {
s0 := linear.MakeSeg2(0, 0, 0, 1)
VecExpect(c, p.Seg(0).P, Equals, s0.P)
VecExpect(c, p.Seg(0).Q, Equals, s0.Q)
s1 := linear.MakeSeg2(0, 1, 1, 1)
VecExpect(c, p.Seg(1).P, Equals, s1.P)
VecExpect(c, p.Seg(1).Q, Equals, s1.Q)
s2 := linear.MakeSeg2(1, 1, 1, 0)
VecExpect(c, p.Seg(2).P, Equals, s2.P)
VecExpect(c, p.Seg(2).Q, Equals, s2.Q)
s3 := linear.MakeSeg2(1, 0, 0, 0)
VecExpect(c, p.Seg(3).P, Equals, s3.P)
VecExpect(c, p.Seg(3).Q, Equals, s3.Q)
})
}