Function TestPolygonShape

s2/polygon_test.go:235–291

(t *testing.T)

}

func TestPolygonShape(t *testing.T) {
	const numLoops = 100
	const numVerticesPerLoop = 6
	concentric := concentricLoopsPolygon(PointFromCoords(1, 0, 0), numLoops, numVerticesPerLoop)

	tests := []struct {
		p *Polygon
	}{
		{near0Polygon},    // one loop polygon
		{near0231Polygon}, // several loops polygon
		{concentric},      // many loops polygon
	}

	for _, test := range tests {
		shape := Shape(test.p)

		if got, want := shape.NumEdges(), test.p.numVertices; got != want {
			t.Errorf("the number of vertices in a polygon should equal the number of edges. got %v, want %v", got, want)
		}
		if got, want := shape.NumChains(), test.p.NumLoops(); got != want {
			t.Errorf("the number of loops in a polygon should equal the number of chains. got %v, want %v", got, want)
		}

		edgeID := 0
		for i, l := range test.p.loops {
			if edgeID != shape.Chain(i).Start {
				t.Errorf("the edge id of the start of loop(%d) should equal the sum of vertices so far in the polygon. got %d, want %d", i, shape.Chain(i).Start, edgeID)
			}
			if len(l.vertices) != shape.Chain(i).Length {
				t.Errorf("the length of Chain(%d) should equal the length of loop(%d), got %v, want %v", i, i, shape.Chain(i).Length, len(l.vertices))
			}
			for j := 0; j < len(l.Vertices()); j++ {
				edge := shape.Edge(edgeID)
				if l.OrientedVertex(j) != edge.V0 {
					t.Errorf("l.Vertex(%d) = %v, want %v", j, l.Vertex(j), edge.V0)
				}
				if l.OrientedVertex(j+1) != edge.V1 {
					t.Errorf("l.Vertex(%d) = %v, want %v", j+1, l.Vertex(j+1), edge.V1)
				}
				edgeID++
			}
		}
		if got, want := shape.Dimension(), 2; got != want {
			t.Errorf("shape.Dimension() = %v, want %v", got, want)
		}
		if shape.IsEmpty() {
			t.Errorf("shape.IsEmpty() = true, want false")
		}
		if shape.IsFull() {
			t.Errorf("shape.IsFull() = true, want false")
		}

		if got, want := test.p.ContainsPoint(OriginPoint()), shape.ReferencePoint().Contained; got != want {
			t.Errorf("p.ContainsPoint(OriginPoint()) != shape.ReferencePoint().Contained")
		}
	}
}