1 files changed, 63 insertions, 0 deletions
diff --git a/vendor/github.com/golang/geo/s2/contains_vertex_query.go b/vendor/github.com/golang/geo/s2/contains_vertex_query.go
new file mode 100644
index 000000000..8e74f9e5b
--- /dev/null
+++ b/vendor/github.com/golang/geo/s2/contains_vertex_query.go
@@ -0,0 +1,63 @@
+// Copyright 2017 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package s2
+
+// ContainsVertexQuery is used to track the edges entering and leaving the
+// given vertex of a Polygon in order to be able to determine if the point is
+// contained by the Polygon.
+//
+// Point containment is defined according to the semi-open boundary model
+// which means that if several polygons tile the region around a vertex,
+// then exactly one of those polygons contains that vertex.
+type ContainsVertexQuery struct {
+	target  Point
+	edgeMap map[Point]int
+}
+
+// NewContainsVertexQuery returns a new query for the given vertex whose
+// containment will be determined.
+func NewContainsVertexQuery(target Point) *ContainsVertexQuery {
+	return &ContainsVertexQuery{
+		target:  target,
+		edgeMap: make(map[Point]int),
+	}
+}
+
+// AddEdge adds the edge between target and v with the given direction.
+// (+1 = outgoing, -1 = incoming, 0 = degenerate).
+func (q *ContainsVertexQuery) AddEdge(v Point, direction int) {
+	q.edgeMap[v] += direction
+}
+
+// ContainsVertex reports a +1 if the target vertex is contained, -1 if it is
+// not contained, and 0 if the incident edges consisted of matched sibling pairs.
+func (q *ContainsVertexQuery) ContainsVertex() int {
+	// Find the unmatched edge that is immediately clockwise from Ortho(P).
+	referenceDir := Point{q.target.Ortho()}
+
+	bestPoint := referenceDir
+	bestDir := 0
+
+	for k, v := range q.edgeMap {
+		if v == 0 {
+			continue // This is a "matched" edge.
+		}
+		if OrderedCCW(referenceDir, bestPoint, k, q.target) {
+			bestPoint = k
+			bestDir = v
+		}
+	}
+	return bestDir
+}