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Diffstat (limited to 'vendor/github.com/golang/geo/s2/wedge_relations.go')
| -rw-r--r-- | vendor/github.com/golang/geo/s2/wedge_relations.go | 97 |
1 files changed, 0 insertions, 97 deletions
diff --git a/vendor/github.com/golang/geo/s2/wedge_relations.go b/vendor/github.com/golang/geo/s2/wedge_relations.go deleted file mode 100644 index d637bb68c..000000000 --- a/vendor/github.com/golang/geo/s2/wedge_relations.go +++ /dev/null @@ -1,97 +0,0 @@ -// 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 - -// WedgeRel enumerates the possible relation between two wedges A and B. -type WedgeRel int - -// Define the different possible relationships between two wedges. -// -// Given an edge chain (x0, x1, x2), the wedge at x1 is the region to the -// left of the edges. More precisely, it is the set of all rays from x1x0 -// (inclusive) to x1x2 (exclusive) in the *clockwise* direction. -const ( - WedgeEquals WedgeRel = iota // A and B are equal. - WedgeProperlyContains // A is a strict superset of B. - WedgeIsProperlyContained // A is a strict subset of B. - WedgeProperlyOverlaps // A-B, B-A, and A intersect B are non-empty. - WedgeIsDisjoint // A and B are disjoint. -) - -// WedgeRelation reports the relation between two non-empty wedges -// A=(a0, ab1, a2) and B=(b0, ab1, b2). -func WedgeRelation(a0, ab1, a2, b0, b2 Point) WedgeRel { - // There are 6 possible edge orderings at a shared vertex (all - // of these orderings are circular, i.e. abcd == bcda): - // - // (1) a2 b2 b0 a0: A contains B - // (2) a2 a0 b0 b2: B contains A - // (3) a2 a0 b2 b0: A and B are disjoint - // (4) a2 b0 a0 b2: A and B intersect in one wedge - // (5) a2 b2 a0 b0: A and B intersect in one wedge - // (6) a2 b0 b2 a0: A and B intersect in two wedges - // - // We do not distinguish between 4, 5, and 6. - // We pay extra attention when some of the edges overlap. When edges - // overlap, several of these orderings can be satisfied, and we take - // the most specific. - if a0 == b0 && a2 == b2 { - return WedgeEquals - } - - // Cases 1, 2, 5, and 6 - if OrderedCCW(a0, a2, b2, ab1) { - // The cases with this vertex ordering are 1, 5, and 6, - if OrderedCCW(b2, b0, a0, ab1) { - return WedgeProperlyContains - } - - // We are in case 5 or 6, or case 2 if a2 == b2. - if a2 == b2 { - return WedgeIsProperlyContained - } - return WedgeProperlyOverlaps - - } - // We are in case 2, 3, or 4. - if OrderedCCW(a0, b0, b2, ab1) { - return WedgeIsProperlyContained - } - - if OrderedCCW(a0, b0, a2, ab1) { - return WedgeIsDisjoint - } - return WedgeProperlyOverlaps -} - -// WedgeContains reports whether non-empty wedge A=(a0, ab1, a2) contains B=(b0, ab1, b2). -// Equivalent to WedgeRelation == WedgeProperlyContains || WedgeEquals. -func WedgeContains(a0, ab1, a2, b0, b2 Point) bool { - // For A to contain B (where each loop interior is defined to be its left - // side), the CCW edge order around ab1 must be a2 b2 b0 a0. We split - // this test into two parts that test three vertices each. - return OrderedCCW(a2, b2, b0, ab1) && OrderedCCW(b0, a0, a2, ab1) -} - -// WedgeIntersects reports whether non-empty wedge A=(a0, ab1, a2) intersects B=(b0, ab1, b2). -// Equivalent but faster than WedgeRelation != WedgeIsDisjoint -func WedgeIntersects(a0, ab1, a2, b0, b2 Point) bool { - // For A not to intersect B (where each loop interior is defined to be - // its left side), the CCW edge order around ab1 must be a0 b2 b0 a2. - // Note that it's important to write these conditions as negatives - // (!OrderedCCW(a,b,c,o) rather than Ordered(c,b,a,o)) to get correct - // results when two vertices are the same. - return !(OrderedCCW(a0, b2, b0, ab1) && OrderedCCW(b0, a2, a0, ab1)) -} |