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changed permission on func and added maximum error

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made sure that not all functions were public and changed some to private
that need not be exposed.

also added in maximum error to deal with floating point inaccuracies
This commit is contained in:
dm
2016-08-27 20:46:32 -07:00
parent 3850bdc592
commit 9b908a8db1
4 changed files with 26 additions and 23 deletions
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rectangle.go
+23 -20
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@@ -9,7 +9,10 @@ type Rectangle struct {
P1, P2, P3, P4 Point
}
func (r Rectangle) IsRect() bool {
// maximum error used for floating point math
var ɛ = 0.00001
func (r Rectangle) isRect() bool {
// make sure they aren't all just the same point
if (r.P1.X == r.P2.X && r.P1.X == r.P3.X && r.P1.X == r.P4.X) &&
(r.P1.Y == r.P2.Y && r.P1.Y == r.P3.Y && r.P1.Y == r.P4.Y) {
@@ -23,39 +26,39 @@ func (r Rectangle) IsRect() bool {
dd2 := math.Sqrt(math.Abs(cx-r.P2.X)) + math.Sqrt(math.Abs(cy-r.P2.Y))
dd3 := math.Sqrt(math.Abs(cx-r.P3.X)) + math.Sqrt(math.Abs(cy-r.P3.Y))
dd4 := math.Sqrt(math.Abs(cx-r.P4.X)) + math.Sqrt(math.Abs(cy-r.P4.Y))
return dd1 == dd2 && dd1 == dd3 && dd1 == dd4
return math.Abs(dd1-dd2) < ɛ && math.Abs(dd1-dd3) < ɛ && math.Abs(dd1-dd4) < ɛ
}
func (r Rectangle) Neighbors(p Point) (Point, Point) {
func (r Rectangle) neighbors(p Point) (Point, Point) {
keys := []float64{distance(r.P1, p), distance(r.P2, p), distance(r.P3, p), distance(r.P4, p)}
sort.Float64s(keys)
n := []Point{}
d := distance(r.P1, p)
if keys[1] == d || keys[2] == d {
if math.Abs(keys[1]-d) < ɛ || math.Abs(keys[2]-d) < ɛ {
n = append(n, r.P1)
}
d = distance(r.P2, p)
if keys[1] == d || keys[2] == d {
if math.Abs(keys[1]-d) < ɛ || math.Abs(keys[2]-d) < ɛ {
n = append(n, r.P2)
}
d = distance(r.P3, p)
if keys[1] == d || keys[2] == d {
if math.Abs(keys[1]-d) < ɛ || math.Abs(keys[2]-d) < ɛ {
n = append(n, r.P3)
}
d = distance(r.P4, p)
if keys[1] == d || keys[2] == d {
if math.Abs(keys[1]-d) < ɛ || math.Abs(keys[2]-d) < ɛ {
n = append(n, r.P4)
}
return n[0], n[1]
}
func (r Rectangle) Size() float64 {
n1, n2 := r.Neighbors(r.P1)
func (r Rectangle) size() float64 {
n1, n2 := r.neighbors(r.P1)
return distance(r.P1, n1) * distance(r.P1, n2)
}
func (r Rectangle) inOrder() []Point {
n1, n2 := r.Neighbors(r.P1)
n1, n2 := r.neighbors(r.P1)
accross := &Point{}
if r.P2 != n1 || r.P2 != n2 {
accross = &r.P2
@@ -126,26 +129,26 @@ func Intersection(r1, r2 Rectangle) []Point {
}
func sumOfTri(r Rectangle, p Point) bool {
n1, n2 := r.Neighbors(r.P1)
n1, n2 := r.neighbors(r.P1)
x1, x2 := Point{}, Point{}
accross := &Point{}
if r.P2 != n1 || r.P2 != n2 {
accross = &r.P2
x1, x2 = r.Neighbors(r.P2)
x1, x2 = r.neighbors(r.P2)
}
if r.P3 != n1 || r.P3 != n2 {
accross = &r.P3
x1, x2 = r.Neighbors(r.P3)
x1, x2 = r.neighbors(r.P3)
}
if r.P4 != n1 || r.P4 != n2 {
accross = &r.P4
x1, x2 = r.Neighbors(r.P4)
x1, x2 = r.neighbors(r.P4)
}
sumTri := SizeTriangle(r.P1, n1, p) +
SizeTriangle(r.P1, n2, p) +
SizeTriangle(*accross, x1, p) +
SizeTriangle(*accross, x2, p)
if r.Size() == sumTri {
sumTri := sizeTriangle(r.P1, n1, p) +
sizeTriangle(r.P1, n2, p) +
sizeTriangle(*accross, x1, p) +
sizeTriangle(*accross, x2, p)
if math.Abs(r.size()-sumTri) < ɛ {
return true
}
return false
@@ -153,7 +156,7 @@ func sumOfTri(r Rectangle, p Point) bool {
// Containment returns whether r2 is contained inside of r1
func Containment(r1, r2 Rectangle) bool {
if r1.Size() <= r2.Size() {
if r1.size() <= r2.size() {
return false
}
if sumOfTri(r1, r2.P1) && sumOfTri(r1, r2.P2) && sumOfTri(r1, r2.P3) && sumOfTri(r1, r2.P4) {