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// Copyright ©2022 The Gonum Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package r2
import (
"testing"
"golang.org/x/exp/rand"
)
func TestBoxContains(t *testing.T) {
rnd := rand.New(rand.NewSource(1))
for i := 0; i < 200; i++ {
b := randomBox(rnd)
for j := 0; j < 10; j++ {
contained := b.random(rnd)
if !b.Contains(contained) {
t.Error("bounding box should contain Vec")
}
}
uncontained := [4]Vec{
Add(b.Max, Vec{1, 0}),
Add(b.Max, Vec{0, 1}),
Sub(b.Min, Vec{1, 0}),
Sub(b.Min, Vec{0, 1}),
}
for _, unc := range uncontained {
if b.Contains(unc) {
t.Error("box should not contain vec")
}
}
}
}
func TestBoxUnion(t *testing.T) {
rnd := rand.New(rand.NewSource(1))
for i := 0; i < 200; i++ {
b1 := randomBox(rnd)
b2 := randomBox(rnd)
u := b1.Union(b2)
for j := 0; j < 10; j++ {
contained := b1.random(rnd)
if !u.Contains(contained) {
t.Error("union should contain b1's Vec")
}
contained = b2.random(rnd)
if !u.Contains(contained) {
t.Error("union should contain b2's Vec")
}
}
uncontained := [4]Vec{
Add(maxElem(b1.Max, b2.Max), Vec{1, 0}),
Add(maxElem(b1.Max, b2.Max), Vec{0, 1}),
Sub(minElem(b1.Min, b2.Min), Vec{1, 0}),
Sub(minElem(b1.Min, b2.Min), Vec{0, 1}),
}
for _, unc := range uncontained {
if !b1.Contains(unc) && !b2.Contains(unc) && u.Contains(unc) {
t.Error("union should not contain Vec")
}
}
}
}
func TestBoxCenter(t *testing.T) {
const tol = 1e-11
rnd := rand.New(rand.NewSource(1))
for i := 0; i < 300; i++ {
b := randomBox(rnd)
center := b.Center()
size := b.Size()
newBox := centeredBox(center, size)
if b.Empty() {
t.Fatal("random box result must be well formed")
}
if !vecApproxEqual(b.Min, newBox.Min, tol) {
t.Errorf("min values of box not equal. got %g, expected %g", newBox.Min, b.Min)
}
if !vecApproxEqual(b.Max, newBox.Max, tol) {
t.Errorf("max values of box not equal. got %g, expected %g", newBox.Max, b.Max)
}
}
}
func TestBoxAdd(t *testing.T) {
const tol = 1e-14
rnd := rand.New(rand.NewSource(1))
for i := 0; i < 12; i++ {
b := randomBox(rnd)
v := randomVec(rnd)
got := b.Add(v)
want := Box{Min: Add(b.Min, v), Max: Add(b.Max, v)}
if !vecApproxEqual(got.Min, want.Min, tol) {
t.Error("box min incorrect result")
}
if !vecApproxEqual(got.Max, want.Max, tol) {
t.Error("box max incorrect result")
}
}
}
func TestBoxScale(t *testing.T) {
const tol = 1e-11
rnd := rand.New(rand.NewSource(1))
for i := 0; i < 300; i++ {
b := randomBox(rnd)
size := b.Size()
scaler := absElem(randomVec(rnd))
scaled := b.Scale(scaler)
gotScaler := divElem(scaled.Size(), size)
if !vecApproxEqual(scaler, gotScaler, tol) {
t.Errorf("got scaled %g, expected %g", gotScaler, scaler)
}
center := b.Center()
scaledCenter := scaled.Center()
if !vecApproxEqual(center, scaledCenter, tol) {
t.Error("scale modified center")
}
}
}
func TestBoxEmpty(t *testing.T) {
rnd := rand.New(rand.NewSource(1))
for i := 0; i < 300; i++ {
v := absElem(randomVec(rnd))
b := randomBox(rnd)
min := b.Min
max := b.Max
if !(Box{Min: min, Max: min}).Empty() {
t.Error("Box{min,min} should be empty")
}
if !(Box{Min: max, Max: max}).Empty() {
t.Error("Box{max,max} should be empty")
}
bmm := Box{Min: min, Max: Sub(min, v)}
if !bmm.Empty() {
t.Error("Box{min,min-v} should be empty")
} else if bmm.Canon().Empty() {
t.Error("Canonical box of Box{min,min-v} is not empty")
}
bMM := Box{Min: Add(max, v), Max: max}
if !bMM.Empty() {
t.Error("Box{max+v,max} should be empty")
} else if bmm.Canon().Empty() {
t.Error("Canonical box of Box{max+v,max} is not empty")
}
}
}
func TestBoxCanon(t *testing.T) {
rnd := rand.New(rand.NewSource(1))
for i := 0; i < 300; i++ {
b := randomBox(rnd)
badBox := Box{Min: b.Max, Max: b.Min}
canon := badBox.Canon()
if canon != b {
t.Error("swapped box canon should be equal to original box")
}
}
}
func TestBoxVertices(t *testing.T) {
rnd := rand.New(rand.NewSource(1))
for i := 0; i < 300; i++ {
b := randomBox(rnd)
gots := b.Vertices()
wants := goldenVertices(b)
if len(gots) != len(wants) {
t.Fatalf("bad length of vertices. expect 4, got %d", len(gots))
}
for j, want := range wants {
got := gots[j]
if !vecEqual(want, got) {
t.Errorf("%dth vertex not equal", j)
}
}
}
}
// randomBox returns a random valid bounding Box.
func randomBox(rnd *rand.Rand) Box {
spatialScale := randomRange(0, 2000)
boxScale := randomRange(0.01, 1000)
return centeredBox(Scale(spatialScale, randomVec(rnd)), Scale(boxScale, absElem(randomVec(rnd))))
}
// Random returns a random point within the Box.
// used to facilitate testing
func (b Box) random(rnd *rand.Rand) Vec {
return Vec{
X: randomRange(b.Min.X, b.Max.X),
Y: randomRange(b.Min.Y, b.Max.Y),
}
}
// randomRange returns a random float64 [a,b)
func randomRange(a, b float64) float64 {
return a + (b-a)*rand.Float64()
}
func goldenVertices(a Box) []Vec {
return []Vec{
0: a.Min,
1: {a.Max.X, a.Min.Y},
2: a.Max,
3: {a.Min.X, a.Max.Y},
}
}
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