func (w *fluxWindow) animate() {
target := <-w.target
vel := ZP
for {
next := time.After(time.Second / fps)
r := ZR
Do(w, func() {
Pan(w, Rect(w).Min.Add(vel.Div(fps)))
r = Rect(w)
})
d := target.Sub(r.Center())
d.X = math.Copysign(math.Max(0, math.Abs(d.X)-r.Dx()/3), d.X)
d.Y = math.Copysign(math.Max(0, math.Abs(d.Y)-r.Dy()/3), d.Y)
vel = vel.Add(d).Mul(.8)
if vel.Len() < .1 {
next = nil
}
select {
case <-next:
case target = <-w.target:
case <-w.pause:
target = <-w.target
}
}
}
// negative zero is a good test because:
// 1) 0 and -0 are equal, yet have distinct representations.
// 2) 0 is represented as all zeros, -0 isn't.
// I'm not sure the language spec actually requires this behavior,
// but it's what the current map implementation does.
func TestNegativeZero(t *testing.T) {
m := make(map[float64]bool, 0)
m[+0.0] = true
m[math.Copysign(0.0, -1.0)] = true // should overwrite +0 entry
if len(m) != 1 {
t.Error("length wrong")
}
/* gccgo fails this test; this is not required by the spec.
for k := range m {
if math.Copysign(1.0, k) > 0 {
t.Error("wrong sign")
}
}
*/
m = make(map[float64]bool, 0)
m[math.Copysign(0.0, -1.0)] = true
m[+0.0] = true // should overwrite -0.0 entry
if len(m) != 1 {
t.Error("length wrong")
}
/* gccgo fails this test; this is not required by the spec.
for k := range m {
if math.Copysign(1.0, k) < 0 {
t.Error("wrong sign")
}
}
*/
}
// negative zero is a good test because:
// 1) 0 and -0 are equal, yet have distinct representations.
// 2) 0 is represented as all zeros, -0 isn't.
// I'm not sure the language spec actually requires this behavior,
// but it's what the current map implementation does.
func TestNegativeZero(t *testing.T) {
m := make(map[float64]bool, 0)
m[+0.0] = true
m[math.Copysign(0.0, -1.0)] = true // should overwrite +0 entry
if len(m) != 1 {
t.Error("length wrong")
}
for k := range m {
if math.Copysign(1.0, k) > 0 {
t.Error("wrong sign")
}
}
m = make(map[float64]bool, 0)
m[math.Copysign(0.0, -1.0)] = true
m[+0.0] = true // should overwrite -0.0 entry
if len(m) != 1 {
t.Error("length wrong")
}
for k := range m {
if math.Copysign(1.0, k) < 0 {
t.Error("wrong sign")
}
}
}
// DrotG gives plane rotation
//
// _ _ _ _ _ _
// | c s | | a | | r |
// | -s c | * | b | = | 0 |
// _ _ _ _ _ _
//
// r = ±(a^2 + b^2)
// c = a/r, the cosine of the plane rotation
// s = b/r, the sine of the plane rotation
//
// NOTE: Netlib library seems to give a different
// sign for r when a or b is zero than other implementations
// and different than BLAS technical manual
func (Blas) Drotg(a, b float64) (c, s, r, z float64) {
if b == 0 && a == 0 {
return 1, 0, a, 0
}
/*
if a == 0 {
if b > 0 {
return 0, 1, b, 1
}
return 0, -1, -b, 1
}
*/
absA := math.Abs(a)
absB := math.Abs(b)
aGTb := absA > absB
r = math.Hypot(a, b)
if aGTb {
r = math.Copysign(r, a)
} else {
r = math.Copysign(r, b)
}
c = a / r
s = b / r
if aGTb {
z = s
} else if c != 0 { // r == 0 case handled above
z = 1 / c
} else {
z = 1
}
return
}
// Smoothly rotates the entity from its current rotation to the target
// rotation
func esRotateToTarget(r RotationComponent, t *targetRotationComponent) {
py, pp := r.Yaw(), r.Pitch()
ty, tp := t.TargetYaw(), t.TargetPitch()
if t.pPitch != tp || t.pYaw != ty || t.time >= 4 {
t.sYaw, t.sPitch = py, pp
t.time = 0
t.pPitch = tp
t.pYaw = ty
}
sy, sp := t.sYaw, t.sPitch
dy, dp := ty-sy, tp-sp
// Make sure we go for the shortest route.
// e.g. (in degrees) 1 to 359 is quicker
// to decrease to wrap around than it is
// to increase all the way around
if dy > math.Pi || dy < -math.Pi {
sy += math.Copysign(math.Pi*2, dy)
dy = ty - sy
}
if dp > math.Pi || dp < -math.Pi {
sp += math.Copysign(math.Pi*2, dp)
dp = tp - sp
}
t.time = math.Min(4.0, t.time+Client.delta)
py = sy + dy*(1/4.0)*t.time
pp = sp + dp*(1/4.0)*t.time
r.SetPitch(pp)
r.SetYaw(py)
}
func TestGrowWithNegativeZero(t *testing.T) {
t.Skip("fails with gccgo")
negzero := math.Copysign(0.0, -1.0)
m := make(map[FloatInt]int, 4)
m[FloatInt{0.0, 0}] = 1
m[FloatInt{0.0, 1}] = 2
m[FloatInt{0.0, 2}] = 4
m[FloatInt{0.0, 3}] = 8
growflag := true
s := 0
cnt := 0
negcnt := 0
// The first iteration should return the +0 key.
// The subsequent iterations should return the -0 key.
// I'm not really sure this is required by the spec,
// but it makes sense.
// TODO: are we allowed to get the first entry returned again???
for k, v := range m {
if v == 0 {
continue
} // ignore entries added to grow table
cnt++
if math.Copysign(1.0, k.x) < 0 {
if v&16 == 0 {
t.Error("key/value not updated together 1")
}
negcnt++
s |= v & 15
} else {
if v&16 == 16 {
t.Error("key/value not updated together 2", k, v)
}
s |= v
}
if growflag {
// force a hashtable resize
for i := 0; i < 100; i++ {
m[FloatInt{3.0, i}] = 0
}
// then change all the entries
// to negative zero
m[FloatInt{negzero, 0}] = 1 | 16
m[FloatInt{negzero, 1}] = 2 | 16
m[FloatInt{negzero, 2}] = 4 | 16
m[FloatInt{negzero, 3}] = 8 | 16
growflag = false
}
}
if s != 15 {
t.Error("entry missing", s)
}
if cnt != 4 {
t.Error("wrong number of entries returned by iterator", cnt)
}
if negcnt != 3 {
t.Error("update to negzero missed by iteration", negcnt)
}
}
func same(f, g float64) bool {
if math.IsNaN(f) && math.IsNaN(g) {
return true
}
if math.Copysign(1, f) != math.Copysign(1, g) {
return false
}
return f == g
}
//RoundInt - rounds integers to a place:
// Example: RoundInt(12345, 3) would return 12000
func RoundInt(num, places int) int {
_num := float64(num)
factor := int(math.Pow(10, float64(places)))
_div := int(math.Abs(_num)) / factor
_mod := int(math.Abs(_num)) % factor
if (_mod) >= (factor / 2) {
return int(math.Copysign(float64(((_div + 1) * factor)), _num))
}
return int(math.Copysign(float64(((_div) * factor)), _num))
}
// Round rounds a value. RoundOn is usually .5.
func Round(val float64, roundOn float64, places int) float64 {
pow := math.Pow(10, float64(places))
digit := pow * val
_, div := math.Modf(digit)
_div := math.Copysign(div, val)
_roundOn := math.Copysign(roundOn, val)
if _div >= _roundOn {
return math.Ceil(digit) / pow
}
return math.Floor(digit) / pow
}
func TestRoundTrips(t *testing.T) {
assertRoundTrips := func(v Value) {
vs := NewTestValueStore()
out := DecodeValue(EncodeValue(v, vs), vs)
assert.True(t, v.Equals(out))
}
assertRoundTrips(Bool(false))
assertRoundTrips(Bool(true))
assertRoundTrips(Number(0))
assertRoundTrips(Number(-0))
assertRoundTrips(Number(math.Copysign(0, -1)))
intTest := []int64{1, 2, 3, 7, 15, 16, 17,
127, 128, 129,
254, 255, 256, 257,
1023, 1024, 1025,
2048, 4096, 8192, 32767, 32768, 65535, 65536,
4294967295, 4294967296,
9223372036854779,
92233720368547760,
}
for _, v := range intTest {
f := float64(v)
assertRoundTrips(Number(f))
f = math.Copysign(f, -1)
assertRoundTrips(Number(f))
}
floatTest := []float64{1.01, 1.001, 1.0001, 1.00001, 1.000001, 100.01, 1000.000001}
for _, f := range floatTest {
assertRoundTrips(Number(f))
f = math.Copysign(f, -1)
assertRoundTrips(Number(f))
}
assertRoundTrips(Number(math.MaxFloat64))
assertRoundTrips(Number(math.Nextafter(1, 2) - 1))
assertRoundTrips(String(""))
assertRoundTrips(String("foo"))
assertRoundTrips(String("AINT NO THANG"))
assertRoundTrips(String("💩"))
assertRoundTrips(NewStruct("", StructData{"a": Bool(true), "b": String("foo"), "c": Number(2.3)}))
listLeaf := newList(newListLeafSequence(nil, Number(4), Number(5), Number(6), Number(7)))
assertRoundTrips(listLeaf)
assertRoundTrips(newList(newListMetaSequence([]metaTuple{
newMetaTuple(NewRef(listLeaf), orderedKeyFromInt(10), 10, nil),
newMetaTuple(NewRef(listLeaf), orderedKeyFromInt(20), 20, nil),
}, nil)))
}
func Quaternion(m glm.Mat3d) glm.Quatd {
q := glm.Quatd{}
m00, m01, m02 := m[0], m[1], m[2]
m10, m11, m12 := m[3], m[4], m[5]
m20, m21, m22 := m[6], m[7], m[8]
q.W = math.Sqrt(math.Max(0, 1+m00+m11+m22)) / 2
q.V[0] = math.Copysign(math.Sqrt(math.Max(0, 1+m00-m11-m22))/2, m12-m21)
q.V[1] = math.Copysign(math.Sqrt(math.Max(0, 1-m00+m11-m22))/2, m20-m02)
q.V[2] = math.Copysign(math.Sqrt(math.Max(0, 1-m00-m11+m22))/2, m01-m10)
return q
}
// round is the "missing" round function from the math lib
func round(val float64, roundOn float64, places int) float64 {
var round float64
pow := math.Pow(10, float64(places))
digit := pow * val
_, div := math.Modf(digit)
_div := math.Copysign(div, val)
_roundOn := math.Copysign(roundOn, val)
if _div >= _roundOn {
round = math.Ceil(digit)
} else {
round = math.Floor(digit)
}
return round / pow
}
func (f ExactFloat) ToDoubleHelper() float64 {
sign := float64(f.sign)
if !f.is_normal() {
if f.is_zero() {
return math.Copysign(0, sign)
}
if f.is_inf() {
return math.Inf(f.sign)
}
return math.Copysign(math.NaN(), sign)
}
mantissa := f.bn.Uint64()
return sign * math.Ldexp(float64(mantissa), f.bn_exp)
}
func (sh *Shoehorn) Rprop(S [][]float64, G0 [][]float64, G1 [][]float64, step_size_min float64, step_size_max float64) {
var (
o, d int
gprod float64
)
for o = 0; o < sh.no; o++ {
for d = 0; d < sh.nd; d++ {
// Update the step size (consistent gradient directions get a boost, inconsistent directions get reduced).
gprod = G0[o][d] * G1[o][d]
if gprod > 0. {
S[o][d] *= 1.01
} else if gprod < 0. {
S[o][d] *= 0.5
}
// Apply caps.
if S[o][d] < step_size_min {
S[o][d] = step_size_min
}
if S[o][d] > step_size_max {
S[o][d] = step_size_max
}
// Update the position based on the sign of its magnitude and the learned step size (RProp doesn't use gradient magnitudes).
if (gprod > 0.) && (G1[o][d] != 0.) {
sh.L[o][d] -= math.Copysign(S[o][d], G1[o][d])
}
}
}
}
func TestToString(t *testing.T) {
tests := []struct {
a ExactFloat
want string
}{
{NewExactFloat(math.NaN()), "nan"},
{NewExactFloat(math.Inf(1)), "inf"},
{NewExactFloat(math.Inf(-1)), "-inf"},
{NewExactFloat(0), "0"},
{NewExactFloat(math.Copysign(0, -1)), "-0"},
{NewExactFloat(1.0), "1"},
{NewExactFloat(1.5), "1.5"},
{NewExactFloat(1. / 512), "0.001953125"},
{NewExactFloat(1.23456789), "1.2345678899999999"},
{NewExactFloat(math.SmallestNonzeroFloat64), "4.9406564584124654e-324"},
{NewExactFloat(math.MaxFloat64), "1.7976931348623157e+308"},
{NewExactFloat(math.MaxFloat64).Add(NewExactFloat(math.MaxFloat64)), "3.59538626972463142e+308"},
}
for _, test := range tests {
got := test.a.ToString()
if got != test.want {
t.Errorf("%v.ToString() = %s, want %s", test.a, got, test.want)
}
}
}
// Compute Wilkinson shift from symmetric 2x2 trailing submatrix
// Stable formula from Hogben 2007, 42.3
func wilkinson(tn1, tnn1, tn float64) float64 {
var d, tsq float64
d = (tn1 - tn) / 2.0
tsq = math.Hypot(d, tnn1)
u := tn - math.Copysign((tnn1/(math.Abs(d)+tsq))*tnn1, d)
return u
}
// RoundFloat rounds float val to the nearest integer value with float64 format, like MySQL Round function.
// RoundFloat uses default rounding mode, see https://dev.mysql.com/doc/refman/5.7/en/precision-math-rounding.html
// so rounding use "round half away from zero".
// e.g, 1.5 -> 2, -1.5 -> -2.
func RoundFloat(f float64) float64 {
if math.Abs(f) < 0.5 {
return 0
}
return math.Trunc(f + math.Copysign(0.5, f))
}
func builtinMath_round(call FunctionCall) Value {
number := toFloat(call.Argument(0))
value := math.Floor(number + 0.5)
if value == 0 {
value = math.Copysign(0, number)
}
return toValue(value)
}
func TestFloat64(t *testing.T) {
base := []float64{
0,
math.Copysign(0, -1),
-1,
1,
math.NaN(),
math.Inf(+1),
math.Inf(-1),
0.1,
1.5,
1.9999999999999998, // all 1s mantissa
1.3333333333333333, // 1.010101010101...
1.1428571428571428, // 1.001001001001...
1.112536929253601e-308, // first normal
2,
4,
8,
16,
32,
64,
128,
256,
3,
12,
1234,
123456,
-0.1,
-1.5,
-1.9999999999999998,
-1.3333333333333333,
-1.1428571428571428,
-2,
-3,
1e-200,
1e-300,
1e-310,
5e-324,
1e-105,
1e-305,
1e+200,
1e+306,
1e+307,
1e+308,
}
all := make([]float64, 200)
copy(all, base)
for i := len(base); i < len(all); i++ {
all[i] = rand.NormFloat64()
}
test(t, "+", add, fop(Fadd64), all)
test(t, "-", sub, fop(Fsub64), all)
if GOARCH != "386" { // 386 is not precise!
test(t, "*", mul, fop(Fmul64), all)
test(t, "/", div, fop(Fdiv64), all)
}
}
func TestCopySign(t *testing.T) {
f := func(x struct{ X, Y float32 }) bool {
y := Copysign(x.X, x.Y)
return y == float32(math.Copysign(float64(x.X), float64(x.Y)))
}
if err := quick.Check(f, nil); err != nil {
t.Error(err)
}
}
func formatFloat(x float64, fmt byte, prec int) string {
s := strconv.FormatFloat(x, fmt, prec, 64)
// Protect against negative zero.
z := strconv.FormatFloat(math.Copysign(0, -1), fmt, prec, 64)
if s == z {
return strconv.FormatFloat(0, fmt, prec, 64)
}
return s
}
// Tries to parse a Geo degrees value from a string as it was found in some
// EXIF data.
// Supported formats so far:
// - "52,00000,50,00000,34,01180" ==> 52 deg 50'34.0118"
// Probably due to locale the comma is used as decimal mark as well as the
// separator of three floats (degrees, minutes, seconds)
// http://en.wikipedia.org/wiki/Decimal_mark#Hindu.E2.80.93Arabic_numeral_system
// - "52.0,50.0,34.01180" ==> 52deg50'34.0118"
// - "52,50,34.01180" ==> 52deg50'34.0118"
func parseTagDegreesString(s string) (float64, error) {
const unparsableErrorFmt = "Unknown coordinate format: %s"
isSplitRune := func(c rune) bool {
return c == ',' || c == ';'
}
parts := strings.FieldsFunc(s, isSplitRune)
var degrees, minutes, seconds float64
var err error
switch len(parts) {
case 6:
degrees, err = strconv.ParseFloat(parts[0]+"."+parts[1], 64)
if err != nil {
return 0.0, fmt.Errorf(unparsableErrorFmt, s)
}
minutes, err = strconv.ParseFloat(parts[2]+"."+parts[3], 64)
if err != nil {
return 0.0, fmt.Errorf(unparsableErrorFmt, s)
}
minutes = math.Copysign(minutes, degrees)
seconds, err = strconv.ParseFloat(parts[4]+"."+parts[5], 64)
if err != nil {
return 0.0, fmt.Errorf(unparsableErrorFmt, s)
}
seconds = math.Copysign(seconds, degrees)
case 3:
degrees, err = strconv.ParseFloat(parts[0], 64)
if err != nil {
return 0.0, fmt.Errorf(unparsableErrorFmt, s)
}
minutes, err = strconv.ParseFloat(parts[1], 64)
if err != nil {
return 0.0, fmt.Errorf(unparsableErrorFmt, s)
}
minutes = math.Copysign(minutes, degrees)
seconds, err = strconv.ParseFloat(parts[2], 64)
if err != nil {
return 0.0, fmt.Errorf(unparsableErrorFmt, s)
}
seconds = math.Copysign(seconds, degrees)
default:
return 0.0, fmt.Errorf(unparsableErrorFmt, s)
}
return degrees + minutes/60.0 + seconds/3600.0, nil
}
func (ai *FollowAI) Act(db *engine.EntityDB, eid engine.Entity) {
epos := db.Get(eid, "position").(*base.Position)
tpos := db.Get(ai.Target, "position").(*base.Position)
dx, dy := int64(0), int64(0)
if epos.X > tpos.X+1 || epos.X < tpos.X-1 {
dx = int64(math.Copysign(1, float64(tpos.X-epos.X)))
}
if epos.Y > tpos.Y+1 || epos.Y < tpos.Y-1 {
dy = int64(math.Copysign(1, float64(tpos.Y-epos.Y)))
}
// Since the bat is situated at z-level 2, it will never find
// a wall with art symbol '#' at one level below, so this move
// function still allows the bat to fly over stones! ^_^
// Hence the "+1" for the z; so the bat stays one level above
// the player.
base.HelperMove(db, eid, dx, dy, tpos.Z-epos.Z+1)
}
func (a *Actor) UpdateAI(currScene *Scene) {
var m Vector2d
if Distance(a.Pos, currScene.PC.Pos) < 160 {
a.Chasing = true
a.MvStack = Vector2d{
(currScene.PC.Pos.X - a.Pos.X) / a.Speed.X,
(currScene.PC.Pos.Y - a.Pos.Y) / a.Speed.Y,
}
} else {
a.Chasing = false
}
if a.MvStack.X > 0 {
m = MVSpeed.Right
a.MvStack.X -= 1
}
if a.MvStack.X < 0 {
m = MVSpeed.Left
a.MvStack.X += 1
}
if a.MvStack.Y > 0 {
m = MVSpeed.Down
a.MvStack.Y -= 1
}
if a.MvStack.Y < 0 {
m = MVSpeed.Up
a.MvStack.Y += 1
}
a.Move(m, currScene)
// logic for npc wandering
if !a.Chasing && a.MvStack.X == 0 && a.MvStack.Y == 0 {
a.MvStack = Vector2d{
rand.Int31n(3*tileSize) * int32(math.Copysign(1.0, float64(rand.Int31n(1))-1.0)),
rand.Int31n(3*tileSize) * int32(math.Copysign(1.0, float64(rand.Int31n(1))-1.0)),
}
}
}
func (t Tournament) Ranks() []float64 {
m := t.Matrix()
eig := mat64.Eigen(m, 1e-10)
_, c := eig.V.Dims()
var ranks []float64
for i := 0; i < c; i++ {
ranks = eig.V.Col(nil, i)
sense := math.Copysign(1, ranks[0])
for _, val := range ranks {
if sense == 0 {
sense = math.Copysign(1, val)
}
if val*sense < 0 {
ranks = nil
break
}
}
if ranks != nil {
min := 1e100
max := 0.0
for i := range ranks {
col := t.Matrix().Col(nil, i)
row := t.Matrix().Row(nil, i)
tot := 0.0
for j := range col {
tot += col[j] + row[j]
}
ranks[i] = ranks[i] * sense / tot // normalize to # games
min = math.Min(ranks[i], min)
max = math.Max(ranks[i], max)
}
// uncomment this to make min score = 0 and max score = 1
//for i := range ranks {
// ranks[i] = (ranks[i] - min) / (max - min)
//}
break
}
}
return ranks
}
func (h histogrammer) gv(v float64) string {
if math.IsNaN(v) || math.IsInf(v, 0) {
return fmt.Sprint(v)
}
c := "+"
if v < 0 {
c = "-"
}
v = math.Abs(math.Trunc(v + math.Copysign(0.5, v))) // Abs(Round(v))
return strings.Repeat(c, int(v))
}
func TestSignedZeroAndInfinity(t *testing.T) {
tests := []struct {
f ExactFloat
want float64
}{
{SignedZero(1), math.Copysign(0, 1)},
{SignedZero(-1), math.Copysign(0, -1)},
{Infinity(1), math.Inf(1)},
{Infinity(-1), math.Inf(-1)},
}
for _, test := range tests {
var wantsign int
if math.Signbit(test.want) {
wantsign = -1
} else {
wantsign = 1
}
if test.f.sign != wantsign {
t.Errorf("sign %v: got %d, want %d", test.f, test.f.sign, wantsign)
}
}
}
// Dlarfg generates an elementary reflector for a Householder matrix. It creates
// a real elementary reflector of order n such that
// H * (alpha) = (beta)
// ( x) ( 0)
// H^T * H = I
// H is represented in the form
// H = 1 - tau * (1; v) * (1 v^T)
// where tau is a real scalar.
//
// On entry, x contains the vector x, on exit it contains v.
func (impl Implementation) Dlarfg(n int, alpha float64, x []float64, incX int) (beta, tau float64) {
if n < 0 {
panic(nLT0)
}
if n <= 1 {
return alpha, 0
}
checkVector(n-1, x, incX)
bi := blas64.Implementation()
xnorm := bi.Dnrm2(n-1, x, incX)
if xnorm == 0 {
return alpha, 0
}
beta = -math.Copysign(impl.Dlapy2(alpha, xnorm), alpha)
safmin := dlamchS / dlamchE
knt := 0
if math.Abs(beta) < safmin {
// xnorm and beta may be innacurate, scale x and recompute.
rsafmn := 1 / safmin
for {
knt++
bi.Dscal(n-1, rsafmn, x, incX)
beta *= rsafmn
alpha *= rsafmn
if math.Abs(beta) >= safmin {
break
}
}
xnorm = bi.Dnrm2(n-1, x, incX)
beta = -math.Copysign(impl.Dlapy2(alpha, xnorm), alpha)
}
tau = (beta - alpha) / beta
bi.Dscal(n-1, 1/(alpha-beta), x, incX)
for j := 0; j < knt; j++ {
beta *= safmin
}
return beta, tau
}
func TestToDouble(t *testing.T) {
tests := []struct {
f ExactFloat
want float64
}{
{NewExactFloat(0.0), 0.0},
{NewExactFloat(math.Copysign(0, -1)), math.Copysign(0, -1)},
{NewExactFloat(1.0), 1.0},
{NewExactFloat(-1.0), -1.0},
{NewExactFloat(2.5), 2.5},
{NewExactFloat(-2.5), -2.5},
{NewExactFloat(math.SmallestNonzeroFloat64), math.SmallestNonzeroFloat64},
{NewExactFloat(math.MaxFloat64), math.MaxFloat64},
{NewExactFloat(12345.6789), 12345.6789},
{NewExactFloat(-12345.6789), -12345.6789},
}
for _, test := range tests {
got := test.f.ToDouble()
if got != test.want {
t.Errorf("%v.ToDouble() = %v, want %v", test.f, got, test.want)
}
}
}
func limitedNewRadius(lastRadius, newRadius, length float64) float64 {
// with undefined values, anything new passes
if math.IsNaN(lastRadius + length) {
return newRadius
}
radiusSlope := (newRadius - lastRadius) / length
if math.Abs(radiusSlope) > maxRadiusSlope {
return lastRadius + math.Copysign(maxRadiusSlope*length, radiusSlope)
//newRadius += math.Copysign(maxDeltaRadius, deltaRadius) - deltaRadius
//fmt.Println("would have had", nextRadius, "and now have", newRadius)
}
return newRadius
}