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[core] Various cleanup and bug fixes of Perlin processes. (#825)
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@duburcqa
duburcqa authored Jul 14, 2024
1 parent 3306e66 commit e69ea77
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Showing 2 changed files with 45 additions and 42 deletions.
85 changes: 44 additions & 41 deletions core/include/jiminy/core/utilities/random.hxx
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@
namespace jiminy
{
static inline constexpr double PERLIN_NOISE_PERSISTENCE{1.50};
static inline constexpr double PERLIN_NOISE_LACUNARITY{1.15};
static inline constexpr double PERLIN_NOISE_LACUNARITY{0.85};

// ***************************** Uniform random bit generators ***************************** //

Expand Down Expand Up @@ -230,8 +230,7 @@ namespace jiminy
{
JIMINY_THROW(std::invalid_argument, "'wavelength' must be strictly larger than 0.0.");
}
auto gen = uniform_random_bit_generator_ref<uint32_t>{std::random_device{}};
shift_ = uniform(N, 1, gen).cast<double>();
reset(std::random_device{});
}

template<template<unsigned int> class DerivedPerlinNoiseOctave, unsigned int N>
Expand Down Expand Up @@ -297,7 +296,7 @@ namespace jiminy
{
VectorN<int32_t> knot;
VectorN<double> delta;
const auto derived = static_cast<const DerivedPerlinNoiseOctave<N> &>(*this);
const auto & derived = static_cast<const DerivedPerlinNoiseOctave<N> &>(*this);
for (uint32_t k = 0; k < (1U << N); k++)
{
// Mapping from index to knot
Expand Down Expand Up @@ -398,7 +397,7 @@ namespace jiminy
RandomPerlinNoiseOctave<N>::RandomPerlinNoiseOctave(double wavelength) :
AbstractPerlinNoiseOctave<RandomPerlinNoiseOctave, N>(wavelength)
{
seed_ = std::random_device{}();
reset(std::random_device{});
}

template<unsigned int N>
Expand All @@ -408,7 +407,7 @@ namespace jiminy
// Call base implementation
AbstractPerlinNoiseOctave<RandomPerlinNoiseOctave, N>::reset(g);

// Sample new random seed for MurmurHash
// Sample new random seed
seed_ = g();
}

Expand Down Expand Up @@ -502,12 +501,6 @@ namespace jiminy
reset(std::random_device{});
}

template<unsigned int N>
double PeriodicPerlinNoiseOctave<N>::getPeriod() const noexcept
{
return period_;
}

template<unsigned int N>
void PeriodicPerlinNoiseOctave<N>::reset(
const uniform_random_bit_generator_ref<uint32_t> & g) noexcept
Expand All @@ -516,28 +509,25 @@ namespace jiminy
AbstractPerlinNoiseOctave<PeriodicPerlinNoiseOctave, N>::reset(g);

// Re-initialize the pre-computed hash table
std::generate(
grads_.begin(),
grads_.end(),
[&g]() -> VectorN<double>
for (auto & grad : grads_)
{
if constexpr (N == 1)
{
if constexpr (N == 1)
{
return VectorN<double>{uniform(g, -1.0F, 1.0F)};
}
else if constexpr (N == 2)
{
const double theta = 2 * M_PI * uniform(g);
const float radius = std::sqrt(uniform(g));
return VectorN<double>{radius * std::cos(theta), radius * std::sin(theta)};
}
else
{
const VectorN<double> dir = normal(N, 1, g).cast<double>().normalized();
const double radius = std::pow(uniform(g), 1.0 / N);
return radius * dir;
}
});
grad = VectorN<double>{uniform(g, -1.0F, 1.0F)};
}
else if constexpr (N == 2)
{
const double theta = 2 * M_PI * uniform(g);
const float radius = std::sqrt(uniform(g));
grad = VectorN<double>{radius * std::cos(theta), radius * std::sin(theta)};
}
else
{
const VectorN<double> dir = normal(N, 1, g).cast<double>().normalized();
const double radius = std::pow(uniform(g), 1.0 / N);
grad = radius * dir;
}
}
}

template<unsigned int N>
Expand All @@ -562,6 +552,12 @@ namespace jiminy
return grads_[index];
}

template<unsigned int N>
double PeriodicPerlinNoiseOctave<N>::getPeriod() const noexcept
{
return period_;
}

template<template<unsigned int> class DerivedPerlinNoiseOctave, unsigned int N>
AbstractPerlinProcess<DerivedPerlinNoiseOctave, N>::AbstractPerlinProcess(
std::vector<OctaveScalePair> && octaveScalePairs) noexcept :
Expand Down Expand Up @@ -643,19 +639,26 @@ namespace jiminy
static std::vector<std::pair<DerivedPerlinNoiseOctave<N>, const double>>
buildPerlinNoiseOctaves(double wavelength, std::size_t numOctaves, ExtraArgs &&... args)
{
// Make sure that at least one octave has been requested
if (numOctaves < 1)
{
JIMINY_THROW(std::invalid_argument, "'numOctaves' must at least 1.");
}

// Make sure that wavelength of all the octaves is consistent with period if application
if constexpr (std::is_base_of_v<PeriodicPerlinNoiseOctave<N>, DerivedPerlinNoiseOctave<N>>)
{
const double period = std::get<0>(std::tuple{std::forward<ExtraArgs>(args)...});
const double wavelengthMax =
std::pow(PERLIN_NOISE_LACUNARITY, numOctaves) * wavelength;
if (period < wavelengthMax)
const double wavelengthFinal =
wavelength / std::pow(PERLIN_NOISE_LACUNARITY, numOctaves - 1);
if (period < std::max(wavelength, wavelengthFinal))
{
JIMINY_THROW(std::invalid_argument,
"'period' must be larger than (",
"'period' must be larger than the wavelength of all the octaves (",
std::max(wavelength, wavelengthFinal),
"), ie 'wavelength' / ",
PERLIN_NOISE_LACUNARITY,
"^'numOctaves') * 'wavelength' (ie. ",
wavelengthMax,
").");
"^i for i in [1, ..., 'numOctaves'].");
}
}

Expand All @@ -665,7 +668,7 @@ namespace jiminy
for (std::size_t i = 0; i < numOctaves; ++i)
{
octaveScalePairs.emplace_back(DerivedPerlinNoiseOctave<N>(wavelength, args...), scale);
wavelength *= PERLIN_NOISE_LACUNARITY;
wavelength /= PERLIN_NOISE_LACUNARITY;
scale *= PERLIN_NOISE_PERSISTENCE;
}
return octaveScalePairs;
Expand Down
2 changes: 1 addition & 1 deletion core/src/utilities/geometry.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -902,7 +902,7 @@ namespace jiminy
const auto grad = fun.grad(pos);

// Compute the inverse of the normal's Euclidean norm
const double normInv = 1.0 / grad.norm();
const double normInv = 1.0 / std::sqrt(1.0 + grad.squaredNorm());

// Update normal vector
normal.value() << -normInv * grad.template head<2>(), normInv;
Expand Down

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