inline void operator() (ustring name, Dual2<R> &result,
const Dual2<S> &s, const Dual2<T> &t,
ShaderGlobals *sg, const NoiseParams *opt) const {
if (name == Strings::uperlin || name == Strings::noise) {
Noise noise;
noise(result, s, t);
} else if (name == Strings::perlin || name == Strings::snoise) {
SNoise snoise;
snoise(result, s, t);
} else if (name == Strings::simplexnoise || name == Strings::simplex) {
SimplexNoise simplexnoise;
simplexnoise(result, s, t);
} else if (name == Strings::usimplexnoise || name == Strings::usimplex) {
USimplexNoise usimplexnoise;
usimplexnoise(result, s, t);
} else if (name == Strings::cell) {
CellNoise cellnoise;
cellnoise(result.val(), s.val(), t.val());
result.clear_d();
} else if (name == Strings::gabor) {
GaborNoise gnoise;
gnoise (name, result, s, t, sg, opt);
} else {
((ShadingContext *)sg->context)->error ("Unknown noise type \"%s\"", name.c_str());
}
}
inline void operator() (ustring name, Dual2<R> &result, const Dual2<S> &s,
const S &sp,
ShaderGlobals *sg, const NoiseParams *opt) const {
if (name == Strings::uperlin || name == Strings::noise) {
PeriodicNoise noise;
noise(result, s, sp);
} else if (name == Strings::perlin || name == Strings::snoise) {
PeriodicSNoise snoise;
snoise(result, s, sp);
} else if (name == Strings::cell) {
PeriodicCellNoise cellnoise;
cellnoise(result.val(), s.val(), sp);
result.clear_d();
} else if (name == Strings::gabor) {
GaborPNoise gnoise;
gnoise (name, result, s, sp, sg, opt);
} else {
((ShadingContext *)sg->context)->error ("Unknown noise type \"%s\"", name.c_str());
}
}
inline Dual2<float> safe_fmod (const Dual2<float> &a, const Dual2<float> &b) {
return Dual2<float> (safe_fmod (a.val(), b.val()), a.dx(), a.dy());
}
inline Dual2<float> fabsf (const Dual2<float> &x) {
return x.val() >= 0 ? x : -x;
}
// Helper function: per-component 'floor' of a Dual2<Vec3>.
inline Vec3
floor (const Dual2<Vec3> &vd)
{
const Vec3 &v (vd.val());
return Vec3 (floorf(v[0]), floorf(v[1]), floorf(v[2]));
}
// Evaluate the summed contribution of all gabor impulses within the
// cell whose corner is c_i. x_c_i is vector from x (the point
// we are trying to evaluate noise at) and c_i.
Dual2<float>
gabor_cell (GaborParams &gp, const Vec3 &c_i, const Dual2<Vec3> &x_c_i,
int seed = 0)
{
fast_rng rng (gp.periodic ? Vec3(wrap(c_i,gp.period)) : c_i, seed);
int n_impulses = rng.poisson (gp.lambda * gp.radius3);
Dual2<float> sum = 0;
for (int i = 0; i < n_impulses; i++) {
// OLD code: Vec3 x_i_c (rng(), rng(), rng());
// Turned out that C++ spec says order of args are unspecified.
// gcc appeared to do right-to-left, so to make sure our noise
// function is locked down (and works identically for clang,
// which evaluates left-to-right), we ask for the rng() calls
// one at a time and match the way it looked before.
float z_rng = rng(), y_rng = rng(), x_rng = rng();
Vec3 x_i_c (x_rng, y_rng, z_rng);
Dual2<Vec3> x_k_i = gp.radius * (x_c_i - x_i_c);
float phi_i;
Vec3 omega_i;
gabor_sample (gp, c_i, rng, omega_i, phi_i);
if (x_k_i.val().length2() < gp.radius2) {
if (! gp.do_filter) {
// N.B. if determinant(gp.filter) is too small, we will
// run into numerical problems. But the filtering isn't
// needed in that case anyway, so just don't filter.
// This seems to only come up when the filter region is
// tiny.
sum += gabor_kernel (gp.weight, omega_i, phi_i, gp.a, x_k_i); // 3D
} else {
// Transform the impulse's anisotropy into tangent space
Vec3 omega_i_t;
multMatrix (gp.local, omega_i, omega_i_t);
// Slice to get a 2D kernel
Dual2<float> d_i = -dot(gp.N, x_k_i);
Dual2<float> w_i_t_s;
Vec2 omega_i_t_s;
Dual2<float> phi_i_t_s;
slice_gabor_kernel_3d (d_i, gp.weight, gp.a,
omega_i_t, phi_i,
w_i_t_s, omega_i_t_s, phi_i_t_s);
// Filter the 2D kernel
Dual2<float> w_i_t_s_f;
float a_i_t_s_f;
Vec2 omega_i_t_s_f;
Dual2<float> phi_i_t_s_f;
filter_gabor_kernel_2d (gp.filter, w_i_t_s, gp.a, omega_i_t_s, phi_i_t_s, w_i_t_s_f, a_i_t_s_f, omega_i_t_s_f, phi_i_t_s_f);
// Now evaluate the 2D filtered kernel
Dual2<Vec3> xkit;
multMatrix (gp.local, x_k_i, xkit);
Dual2<Vec2> x_k_i_t = make_Vec2 (comp(xkit,0), comp(xkit,1));
Dual2<float> gk = gabor_kernel (w_i_t_s_f, omega_i_t_s_f, phi_i_t_s_f, a_i_t_s_f, x_k_i_t); // 2D
if (! OIIO::isfinite(gk.val())) {
// Numeric failure of the filtered version. Fall
// back on the unfiltered.
gk = gabor_kernel (gp.weight, omega_i, phi_i, gp.a, x_k_i); // 3D
}
sum += gk;
}
}
}
return sum;
}