def brdf_remap(wo: 'geo.Vector', wi: 'geo.Vector') -> 'geo.Point':
"""
Mapping regularly sampled BRDF
using Marschner, 1998
"""
dphi = geo.spherical_phi(wi) - geo.spherical_phi(wo)
if dphi < 0.:
dphi += 2. * PI
if dphi > 2. * PI:
dphi -= 2. * PI
if dphi > PI:
dphi = 2. * PI - dphi
return geo.Point(
sin_theta(wi) * sin_theta(wo), dphi * INV_PI,
cos_theta(wi) * cos_theta(wo))
def test_spherical(self, theta, phi):
st = np.sin(theta)
ct = np.cos(theta)
v = geo.spherical_direction(st, ct, phi)
theta_ret = geo.spherical_theta(v)
phi_ret = geo.spherical_phi(v)
assert_almost_eq(theta, theta_ret)
assert_almost_eq(phi, phi_ret)
def pdf(self, p: 'geo.Point', w: 'geo.Vector') -> FLOAT: wi = self.w2l(w) theta = geo.spherical_theta(wi) phi = geo.spherical_phi(wi) st = np.sin(theta) if st == 0.: return 0. return self.dist.pdf(phi * INV_2PI, theta * INV_PI / (2. * PI * PI * st))
def __sphere(self, p: 'geo.Point') -> [FLOAT]:
"""
Spherical Mapping for single
point. Returns list
[s, t].
"""
v = geo.normalize(self.w2t(p) - geo.Point(0., 0., 0.))
theta = geo.spherical_theta(v)
phi = geo.spherical_phi(v)
return [theta * INV_PI, phi * INV_2PI]
def __scale(self, w: 'geo.Vector') -> 'Spectrum': """ __scale() Utility method to scale the amount of light projected in the given direction. Assume the scale texture is encoded using spherical coordinates. """ if self.MIPMap is None: return Spectrum(1.) wp = geo.normalize(self.w2l(w)) wp.z, wp.y = wp.y, wp.z theta = geo.spherical_theta(wp) phi = geo.spherical_phi(wp) s = phi * INV_2PI t = theta * INV_PI return Spectrum(self.projMap.look_up([s, t]), SpectrumType.ILLUMINANT)
def le(self, rd: 'geo.RayDifferential') -> 'Spectrum': wh = geo.normalize(self.w2l(rd.d)) s = geo.spherical_phi(wh) * INV_2PI t = geo.spherical_theta(wh) * INV_PI return Spectrum.from_rgb(self.radMap.look_up(s, t), SpectrumType.ILLUMINANT)