def resample_wo(sampler, active):
""" Sample outgoing direction and pdf with cosine weighted sampling"""
d_out_local = warp.square_to_cosine_hemisphere(sampler.next_2d(active))
d_out_pdf = warp.square_to_cosine_hemisphere_pdf(d_out_local)
return d_out_local, d_out_pdf
def pdf(self, ctx, si, wo, active):
if not ctx.is_enabled(BSDFFlags.DiffuseReflection):
return Vector3f(0)
cos_theta_i = Frame3f.cos_theta(si.wi)
cos_theta_o = Frame3f.cos_theta(wo)
pdf = warp.square_to_cosine_hemisphere_pdf(wo)
return ek.select((cos_theta_i > 0.0) & (cos_theta_o > 0.0), pdf, 0.0)
def sample(self, ctx, si, sample1, sample2, active):
cos_theta_i = Frame3f.cos_theta(si.wi)
active &= cos_theta_i > 0
bs = BSDFSample3f()
bs.wo = warp.square_to_cosine_hemisphere(sample2)
bs.pdf = warp.square_to_cosine_hemisphere_pdf(bs.wo)
bs.eta = 1.0
bs.sampled_type = +BSDFFlags.DiffuseReflection
bs.sampled_component = 0
value = self.m_reflectance.eval(si, active)
return (bs, ek.select(active & (bs.pdf > 0.0), value, Vector3f(0)))
def my_pdf(p):
return square_to_cosine_hemisphere_pdf(p)
