def sample_f(self, shading_point):
w = shading_point.normal
# jitter the up vector
v = Vector(0.0024, 1.0, 0.0081).cross(w)
v = v.normalize()
u = v.cross(w)
sample_point = self.sampler.sample_hemisphere()
wi = sample_point.x * u + sample_point.y * v + sample_point.z * w
wi = wi.normalize()
pdf = shading_point.normal * wi / math.pi
color = self.surface.get_color(shading_point)
return pdf, wi, (self.kd * color / math.pi)
class AreaLight(Light):
def __init__(self, shape, cast_shadow):
self.shape = shape
self.cast_shadow = cast_shadow
self.sample = Vector(0.0, 0.0, 0.0)
self.light_normal = Vector(0.0, 0.0, 0.0)
self.wi = Vector(0.0, 0.0, 0.0)
def get_direction(self, shading_point):
self.sample = self.shape.sample()
self.light_normal = self.shape.normal
self.wi = self.sample - shading_point.hit_point
self.wi = self.wi.normalize()
return -1.0 * self.wi
def in_shadow(self, ray, shading_point):
ts = (self.sample - ray.origin) * ray.direction
for shape in shading_point.scene.shapes:
if shape.shadow_hit(ray) and shape.shadow_t < ts:
return True
return False
def L(self):
ndotd = -1.0 * self.wi * self.light_normal
if ndotd > 0.0:
return self.shape.material.Le()
else:
return Color(0.0, 0.0, 0.0)
def G(self, shading_point):
ndotd = -1.0 * self.light_normal * self.wi
d2 = self.sample.distance(shading_point.hit_point)
d2 = d2 * d2
return ndotd / d2
def pdf(self, shading_point):
return self.shape.pdf()