def colorAt(self, objHit, hitPos, hitNormal):
material = objHit.material
objColor = material.colorAt(hitPos)
toCamera = self.camera.subVector(hitPos)
specularCoef = 80
color = Color(0,0,0).multiplyVector(material.ambient)
for light in self.lights:
toTheLight = Ray(hitPos, light.pos.subVector(hitPos))
# Diffuse shading (Lambert)
mtrl1 = objColor.multiplyVector(material.diffuse)
mtrl2 = mtrl1.multiplyVector(max(hitNormal.dotProduct(toTheLight.direction), 0))
color = color.addVector(mtrl2)
# Specular shading (Blinn-Phong)
halfVector = (toTheLight.direction.addVector(toCamera)).normalizeVector()
mtrl3 = light.color.multiplyVector(material.specular)
mtrl4 = mtrl3.multiplyVector(max(hitNormal.dotProduct(halfVector), 0) ** specularCoef)
color = color.addVector(mtrl4)
return color
def traceRay(self, ray, depth=0, maxDepth= 5):
color = Color()
# Find the nearest object hit by the ray in the scene
distHit, objHit = self.findNearest(ray)
if objHit is None:
return color
hitPos = ray.direction.multiplyVector(distHit).addVector(ray.origin)
hitNormal = objHit.surfaceNormal(hitPos)
color = color.addVector(self.colorAt(objHit, hitPos, hitNormal))
if depth < maxDepth:
#The value of 0.0001 is the minimum displace
newRayPos = hitNormal.multiplyVector(0.0001).addVector(hitPos)
"""Then we implement the reflection formula
R = V - 2(V . N) * N
where,
R is the normalized reflected ray,
L is a direction unit vector of the ray to be reflected,
N is the direction unit vector normal to the surface the ray stroke
"""
newRayDirection = ray.direction.subVector(hitNormal.multiplyVector(ray.direction.dotProduct(hitNormal) * 2))
newRay = Ray(newRayPos, newRayDirection)
#Attenuation phase
color = color.addVector((self.traceRay(newRay, depth+1).multiplyVector(objHit.material.reflection)))
return color
