Compute the intensity at the centroid of a white triangle with vertices P1, P2 and P3 using the Phong Illumination model considering the following equation: I = laka +1(kauss(N. L) +kspec (R.V)") where: P1 = (1,1,1) P2 = (0,2,1) P3 = (0,0,1) viewer position at (1,2,5) ka = 0.7, kdiri = 0.9, kspec = 0.6, n = 10 with ambient intensity = 0.1 point light intensity = 0.5 and position = (1,1,5) where both ambient and point light are white. Hint 1: Compute N first using the cross product of vertex subtractions Hint 2: Compute R using the method we studied in class What can be the result if the triangle is colored