Reference no: EM132160242
Assignment -
Illumination -
Which three components does the Phong illumination model contain? Which of them will change if one of the followings happens in a scene?
a. A light source is moved to a new location.
b. The object is moved to a new location.
c. The observer is moved to a new location.
What is the value of the specular exponent for a perfect mirror? Why?
A plane is defined by equation x + z - 2 = 0, with the diffuse reflection coefficient 0.5. A point light source with intensity 1 is located at (10, 10, 10). Calculate a diffuse reflection on the plane at point (1, 10, 1).
A point light source with intensity 1 is located at coordinates (8, 10, 10). It illuminates an origin-centered sphere with radius 2, diffuse coefficient 0.7, specular coefficient 0.2, and specular exponent 2. The ambient reflection coefficient is 0.1. The intensity of the ambient light source is 1. An observer located at the position with coordinates (10, 0, 0) is looking at a point on the sphere, along the direction [-1 0 0]. Find the point and calculate the illumination on the surface of the sphere at the point seen by the observer.
Surface mapping -
Discuss how the texture mapping, bump mapping and displacement mapping use an image to change the appearance of a surface.
With reference to Figure Q2, an image consisting of pixels 101x161 is mapped to a bilinear surface defined by P(s,t) = P1 + (P2-P1)s + (P3-P1)t + (P1-P2-P3+P4)st with P1 = (10, 30, 0), P2 = (4, 20, 0), P3 = (16, 10, 2) and P4 = (12, 5, 2). Which pixel on the image is mapped to the point with coordinates (9.8, 18, 0.8) on the surface?
With reference to Figure Q4, a displacement mapping is applied to a sphere, which creates a 3D solid object defined implicitly by: f(x, y, z) = (4 - x2 - y2 - z2)+0.1·[sin(20πx)sin(20πy)+sin(20πx)sin(20πz)+sin(20πy)sin(20πz)] ≥ 0. Find a tight sphere containing this object. What are the center and radius of the bounding sphere?
