Concerning phong shading and Gouraud shading in a 3D scene, which of the following statements are true?

(A) Gouraud shading requires more computation than phong shading.

(B) Gouraud shading linearly interpolates the color of an interior pixel from the color at the vertices.

(C) Phong shading interpolates over the normal vectors specified at the vertices.

1. A(A) and (B) only
2. B(A) and (C) only
3. C(B) and (C) only
4. D(A), (B) and (C)

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Show answer & explanation

Correct answer: C. (B) and (C) only

Explanation

Gouraud interpolates vertex colours; Phong interpolates normals and lights each pixel, so Phong costs more (A false).