I am struggling to understand as to why fundamentally triangles shaded through Gouraud shading and ones shaded through Phong shading look different.
From my understanding, Gouraud Shading, takes the vertices of a triangle. It calculates the color at each vertex with the help of vertex normals, and interpolates that color across the triangle per-pixel. Phong Shading calculates the normal at each vertex, and interpolates the normals across the triangle per-pixel and shades the said pixels using interpolated normals
Both involve interpolation. Why is it that interpolating normals produces a more realistic results, while interpolating the colors directly does not? What is it about the interpolation of colors that makes it less accurate?
Under the hood, isn't interpolating just a color similar to interpolating the normal and finding the color at every point? If not, intuitively how are they both different then?