An extract on #ciltbakim
Gouraud shading is considered superior to flat shading and requires significantly less processing than Phong shading, but usually results in a faceted look.
In comparison to Phong shading, Gouraud shading's strength and weakness lies in its interpolation. If a mesh covers more pixels in screen space than it has vertices, interpolating colour values from samples of expensive lighting calculations at vertices is less processor intensive than performing the lighting calculation for each pixel as in Phong shading. However, highly localized lighting effects (such as specular highlights, e.g. the glint of reflected light on the surface of an apple) will not be rendered correctly, and if a highlight lies in the middle of a polygon, but does not spread to the polygon's vertex, it will not be apparent in a Gouraud rendering; conversely, if a highlight occurs at the vertex of a polygon, it will be rendered correctly at this vertex (as this is where the lighting model is applied), but will be spread unnaturally across all neighboring polygons via the interpolation method.
The problem is easily spotted in a rendering which ought to have a specular highlight moving smoothly across the surface of a model as it rotates. Gouraud shading will instead produce a highlight continuously fading in and out across neighboring portions of the model, peaking in intensity when the intended specular highlight passes over a vertex of the model. While this problem can be fixed by increasing the density of vertices in the object, at some point the diminishing returns of this approach will favour switching to a more detailed shading model.
In 1970, Emerson left the Nice and formed Emerson, Lake & Palmer (ELP) with bassist Greg Lake from King Crimson and drummer Carl Palmer from Atomic Rooster. Within a few months, the band played its first shows and recorded its first album, having quickly obtained a record deal with Atlantic Records. ELP became popular immediately after their 1970 Isle of Wight Festival performance, and continued to tour regularly throughout the 1970s. Not all were impressed, with BBC Radio 1 DJ John Peel describing their Isle of Wight set as "[a] waste of talent and electricity." Their set, with a half-million onlookers, involved "annihilating their instruments in a classical-rock blitz" and firing cannons from the stage. Recalling the gig in a 2002 interview, Emerson said: "We tried the cannons out on a field near Heathrow airport ... They seemed harmless enough. Today we would have been arrested as terrorists."