In chapter 12, I’ve got the terrain drawing, but it’s all green; it’s as if, when calling mix(), aPosition.y were just 0. (When I replace aPosition.y with 1.0, everything comes out grey, so I know mix() is doing something right.)
I tried changing aPosition.y to .x and .z; same results. But, of course, aPosition is used to generate gl_Position later on in the shader, so it can’t just be (0,0,0). Any ideas?