Add lighting to Program 10.4, so that the surface structure of the height-mapped terrain is further exposed.

Program 10.4

#version 430 layout (location=0) in vec3 vertPos; layout (location=1) in vec2 texCoord; layout (location=2) in vec3 vertNormal; out vec2 tc; uniform mat4 mv_matrix; uniform mat4 p_matrix;