czm_sunPositionColumbusView
An automatic GLSL uniform representing the sun position in Columbus view world coordinates.
Like all automatic uniforms, czm_sunPositionColumbusView does not need to be explicitly declared.
However, it can be explicitly declared when a shader is also used by other applications such
as a third-party authoring tool.
Example
// GLSL declaration uniform vec3 czm_sunPositionColumbusView;