czm_entireFrustum

An automatic GLSL uniform containing the near distance (x) and the far distance (y) of the frustum defined by the camera. This is the largest possible frustum, not an individual frustum used for mult-frustum rendering.

Like all automatic uniforms, czm_entireFrustum 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.

// GLSL declaration
uniform vec2 czm_entireFrustum;

// Example
float frustumLength = czm_entireFrustum.y - czm_entireFrustum.x;