If the option is enabled, the output is clamped to the target range. The target range is [To Min, To Max]. The option is enabled by default. The clamp option is implemented in EEVEE by linking to the `clamp_value` GLSL function. And it is implemented in Cycles using a graph expand function. Reviewers: brecht, JacquesLucke Differential Revision: https://developer.blender.org/D5477