As per page 32 and page 71 of the GLSL ES 3.00.4 specification, function overloading is allowed as long as the function parameters are different. Currently your shader compiler doesn't allow function overloading. I have just hit this issue and want to bring it to your attention.
GLSL ES 3 Function overloading doesn't work.
Posted: Tue, 2013-06-18 07:45