I’m writing a shader for the GLSL 1.2 but at the same time I want my shader to be forward compatible so that it does not use built-in attributes and uniforms, such as gl_Vertex, glModelViewProjectionMatrix.
Is it possible to define my own, for example instead of using gl_vertex,
attribute vec4 position
or in vec4 position
Does this has any performance implication when used in shader version 1.2?