title: Missing methods and constants in OpenGL ES 2.0 headers
body: <p>I'm starting to learn to OpenGL for using it with iOS. I'm wondering why methods like <code>glMatrixMode</code> or constants like <code>GL_PROJECTION</code> are there in <code>&lt;OpenGLES/ES1/gl.h&gt;</code>, but not in <code>&lt;OpenGLES/ES2/gl.h&gt;</code>. Why? Are you enforced to write your own shaders when using OpenGL ES 2.0 instead of 1.1?</p>