public void enableVertexAttribute (String name) {
GL20 gl = Gdx.graphics.getGL20();
checkManaged();
int location = fetchAttributeLocation(name);
if (location == -1) return;
gl.glEnableVertexAttribArray(location);
}
private void checkManaged () {
if (invalidated) {
compileShaders(vertexShaderSource, fragmentShaderSource);