PrestaShop as a 3-tier architecture (MVC)

[vpanugaling]

If PrestaShop is based on a 3-tier architecture (MVC), what is the name of the controller that renders the .tpl files inside a theme?

e.g myProject/themes/default("Default theme in Prestashop")/(.tpl files)

 

or maybe where I can find the location of the controller that renders the .tpl files? So that I can add more smarty tags 

//Assume this file is the controller that renders the .tpl files in a theme

//I got this code for converting a php value to a smarty tag in creating a module http://doc.prestashop.com/display/PS15/Creating+a+PrestaShop+module

$this->context->smarty->assign(array(

    'Hello' => "Hello",

    'World' => "World",

    'another_smarty_tag' => "Im another smarty tag"

));