Add RGUI.

Home.md

@@ -3,6 +3,7 @@ Welcome to the RetroArch wiki!
 Here you can find information about RetroArch, FAQs, compilation guides, etc ...
 
 [[FAQ]]<br/>
+[[RGUI]]<br/>
 [[Compilation guide (Linux)]]<br/>
 [[Compilation guide (Windows)]]<br/>
 [[Compilation guide (OS X)]]<br/>

RGUI.md

@@ -0,0 +1,55 @@
+## Purpose
+
+RGUI is a simple built-in GUI for RetroArch. It is designed to allow
+the console experience, where everything is controlled from a joypad.
+It focuses on being useful, and particularily flashy.
+It was introduced in 0.9.9-wip1 on PC platforms.
+It is also present on mobile platforms where RetroArch is supported.
+
+From command-line, RetroArch has a simple lifecycle, you start up a game and exit. Starting a new game, you would need to start RetroArch again.
+RGUI adds a layer on top of this model.
+
+### Features
+
+![Alt RGUI startup screen](/rgui/rgui.png)
+
+While RGUI cannot configure absolutely everything,
+it can do the most common things you would want to do while using RetroArch.
+
+- Selecting libretro core
+- Load a game
+- Tweak per-libretro core options
+- Load game from history (previous games played)
+- Save/load savestates
+- Configure shaders
+- Configure aspect ratios
+- Configure integer scale
+- Toggle fullscreen
+- Swap disk images (needed for PlayStation, see notes below!)
+- Take screenshots
+- Enable/disable real-time rewind 
+- Simple input configuration
+- Mute/unmute audio
+- Exit RetroArch (yes, sadly :p)
+
+### Entering the menu
+
+By default on PC, the F1 button will enter the menu.
+To exit the menu, use F1 or `Resume Game`.
+To start immediately in RGUI without any game or core loaded, use
+the `--menu` command line option. As a special case, if no arguments are received, it is treated the same as running `retroarch --menu`.
+
+Menu toggle button can be mapped to joypad as well, see option `input_menu_toggle` option in `retroarch.cfg`.
+
+### Navigating the menu
+
+RGUI is controlled like any other libretro core.
+Regular input binds will apply, and binds here are defined in terms of the RetroPad, RetroArch's joypad abstraction.
+
+- A button (Default PC: X): Accept/OK
+- B button (Default PC: Z): Back/Cancel
+- Start (Default PC: Return): Go to main settings menu
+- Select (Default PC: Right shift): Set a setting to default
+- Up/Down D-pad (Default PC: Up/Down keys): Browse settings/files
+- Left/Right D-pad (Default PC: Left/Right keys): Toggle settings, or browse several items at once in file browser.
+