SDL - added new SDL_JoystickCurrentPowerLevel() API that returns the battery level of the selected joystick. Currently only implemented for XInput devices, other platforms are a TODO.

CR: Sam

include/SDL_joystick.h

@@ -71,6 +71,16 @@ typedef struct {
 
 typedef Sint32 SDL_JoystickID;
 
+typedef enum
+{
+    SDL_JOYSTICK_POWER_UNKNOWN = -1,
+    SDL_JOYSTICK_POWER_EMPTY,
+    SDL_JOYSTICK_POWER_LOW,
+    SDL_JOYSTICK_POWER_MEDIUM,
+    SDL_JOYSTICK_POWER_FULL,
+    SDL_JOYSTICK_POWER_WIRED,
+    SDL_JOYSTICK_POWER_MAX
+} SDL_JoystickPowerLevel;
 
 /* Function prototypes */
 /**
@@ -242,6 +252,11 @@ extern DECLSPEC Uint8 SDLCALL SDL_JoystickGetButton(SDL_Joystick * joystick,
  */
 extern DECLSPEC void SDLCALL SDL_JoystickClose(SDL_Joystick * joystick);
 
+/**
+*  Return the battery level of this joystick
+*/
+extern DECLSPEC SDL_JoystickPowerLevel SDLCALL SDL_JoystickCurrentPowerLevel(SDL_Joystick * joystick);
+
 
 /* Ends C function definitions when using C++ */
 #ifdef __cplusplus