SDL2 rumble patch

--- old/Joystick_SDL.cpp    2013-08-31 23:33:41.000000000 +0200
+++ new/Joystick_SDL.cpp    2015-09-08 10:58:41.000000000 +0200
@@ -31,11 +31,14 @@
  ~Joystick_SDL();

  void UpdateInternal(void);
+
+ virtual void SetRumble(uint8 weak_intensity, uint8 strong_intensity);

  virtual unsigned HatToButtonCompat(unsigned hat);

  private:
  SDL_Joystick *sdl_joy;
+ SDL_Haptic *sdl_haptic;
  unsigned sdl_num_axes;
  unsigned sdl_num_hats;
  unsigned sdl_num_balls;
@@ -47,6 +50,32 @@
  return(sdl_num_buttons + (hat * 4));
 }

+void Joystick_SDL::SetRumble(uint8 weak_intensity, uint8 strong_intensity)
+{
+ if (sdl_haptic == NULL) {
+  return;
+ }
+
+ static int effectID = -1;
+
+ float intensity = 0.3 * weak_intensity + 0.7 * strong_intensity;
+
+ if (effectID != -1) {
+  SDL_HapticDestroyEffect(sdl_haptic, effectID);
+  effectID = -1;
+ }
+
+ if (intensity > 0) {
+  SDL_HapticEffect effect;
+  memset( &effect, 0, sizeof(SDL_HapticEffect) );
+  effect.type = SDL_HAPTIC_CONSTANT;
+  effect.constant.length = SDL_HAPTIC_INFINITY;
+  effect.constant.level = intensity / 255.0 * 32767;
+  effectID = SDL_HapticNewEffect(sdl_haptic, &effect);
+  SDL_HapticRunEffect(sdl_haptic, effectID, SDL_HAPTIC_INFINITY);
+ }
+}
+
 Joystick_SDL::Joystick_SDL(unsigned index) : sdl_joy(NULL)
 {
  sdl_joy = SDL_JoystickOpen(index);
@@ -72,10 +101,21 @@
  axis_state.resize(num_axes);
  rel_axis_state.resize(num_rel_axes);
  button_state.resize(num_buttons);
+
+ sdl_haptic = SDL_HapticOpenFromJoystick(sdl_joy);
+ if (sdl_haptic != NULL && (SDL_HapticQuery(sdl_haptic) & SDL_HAPTIC_CONSTANT)) {
+  MDFNI_printf("Rumble supported by: %s", name);
+ } else {
+  sdl_haptic = NULL;
+ }
 }

 Joystick_SDL::~Joystick_SDL()
 {
+ if (sdl_haptic) {
+  SDL_HapticClose(sdl_haptic);
+  sdl_haptic = NULL;
+ }
  if(sdl_joy)
  {
   SDL_JoystickClose(sdl_joy);
@@ -136,7 +176,7 @@

 JoystickDriver_SDL::JoystickDriver_SDL()
 {
- SDL_InitSubSystem(SDL_INIT_JOYSTICK);
+ SDL_InitSubSystem(SDL_INIT_JOYSTICK | SDL_INIT_HAPTIC);

  for(int n = 0; n < SDL_NumJoysticks(); n++)
  {