= Force Feedback Support =

'''Include File(s):'''  [https://github.com/libsdl-org/SDL/blob/SDL2/include/SDL_haptic.h SDL_haptic.h]


== Introduction ==

The SDL haptic subsystem allows you to control haptic (force feedback) devices.

The basic usage is as follows:

 1. Initialize the subsystem (SDL_INIT_HAPTIC)
 2. Open a haptic device
  a. [[SDL_HapticOpen]]() to open from index
  b. [[SDL_HapticOpenFromJoystick]]() to open from an existing joystick
 3. Create an effect ([[SDL_HapticEffect]])
 4. Upload the effect with [[SDL_HapticNewEffect]]()
 5. Run the effect with [[SDL_HapticRunEffect]]()
 6. (optional) Free the effect with [[SDL_HapticDestroyEffect]]()
 7. Close the haptic device with [[SDL_HapticClose]]()

== Code Examples ==
Simple rumble example:
<syntaxhighlight lang='c++'>
SDL_Haptic *haptic;

// Open the device
haptic = SDL_HapticOpen( 0 );
if (haptic == NULL)
   return -1;

// Initialize simple rumble
if (SDL_HapticRumbleInit( haptic ) != 0)
   return -1;

// Play effect at 50% strength for 2 seconds
if (SDL_HapticRumblePlay( haptic, 0.5, 2000 ) != 0)
   return -1;
SDL_Delay( 2000 );

// Clean up
SDL_HapticClose( haptic );
</syntaxhighlight>

Complete example:
<syntaxhighlight lang='c++'>
int test_haptic( SDL_Joystick * joystick ) {
 SDL_Haptic *haptic;
 SDL_HapticEffect effect;
 int effect_id;

 // Open the device
 haptic = SDL_HapticOpenFromJoystick( joystick );
 if (haptic == NULL) return -1; // Most likely joystick isn't haptic

 // See if it can do sine waves
 if ((SDL_HapticQuery(haptic) & SDL_HAPTIC_SINE)==0) {
  SDL_HapticClose(haptic); // No sine effect
  return -1;
 }

 // Create the effect
 SDL_memset( &effect, 0, sizeof(SDL_HapticEffect) ); // 0 is safe default
 effect.type = SDL_HAPTIC_SINE;
 effect.periodic.direction.type = SDL_HAPTIC_POLAR; // Polar coordinates
 effect.periodic.direction.dir[0] = 18000; // Force comes from south
 effect.periodic.period = 1000; // 1000 ms
 effect.periodic.magnitude = 20000; // 20000/32767 strength
 effect.periodic.length = 5000; // 5 seconds long
 effect.periodic.attack_length = 1000; // Takes 1 second to get max strength
 effect.periodic.fade_length = 1000; // Takes 1 second to fade away

 // Upload the effect
 effect_id = SDL_HapticNewEffect( haptic, &effect );

 // Test the effect
 SDL_HapticRunEffect( haptic, effect_id, 1 );
 SDL_Delay( 5000); // Wait for the effect to finish

 // We destroy the effect, although closing the device also does this
 SDL_HapticDestroyEffect( haptic, effect_id );

 // Close the device
 SDL_HapticClose(haptic);

 return 0; // Success
}
</syntaxhighlight>
You can find more information in this blog by Edgar Simo Serra: [http://bobbens.dyndns.org/journal/2010/sdl_haptic/ SDL Haptic In Depth]([https://web.archive.org/web/20130728040700/http://bobbens.dyndns.org/journal/2010/sdl_haptic/ Archive])


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<!-- #== Enumerations == -->
<!-- #<<FullSearchCached(category:CategoryEnum Category##### -title:SGEnumerations)>> -->

== Structures ==
<<FullSearchCached(category:CategoryStruct CategoryForceFeedback -title:SGStructures)>>

== Functions ==
<<FullSearchCached(category:CategoryForceFeedback -CategoryEnum -CategoryStruct -title:SGFunctions)>>

<!-- BEGIN CATEGORY LIST -->
* [[SDL_HapticCondition]]
* [[SDL_HapticConstant]]
* [[SDL_HapticCustom]]
* [[SDL_HapticDirection]]
* [[SDL_HapticEffect]]
* [[SDL_HapticLeftRight]]
* [[SDL_HapticPeriodic]]
* [[SDL_HapticRamp]]
<!-- END CATEGORY LIST -->
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CategoryCategory