# Force Feedback Support

'''Include File(s):'''  [http://hg.libsdl.org/SDL/file/default/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)
 1. Open a haptic device
  a. [[SDL_HapticOpen]]() to open from index
  a. [[SDL_HapticOpenFromJoystick]]() to open from an existing joystick
 1. Create an effect ([[SDL_HapticEffect]])
 1. Upload the effect with [[SDL_HapticNewEffect]]()
 1. Run the effect with [[SDL_HapticRunEffect]]()
 1. (optional) Free the effect with [[SDL_HapticDestroyEffect]]()
 1. 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_HapticClose](SDL_HapticClose)
- [SDL_HapticCondition](SDL_HapticCondition)
- [SDL_HapticConstant](SDL_HapticConstant)
- [SDL_HapticCustom](SDL_HapticCustom)
- [SDL_HapticDestroyEffect](SDL_HapticDestroyEffect)
- [SDL_HapticDirection](SDL_HapticDirection)
- [SDL_HapticEffect](SDL_HapticEffect)
- [SDL_HapticEffectSupported](SDL_HapticEffectSupported)
- [SDL_HapticGetEffectStatus](SDL_HapticGetEffectStatus)
- [SDL_HapticIndex](SDL_HapticIndex)
- [SDL_HapticLeftRight](SDL_HapticLeftRight)
- [SDL_HapticName](SDL_HapticName)
- [SDL_HapticNewEffect](SDL_HapticNewEffect)
- [SDL_HapticNumAxes](SDL_HapticNumAxes)
- [SDL_HapticNumEffects](SDL_HapticNumEffects)
- [SDL_HapticNumEffectsPlaying](SDL_HapticNumEffectsPlaying)
- [SDL_HapticOpen](SDL_HapticOpen)
- [SDL_HapticOpened](SDL_HapticOpened)
- [SDL_HapticOpenFromJoystick](SDL_HapticOpenFromJoystick)
- [SDL_HapticOpenFromMouse](SDL_HapticOpenFromMouse)
- [SDL_HapticPause](SDL_HapticPause)
- [SDL_HapticPeriodic](SDL_HapticPeriodic)
- [SDL_HapticQuery](SDL_HapticQuery)
- [SDL_HapticRamp](SDL_HapticRamp)
- [SDL_HapticRumbleInit](SDL_HapticRumbleInit)
- [SDL_HapticRumblePlay](SDL_HapticRumblePlay)
- [SDL_HapticRumbleStop](SDL_HapticRumbleStop)
- [SDL_HapticRumbleSupported](SDL_HapticRumbleSupported)
- [SDL_HapticRunEffect](SDL_HapticRunEffect)
- [SDL_HapticSetAutocenter](SDL_HapticSetAutocenter)
- [SDL_HapticSetGain](SDL_HapticSetGain)
- [SDL_HapticStopAll](SDL_HapticStopAll)
- [SDL_HapticStopEffect](SDL_HapticStopEffect)
- [SDL_HapticUnpause](SDL_HapticUnpause)
- [SDL_HapticUpdateEffect](SDL_HapticUpdateEffect)
- [SDL_JoystickIsHaptic](SDL_JoystickIsHaptic)
- [SDL_MouseIsHaptic](SDL_MouseIsHaptic)
- [SDL_NumHaptics](SDL_NumHaptics)
<!-- END CATEGORY LIST -->
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CategoryCategory