The SDL haptic subsystem manages haptic (force feedback) devices.
The basic usage is as follows:
Simple rumble example:
SDL_Haptic *haptic = NULL;
// Open the device
SDL_HapticID *haptics = SDL_GetHaptics(NULL);
if (haptics) {
haptic = SDL_OpenHaptic(haptics[0]);
SDL_free(haptics);
}
if (haptic == NULL)
return -1;
// Initialize simple rumble
if (SDL_InitHapticRumble(haptic) != 0)
return -1;
// Play effect at 50% strength for 2 seconds
if (SDL_PlayHapticRumble(haptic, 0.5, 2000) != 0)
return -1;
SDL_Delay(2000);
// Clean up
SDL_CloseHaptic(haptic);Complete example:
int test_haptic(SDL_Joystick *joystick)
{
SDL_Haptic *haptic;
SDL_HapticEffect effect;
int effect_id;
// Open the device
haptic = SDL_OpenHapticFromJoystick(joystick);
if (haptic == NULL) return -1; // Most likely joystick isn't haptic
// See if it can do sine waves
if ((SDL_GetHapticFeatures(haptic) & SDL_HAPTIC_SINE)==0) {
SDL_CloseHaptic(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_CreateHapticEffect(haptic, &effect);
// Test the effect
SDL_RunHapticEffect(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_DestroyHapticEffect(haptic, effect_id);
// Close the device
SDL_CloseHaptic(haptic);
return 0; // Success
}Note that the SDL haptic subsystem is not thread-safe.