A structure containing a template for a Periodic effect.
Defined in SDL_haptic.h
typedef struct SDL_HapticPeriodic
{
/* Header */
Uint16 type; /**< SDL_HAPTIC_SINE, SDL_HAPTIC_LEFTRIGHT,
SDL_HAPTIC_TRIANGLE, SDL_HAPTIC_SAWTOOTHUP or
SDL_HAPTIC_SAWTOOTHDOWN */
SDL_HapticDirection direction; /**< Direction of the effect. */
/* Replay */
Uint32 length; /**< Duration of the effect. */
Uint16 delay; /**< Delay before starting the effect. */
/* Trigger */
Uint16 button; /**< Button that triggers the effect. */
Uint16 interval; /**< How soon it can be triggered again after button. */
/* Periodic */
Uint16 period; /**< Period of the wave. */
Sint16 magnitude; /**< Peak value; if negative, equivalent to 180 degrees extra phase shift. */
Sint16 offset; /**< Mean value of the wave. */
Uint16 phase; /**< Positive phase shift given by hundredth of a degree. */
/* Envelope */
Uint16 attack_length; /**< Duration of the attack. */
Uint16 attack_level; /**< Level at the start of the attack. */
Uint16 fade_length; /**< Duration of the fade. */
Uint16 fade_level; /**< Level at the end of the fade. */
} SDL_HapticPeriodic;The struct handles the following effects:
A periodic effect consists in a wave-shaped effect that repeats itself over time. The type determines the shape of the wave and the parameters determine the dimensions of the wave.
Phase is given by hundredth of a degree meaning that giving the phase a value of 9000 will displace it 25% of its period. Here are sample values:
Examples:
SDL_HAPTIC_SINE
__ __ __ __
/ \ / \ / \ /
/ \__/ \__/ \__/
SDL_HAPTIC_SQUARE
__ __ __ __ __
| | | | | | | | | |
| |__| |__| |__| |__| |
SDL_HAPTIC_TRIANGLE
/\ /\ /\ /\ /\
/ \ / \ / \ / \ /
/ \/ \/ \/ \/
SDL_HAPTIC_SAWTOOTHUP
/| /| /| /| /| /| /|
/ | / | / | / | / | / | / |
/ |/ |/ |/ |/ |/ |/ |
SDL_HAPTIC_SAWTOOTHDOWN
\ |\ |\ |\ |\ |\ |\ |
\ | \ | \ | \ | \ | \ | \ |
\| \| \| \| \| \| \|