Contains type-specific information for effects that are marked as DIEFT_PERIODIC.
The structure describes a periodic effect.
A pointer to a single DIPERIODIC structure for an effect is passed in the lpvTypeSpecificParams member of the DIEFFECT structure.
typedef struct DIPERIODIC {
DWORD dwMagnitude;
LONG lOffset;
DWORD dwPhase;
DWORD dwPeriod;
} DIPERIODIC, *LPDIPERIODIC;
A device driver cannot provide support for all values in the dwPhase member. In this case, the value is rounded off to the nearest supported value.