IDirectInputEffect::GetParameters Method

Articolo
09/10/2011

Retrieves information about an effect.

Syntax

HRESULT GetParameters(
         LPDIEFFECT peff,
         DWORD dwFlags
)

Parameters

peff
Address of a DIEFFECT structure that receives effect information. The dwSize member must be filled in by the application before calling this method.
dwFlags
Flags that specify which parts of the effect information are to be retrieved. The value can be 0 or one or more of the following constants:
- DIEP_ALLPARAMS
  The union of all other DIEP_* flags, indicating that all members of the DIEFFECT structure are being requested.
- DIEP_ALLPARAMS_DX5
  The union of all other DIEP_* flags except the DIEP_STARTDELAY flag.
- DIEP_AXES
  The cAxes and rgdwAxes members should receive data. The cAxes member on entry contains the size (in DWORD) of the buffer pointed to by the rgdwAxes member. If the buffer is too small, the method returns DIERR_MOREDATA and sets cAxes to the necessary size of the buffer.
- DIEP_DIRECTION
  The cAxes and rglDirection members should receive data. The cAxes member on entry contains the size (in DWORD) of the buffer pointed to by the rglDirection member. If the buffer is too small, the IDirectInputEffect::GetParameters method returns DIERR_MOREDATA and sets cAxes to the necessary size of the buffer. The dwFlags member must include at least one of the coordinate system flags (DIEFF_CARTESIAN, DIEFF_POLAR, or DIEFF_SPHERICAL). DirectInput returns the direction of the effect in one of the coordinate systems you specified, converting between coordinate systems as necessary. On exit, exactly one of the coordinate system flags is set in the dwFlags member, indicating which coordinate system DirectInput used. In particular, passing all three coordinate system flags retrieves the coordinates in exactly the same format in which they were set.
- DIEP_DURATION
  The dwDuration member should receive data.
- DIEP_ENVELOPE
  The lpEnvelope member points to a DIENVELOPE structure that should receive data. If the effect does not have an envelope associated with it, the lpEnvelope member is set to NULL.
- DIEP_GAIN
  The dwGain member should receive data.
- DIEP_SAMPLEPERIOD
  The dwSamplePeriod member should receive data.
- DIEP_STARTDELAY
  The dwStartDelay member should receive data.
- DIEP_TRIGGERBUTTON
  The dwTriggerButton member should receive data.
- DIEP_TRIGGERREPEATINTERVAL
  The dwTriggerRepeatInterval member should receive data.
- DIEP_TYPESPECIFICPARAMS
  The lpvTypeSpecificParams member points to a buffer whose size is specified by the cbTypeSpecificParams member. On return, the buffer is filled in with the type-specific data associated with the effect, and the cbTypeSpecificParams member contains the number of bytes copied. If the buffer supplied by the application is too small to contain all the type-specific data, the method returns DIERR_MOREDATA, and the cbTypeSpecificParams member contains the required size of the buffer in bytes.

Return Value

If the method succeeds, the return value is DI_OK. If the method fails, the return value can be one of the following error values: DIERR_INVALIDPARAM, DIERR_MOREDATA, DIERR_NOTINITIALIZED.

Remarks

Common errors resulting in a DIERR_INVALIDPARAM error include not setting the dwSize member of the DIEFFECT structure, passing invalid flags, or not setting up the members in the DIEFFECT structure properly in preparation for receiving the effect information. For example, if information is to be retrieved in the dwTriggerButton member, the dwFlags member must be set to either DIEFF_OBJECTIDS or DIEFF_OBJECTOFFSETS so that DirectInput knows how to describe the button.

Requirements

Header: Declared in dinput.h.

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