IDirectInputDevice8::SetProperty Method

Sets properties that define the device behavior. These properties include input buffer size and axis mode.

Syntax

HRESULT SetProperty(      

    REFGUID rguidProp,
    LPCDIPROPHEADER pdiph
);

Parameters

rguidProp

Reference to (C++) or address of (C) the globally unique identifier (GUID) identifying the property to be set. This can be one of the predefined values, or a pointer to a GUID that identifies the property. The following property values are predefined for an input device:

DIPROP_APPDATA

Sets the application-defined value associated with an in-game action, as a DIPROPPOINTER.

DIPROP_AUTOCENTER

Specifies whether device objects are self centering. This setting applies to the entire device, rather than to any particular object, so the dwHow member of the associated DIPROPDWORD structure must be DIPH_DEVICE.

The dwData member can be one of the following values.

DIPROPAUTOCENTER_OFF: The device should not automatically center when the user releases the device. An application that uses force feedback should disable autocentering before playing effects.

DIPROPAUTOCENTER_ON: The device should automatically center when the user releases the device.

Not all devices support the autocenter property.

DIPROP_AXISMODE

Sets the axis mode. The value being set (DIPROPAXISMODE_ABS or DIPROPAXISMODE_REL) must be specified in the dwData member of the associated DIPROPDWORD structure. See the description of the pdiph parameter for more information.

This setting applies to the entire device, so the dwHow member of the associated DIPROPDWORD structure must be set to DIPH_DEVICE.

DIPROP_BUFFERSIZE

Sets the input buffer size. The value being set must be specified in the dwData member of the associated DIPROPDWORD structure. See Remarks. This setting applies to the entire device, so the dwHow member of the associated DIPROPDWORD structure must be set to DIPH_DEVICE.

DIPROP_CALIBRATION

Predefined property that allows the application to access the information that Microsoft?DirectInput?uses to manipulate axes that require calibration. This property exists primarily for applications of the control panel type. Normal applications should not need to deal with calibration information.

You can access the calibration mode property for an axis by setting the dwHow member of the DIPROPHEADER structure to DIPH_BYID or to DIPH_BYOFFSET and setting the dwObj member to the object identifier (ID) or offset, respectively.

Control panel applications that set new calibration data must also invoke the IDirectInputJoyConfig::SendNotify method to notify other applications of the change in calibration. For more information about IDirectInputJoyConfig::SendNotify, see the Microsoft DirectX® Driver Development Kit (DDK).

DIPROP_CALIBRATIONMODE

Enables the application to specify whether DirectInput should retrieve calibrated or uncalibrated data from an axis. By default, DirectInput retrieves calibrated data.

Setting the calibration mode for the entire device is equivalent to setting it for each axis individually.

The dwData member of the DIPROPDWORD structure can be one of the following values:

DIPROPCALIBRATIONMODE_COOKED: DirectInput should return data after applying calibration information. This is the default mode.

DIPROPCALIBRATIONMODE_RAW: DirectInput should return raw, uncalibrated data. This mode is typically used only by applications of the control panel type. Note that raw data might include negative values.

Setting a device into raw mode causes the dead zone, saturation, and range settings to be ignored.

DIPROP_CPOINTS

Sets calibration points used for the adjustment of incoming raw data. The values being set must be specified as CPOINT types in the cp array of the associated DIPROPCPOINTS structure. This setting applies to individual device objects, so the dwHow member of the associated DIPROPHEADER structure must be set to either DIPH_BYID or DIPH_BYOFFSET.

DIPROP_DEADZONE

Sets the value for the dead zone of a joystick, in the range from 0 through 10,000, where 0 indicates that there is no dead zone, 5,000 indicates that the dead zone extends over 50 percent of the physical range of the axis on both sides of center, and 10,000 indicates that the entire physical range of the axis is dead. When the axis is within the dead zone, it is reported as being at the center of its range. This setting can be applied to either the entire device or to a specific axis.

DIPROP_FFGAIN

Sets the gain for the device. This setting applies to the entire device, rather than to any particular object, so the dwHow member of the associated DIPROPDWORD structure must be DIPH_DEVICE.

The dwData member contains a gain value that is applied to all effects created on the device. The value is an integer in the range from 0 through 10,000, specifying the amount by which effect magnitudes should be scaled for the device. For example, a value of 10,000 indicates that all effect magnitudes are to be taken at face value. A value of 9,000 indicates that all effect magnitudes are to be reduced to 90 percent of their nominal magnitudes.

DirectInput always checks the gain value before setting the gain property. If the gain is outside of the range (less than zero or greater than 10,000), IDirectInputDevice8::SetProperty will return DIERR_INVALIDPARAM. Otherwise, if successful, it will return DI_OK, even if the device does not support force feedback.

Setting a gain value is useful when an application wants to scale down the strength of all force-feedback effects uniformly, based on user preferences.

Unlike other properties, the gain can be set when the device is in an acquired state.

DIPROP_INSTANCENAME

This property exists for advanced applications that want to change the friendly instance name of a device (as returned in the tszInstanceName member of the DIDEVICEINSTANCE structure) to distinguish it from similar devices that are plugged in simultaneously. Most applications should have no need to change the friendly name.

This setting applies to the entire device, so the dwHow member of the associated DIPROPDWORD structure must be set to DIPH_DEVICE.

The pdiph parameter must be a pointer to the diph member of a DIPROPSTRING structure.

DIPROP_PRODUCTNAME

This property exists for advanced applications that want to change the friendly product name of a device (as returned in the tszProductName member of the DIDEVICEINSTANCE structure) to distinguish it from similar devices which are plugged in simultaneously. Most applications should have no need to change the friendly name.

This setting applies to the entire device, so the dwHow member of the associated DIPROPDWORD structure must be set to DIPH_DEVICE.

The pdiph parameter must be a pointer to the diph member of a DIPROPSTRING structure.

Setting the product name is only useful for changing the user-defined name of an analog joystick on Microsoft Windows?98,Windows 2000, and Windows Millennium Edition (Windows Me) computers. In other cases, attempting to set this property will still return DI_OK. However, the name is not stored in a location used by IDirectInputDevice8::GetProperty.

DIPROP_RANGE

Sets the range of values an object can possibly report. The minimum and maximum values are taken from the lMin and lMax members of the associated DIPROPRANGE structure.

For some devices, this is a read-only property.

You cannot set a reverse range; lMax must be greater than lMin.

DIPROP_SATURATION

Sets the value for the saturation zones of a joystick, in the range from 0 through 10,000. The saturation level is the point at which the axis is considered to be at its most extreme position. For example, if the saturation level is set to 9,500, the axis reaches the extreme of its range when it has moved 95 percent of the physical distance from its center position (or from the dead zone). This setting can be applied to either the entire device or a specific axis.

pdiph

Address of the DIPROPHEADER structure contained within the type-specific property structure.

Return Value

If the method succeeds, the return value is DI_OK or DI_PROPNOEFFECT.

If the method fails, the return value can be one of the following error values.

DIERR_INVALIDPARAM	An invalid parameter was passed to the returning function, or the object was not in a state that permitted the function to be called. This value is equal to the E_INVALIDARG standard Component Object Model (COM) return value.
DIERR_NOTINITIALIZED	The object has not been initialized.
DIERR_OBJECTNOTFOUND	The requested object does not exist.
DIERR_UNSUPPORTED	The function called is not supported at this time. This value is equal to the E_NOTIMPL standard COM return value.

Remarks

The buffer size determines the amount of data that the buffer can hold between calls to the IDirectInputDevice8::GetDeviceData method before data is lost. This value may be set to 0 to indicate that the application does not read buffered data from the device. If the buffer size in the dwData member of the DIPROPDWORD structure is too large for the device to support it, then the largest possible buffer size is set.

See Also

IDirectInputDevice8::GetProperty