Joystick
Capabilities
Joysticks can
support two- or three-axis movement and up to four buttons. Joysticks also
support different ranges of motion and polling frequencies. The
range of motion is the distance a joystick handle can move from its resting
position to the position farthest from its resting position. The polling
frequency is the time interval between joystick queries.
Joystick
drivers can support either one or two joysticks. You can determine the number
of joysticks supported by a joystick driver by using the joyGetNumDevs function. This function
returns an unsigned integer that contains the number of supported joysticks or
zero if there is no joystick support. The return value does not indicate the
number of joysticks attached to the system.
You can
determine if a joystick is attached to the system by using the joyGetPos function. This function
returns JOYERR_NOERROR if the specified device is attached. Otherwise , it
returns JOYERR_UNPLUGGED.
Each joystick
has several capabilities that are available to your application. You can
retrieve the capabilities of a joystick by using the joyGetDevCaps function. This function
fills a JOYCAPS
structure with joystick capabilities such as the minimum and maximum values for
its coordinate system, the number of buttons on the joystick, and the minimum
and maximum polling frequencies.