Global Functions, Constants, and Defined Types

Library: libgame.so

The Game Kit has just one global function, set_mouse_position(). It should be called only by an application that has control of the screen through a BWindowScreen object. Otherwise, the kit borrows constants and types defined for graphics card drivers and by other parts of the BeOS. Those that are not documented for the Interface and Support Kits are listed here.

Global Functions

set_mouse_position()

Declared in: <game/WindowScreen.h>

	void set_mouse_position(int32 x, int32 y)

Moves the cursor hot spot to (x, y) in the screen coordinate system, where x is a left-to-right index to a pixel column and y is a top-to-bottom index to a pixel row. The origin of the coordinate system is the left top pixel of the display area of the main screen.

This function should be called only while the application has a direct connection to the frame buffer through a BWindowScreen object.

Constants

Control Flags

Declared in: <add-ons/graphics/GraphicsCard.h>

B_CRT_CONTROL

B_GAMMA_CONTROL

B_FRAME_BUFFER_CONTROL

These flags report the driver's ability to control the CRT display, make gamma corrections, and permit nonstandard configurations of the frame buffer. Only the last has any meaning for the Game Kit.

See also: CardInfo()

gs_attributes

Declared in: <game/GameSoundDefs.h>

Constant	Meaning
B_GS_MAIN_GAIN	Main gain control, in decibels. The main gain doesn't support ramping.
B_GS_CD_THROUGH_GAIN	Gain on the CD through, in decibels.
B_GS_GAIN	Gain on the sound, in decibels.
B_GS_PAN	Pan position of the sound. -1.0 for far left, 0 for middle, 1.0 for far right.
B_GS_SAMPLING_RATE	Sampling rate in hertz.
B_GS_LOOPING	If the attribute's value is nonzero, the sound automatically loops. If it's 0, the sound plays through just once.
B_GS_FIRST_PRIVATE_ATTRIBU TE	Beginning of private attribute range
B_GS_FIRST_USER_ATTRIBUTE	Beginning of user attribute range.

These are the various possible game sound attributes. The range between B_GS_FIRST_PRIVATE_ATTRIBUTE and B_GS_FIRST_USER_ATTRIBUTE are reserved; if you need custom attributes, use values B_GS_FIRST_USER_ATTRIBUTE and higher.

Defined Types

frame_buffer_info

Declared in: <add-ons/graphics/GraphicsCard.h>

	typedef struct {          short bits_per_pixel ;          short bytes_per_row ;          short width ;          short height ;          short display_width ;          short display_height ;          short display_x ;          short display_y ;       } frame_buffer_info

This structure is used to report the current configuration of the frame buffer.

See also: FrameBufferInfo()

graphics_card_hook

Declared in: <add-ons/graphics/GraphicsCard.h>

	typedef void (*graphics_card_hook)(void)

This is the general type declaration for a graphics card hook function. Specific hook functions will in fact declare various sets of arguments and all return a status_t error code rather than void.

See also: CardHookAt(),  "Graphics Card Hook Functions" on page18

graphics_card_info

Declared in: <add-ons/graphics/GraphicsCard.h>

	typedef struct {          short version;          short id;          void *frame_buffer;          char rgba_order[4];          short flags;          short bits_per_pixel;          short bytes_per_row;          short width;          short height;       } graphics_card_info

Drivers use this structure to supply information about themselves and the current configuration of the frame buffer to the Application Server and the BWindowScreen class.

See also: CardInfo()

gs_attribute

Declared in: <game/GameSoundDefs.h>

	struct gs_attribute {          int32 attribute;          bigtime_t duration;          float value;          uint32 flags;       };

Defines an attribute. An attribute consists of an attribute number from gs_attributes, a duration indicating the period of time, in microseconds, over which the attribute's change takes effect, and a target value. Additional flags can be specified for the attribute as well; these vary depending on the attribute.

Currently, there are no flags defined for any of the predefined attributes.

gs_attribute_info

Declared in: <game/GameSoundDefs.h>

	struct gs_attribute_info {          int32 attribute ;          float granularity ;          float minimum ;          float maximum ;       };

Describes the possible values the attribute can take. The granularity field indicates how finely the value of the attribute can be controlled, and minimum and maximum specify the minimum and maximum values the attribute can take on.

gs_audio_format

Declared in: <game/GameSoundDefs.h>

	struct gs_audio_format {          enum format {             B_GS_U8 = 0x11,             B_GS_S16 = 0x2,             B_GS_F = 0x24,             B_GS_S32 = 0x4          };          float frame_rate;          uint32 channel_count;          uint32 format;          uint32 byte_order;          size_t buffer_size;       };

This structure describes the format of a game sound. The format enum lists the possible sound sample formats supported by the Game Kit:

Constant	Meaning
B_GS_U8	Unsigned 8-bit integer.
B_GS_S16	Signed 16-bit integer.
B_GS_F	Floating-point.
B_GS_S32	Signed 32-bit integer.

• The frame_rate indicates how many frames per second of audio should be played.

• The channel_count field indicates the number of audio channels the sound uses.

• The format field, which specifies the format of the audio data to be played must be one of the values declared in the format enum.

• The byte_order field specifies the byte order of the sound to be played.

• The buffer_size is used to specify how large the audio buffers used to play the sound should be. You can specify zero if you want the Game Kit to determine an appropriate size for you.

gs_id

Declared in: <game/GameSoundDefs.h>

	typedef int32 gs_id;

This type is used for game sound ID numbers.