GLXDrawable drawabl )

PARAMETERS
dpy Specifies the connection to the X server.

drawabl Specifies a GLX drawable. Must be a GLX pixel buffer or a win‐
dow.

_param3 Specifies the events to be returned for drawabl.

DESCRIPTION
glXSelectEvent sets the GLX event mask for a GLX pixel buffer or a win‐
dow. Calling glXSelectEvent overrides any previous event mask that was
set by the client for drawabl. Note that it does not affect the event
masks that other clients may have specified for drawabl since each
client rendering to drawabl has a separate event mask for it.

Currently, only one GLX event, GLX_PBUFFER_CLOBBER_MASK, can be se‐
lected. The following data is returned to the client when a
GLX_PBUFFER_CLOBBER_MASK event occurs:

typdef struct {

int event_type; /* GLX_DAMAGED or GLX_SAVED */
int draw_type; /* GLX_WINDOW or GLX_PBUFFER */
unsigned long serial; /* # of last request processed by server */
Bool send_event; /* true if this came for SendEvent request */
Display *display; /* display the event was read from */
GLXDrawable drawable; /* i.d. of Drawable */
unsigned int buffer_mask; /* mask indicating affectedbuffers */
int x, y;
int width, height;
int count; /* if nonzero, at least this many more */
} GLXPbufferClobberEvent;
The valid bit masks used in buffer_mask are:

──────────────────────────────────────────────────────
Bitmask Corresponding Buffer
──────────────────────────────────────────────────────
GLX_FRONT_LEFT_BUFFER_BIT Front left color buffer
GLX_FRONT_RIGHT_BUFFER_BIT Front right color buffer
GLX_BACK_LEFT_BUFFER_BIT Back left color buffer
GLX_BACK_RIGHT_BUFFER_BIT Back right color buffer
GLX_AUX_BUFFERS_BIT Auxillary buffer
GLX_DEPTH_BUFFER_BIT Depth buffer
GLX_STENCIL_BUFFER_BIT Stencil buffer
GLX_ACCUM_BUFFER_BIT Accumulation buffer
──────────────────────────────────────────────────────

A single X server operation can cause several buffer clobber events to
be sent. (e.g., a single GLX pixel buffer may be damaged and cause mul‐
tiple buffer clobber events to be generated). Each event specifies one
color buffers.

For preserved GLX pixel buffers, a buffer clobber event with type
GLX_SAVED is generated whenever the contents of the GLX pixel buffer is
moved out of offscreen memory. The event(s) describes which portions of
the GLX pixel buffer were affected. Clients who receive many buffer
clobber events, referring to different save actions, should consider
freeing the GLX pixel buffer resource in order to prevent the system
from thrashing due to insufficient resources.

For an unpreserved GLXPbuffer, a buffer clobber event, with type
GLX_DAMAGED, is generated whenever a portion of the GLX pixel buffer be‐
comes invalid. The client may wish to regenerate the invalid portions of
the GLX pixel buffer.

For Windows, buffer clobber events, with type GLX_SAVED, occur whenever
an ancillary buffer, associated with the window, gets clobbered or moved
out of offscreen memory. The event contains information indicating which
color buffers and ancillary buffers-and which portions of those buffers-
were affected.

NOTES
glXSelectEvent is available only if the GLX version is 1.3 or greater.

If the GLX version is 1.1 or 1.0, the GL version must be 1.0. If the
GLX version is 1.2, then the GL version must be 1.1. If the GLX version
is 1.3, then the GL version must be 1.2.

ERRORS
GLXBadDrawable is generated if drawabl is not a valid window or a valid
GLX pixel buffer.

ASSOCIATED GETS
glXGetSelectedEvent