glXSelectEvent — select GLX events for a window or a GLX pixel buffer
void glXSelectEvent( | Display * | dpy, |
| GLXDrawable | draw, | |
| unsigned long | event_mask); |
dpySpecifies the connection to the X server.
drawSpecifies a GLX drawable. Must be a GLX pixel buffer or a window.
event_mask
Specifies the events to be returned for draw.
glXSelectEvent sets the GLX event mask for a GLX pixel buffer or a window.
Calling glXSelectEvent overrides any previous event mask that was
set by the client for draw. Note that it does not affect the
event masks that other clients may have specified for draw since
each client rendering to draw has a separate event mask for it.
Currently, only one GLX event, GLX_PBUFFER_CLOBBER_MASK,
can be selected. The following data is returned to the client when a
GLX_PBUFFER_CLOBBER_MASK event occurs:
typedef 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 affected buffers */ |
| 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
| Auxiliary 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 multiple buffer clobber events to be generated). Each event specifies one region of the GLX drawable that was affected by the X Server operation. The buffer_mask field indicates which color buffers and ancillary buffers were affected. All the buffer clobber events generated by a single X server action are guaranteed to be contiguous in the event queue. The conditions under which this event is generated and the event_type varies, depending on the type of the GLX drawable.
When the GLX_AUX_BUFFERS_BIT is set in buffer_mask, then
aux_buffer is set to indicate which buffer was affected. If more
than one aux buffer was affected, then additional events are
generated as part of the same contiguous event group. Each
additional event will have only the GLX_AUX_BUFFERS_BIT set in
buffer_mask, and the aux_buffer field will be set
appropriately. For nonstereo drawables,
GLX_FRONT_LEFT_BUFFER_BIT and GLX_BACK_LEFT_BUFFER_BIT are
used to specify the front and back 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
becomes 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 off-screen memory. The event contains information
indicating which color buffers and ancillary buffers\(emand which portions
of those buffers\(emwere affected.
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.
Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.