REFRESH_SEGMENT(3G)

NAME

refresh_segment, refresh_segment_hsr − display specified segment network on associated graphics display device

SYNOPSIS

C Syntax:

void refresh_segment(fildes, segno)
int fildes, segno;

void refresh_segment_hsr(fildes, segno)
int fildes, segno;

FORTRAN77 Syntax:

subroutine refresh_segment(fildes, segno)
integer*4 fildes, segno

subroutine refresh_segment_hsr(fildes, segno)
integer*4 fildes, segno

Pascal Syntax:

procedure refresh_segment(fildes, segno:integer);

procedure refresh_segment_hsr(fildes, segno:integer);

DESCRIPTION

Input Parameters

fildes Integer file descriptor returned by gopen when an I/O path to a graphics output device is opened.

segno Name of the segment from which to begin traversal.

Discussion

Refresh_segment displays the specified segment network on its associated graphics display device.

Refresh_segment_hsr displays the specified segment network on the associated graphics display device, removing hidden surfaces. For correct results from strip-zbuffer hidden-surface removal, the specified segment network should represent the complete image being displayed. Hidden surface removal must be enabled before making this call (see hidden_surface(3G)). This call applies appropriate zbuffer switching (see zbuffer_switch(3G)).

If a segment is open on graphics display device fildes, the segment is, in effect, closed during traversal then re-opened when display traversal is complete. This prevents new elements from being entered into an open segment as a result of refresh operations.

Set_traversal_depth(3G) can be used to limit the traversal depth. The default maximum traversal depth limits traversal processing to 42 segment-referencing elements (i.e., call_segment, execute_segment, cond_call_segment or cond_execute_segment). If traversal of one of these elements would exceed the maximum traversal depth, a warning is generated and the element is not traversed.

Segment network traversal can also be limited by display traversal control elements (see set_disp_traversal_control(3G)).

Output from the display traversal process is subject to buffering (see buffer_mode(3G)). If buffering is enabled, output from the display traversal process not not be displayed until the buffer is flushed. Calling make_picture_current(3G) will ensure that the buffers have been flushed.

ERRORS

1 Graphics device is not initialized for this operation.

39 Specified segment does not exist.

1042 Warning: Traversal attempted beyond specified maximum traversal depth.

HARDWARE DEPENDENCIES

For bit-mapped displays, display traversal performance can be improved by using traversal_lock(3G). This call gains exclusive access to the display during display traversal, postponing all other display updates (such as printing in terminal emulator windows) while display traversal is in progress.

Museum

Related Articles