REFRESH_SEGMENT(3G)

NAME

refresh_segment − display specified segment network on associated graphics display device

SYNOPSIS

C Syntax:

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

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

FORTRAN77 Syntax:

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

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

Pascal Syntax:

procedure refresh_segment(devdes,segno:integer);

procedure refresh_segment_hsr(devdes,segno:integer);

DESCRIPTION

Input Parameters

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

If there is no open segment in the display list devdes, an error is generated.

Set_traversal_depth(3G) can be used to limit the traversal depth. The default maximum traversal depth limits traversal processing to 42 call_segment elements. If a call_segment element would exceed the maximum traversal depth, a warning is generated and the call_segment 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 may not be displayed until the buffer is flushed. Calling make_picture_current(3G) will make sure 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.

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