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The graPHIGS Programming Interface: ISO PHIGS Subroutine Reference



Use Set HLHSR Identifier to insert a Set HLHSR Identifier structure element into the open structure following the element pointer or replace the element pointed at by the element pointer with a Set HLHSR Identifier structure element, depending on the current edit mode. During structure traversal, the graPHIGS API sets the current Hidden Line/Hidden Surface Removal (HLHSR) identifier entry of the graPHIGS traversal state list to the specified parameter.

The application uses this value when creating subsequent output primitives in a view with a HLHSR mode other than OFF.

If the workstation does not support the specified HLHSR identifier or the specified identifier is outside the allowable range, then the HLHSR identifier defaults to a value of 0. In a view with HLHSR mode set to OFF, this value is ignored and has no affect on the visualization of primitives.

HLHSR processing is often implemented by use of a z-buffer and a frame buffer. The following table summarizes the effect of the various HLHSR identifiers on the z- buffer and the frame buffer:

Table 3-1. HLHSR Processing: Summary of when the frame buffer and the z-buffer are updated.
  z-buffer Frame buffer
0=Visualize if not hidden Zprim >= Zbuf Zprim >= Zbuf
1=Visualize if hidden Zprim < Zbuf Never
2=Visualize always Always Always
3=Not Visualize Never Zprim >= Zbuf
4=Face-dependent Visualization    
      Front-facing Areas Zprim >= Zbuf Zprim >= Zbuf
      Back-facing Areas Zprim > Zbuf Zprim > Zbuf
5=No Update Never Never
6=Greater than Zprim > Zbuf Zprim > Zbuf
7=Equal to Zprim = Zbuf Zprim = Zbuf
8=Less than Zprim < Zbuf Zprim < Zbuf
9=Not Equal Zprim <> Zbuf Zprim <> Zbuf
10=Less than or Equal to Zprim <= Zbuf Zprim <= Zbuf

Note: The actual update of the z-buffer and/or the frame buffer may be prohibited by the use of the z-buffer protect mask and the frame buffer protect mask.

Language Bindings


pset_hlhsr_id (hlhsr_id)

Input Parameters

Pint hlhsr_id
HLHSR identifier.



Input Parameters

integer hrid
HLHSR identifier.


Function Requires State (PHOP,*,STOP,*)

Related Subroutines

  • Inquire HLHSR Identifier Facilities

  • Inquire HLHSR Mode Facilities

  • Set HLHSR Mode

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