Name

PSHRM − Specifies the mode value to control hidden line and hidden surface removal attributes. 

Operating States: PHOP, WSOP, ∗, ∗
PHIGS standard function

Syntax

PSHRM (WKID, HRM)

Argument       Data Type      Access     Description
---------------------------------------------------------------------------
WKID           Integer        Read       Workstation identifier
HRM            Integer        Read       HLHSR mode
---------------------------------------------------------------------------

Constants

Defined Argument     Constant      Description
---------------------------------------------------------------------------
HRM                  PHRMN         Use the HLHSR identifier.  This is
                                   the default value.
                     PHRMPT        Painters sort algorithm.
                     PHRMZB        Z-buffer algorithm.
                     PHRMSC        Scan line algorithm.
                     PHRMHL        Hidden line algorithm.
---------------------------------------------------------------------------

Description

PSHRM specifies the HLHSR mode value to control hidden line and hidden surface removal attributes on the workstation specified by the workstation identifier.  This function sets the requested HLHSR mode entry in the workstation state list of the specified workstation to the specified mode value.  The effect of the specified mode value is influenced by the current settings of the dynamic modification accepted for HLHSR mode (DMA) entry in the workstation description table and the display surface empty (DSE) entry in the workstation state list. 

If the dynamic modification accepted for HLHSR mode entry in the workstation description table is set to IMM, or if the display surface empty entry in the workstation state list is EMPTY, Digital PHIGS sets the current HLHSR mode entry in the workstation state list to the value specified by the parameter, and the HLHSR update state to NOTPENDING.  Otherwise, Digital PHIGS sets the HLHSR update state entry in the workstation state list to PENDING, and the current HLHSR mode entry is not changed. 

Digital PHIGS recognizes the following HLHSR modes:

•None---Use the HLHSR identifier to determine the type of HLHSR processing.  This is the default value. 

•Painters---Digital PHIGS sorts all the primitives by their average Z value and sends them to the device in back-to-front order.  This is a fast HLHSR method, and yields reasonable results in many cases.  This method is not supported on PEX workstations. 

•Z-buffer---Digital PHIGS uses a Z-buffer algorithm.  Every pixel has a Z value associated with it.  When the hardware "lights" a pixel, it checks the Z buffer value for that pixel.  If the value is less than the value for the primitive that is being drawn, the pixel gets the new value (both color and Z buffer).  This is supported only on PEX workstations. 

•Scan line---Currently not implemented. 

•Hidden line---Currently not implemented. 

•Ignore ID---Digital PHIGS performs no HLHSR processing. 

To check which HLHSR modes are supported by your device, call the PQHRMF function. 

If Digital PHIGS is in immediate mode, it performs this function immediately, but the function does not create a structure element. 

See Also

  PQHRIF
PQHRM
PQHRMF
PSHRID