The graPHIGS Programming Interface : Subroutine Reference

Summary of Amendments

The IBM GDDM/graPHIGS API Programming Interface 2.2.5 and IBM AIXwindows Environment/6000 (1.2.5) 3D Feature (April 1994) offer several new functions which are described in the following locations.

The summary below represents new and enhanced changes for the entire graPHIGS library.

Documented Function Additions/Enhancements include:

Modeling Clipping

Modeling Clipping provides a way to clip geometric entities in World Coordinates (WC) just after the modeling transformation and before any other rendering pipeline operations. Interfaces supporting Modeling Clip are:

Set Modeling Clipping Indicator (GPMCI)
Set Modeling Clipping Volume 2 (GPMCV2)
Set Modeling Clipping Volume 3 (GPMCV3)
Inquire Workstation Description (GPQWDT)
Restore Modeling Clipping Volume (GPRMCV)

Texture Mapping

Texture mapping is a method of filling the interior of area primitives from a collection of colors. The colors are written to the frame buffer as the primitive is rendered, and become the interior of the primitive. Interfaces that support texture mapping are:

Set Data Filtering Method (GPDFM)
Set Back Data Filtering Method (GPBDFM)
Set Data Mapping Index (GPDMI)
Set Back Data Mapping Index (GPBDMI)
Set Data Mapping Representation (GPDMR)
Inquire Data Mapping Representation (GPQDMR)
Set Data Matrix 2 (GPDM2)
Set Back Data Matrix 2 (GPBDM2)

Transparency

Additions to existing transparency functions include enhanced transparency support for blending, including alpha blending using alpha planes, and multiple levels of screendoor transparency. Interfaces that support transparency are:

Set Transparency Coefficient (GPTCO)
Set Back Transparency Coefficient (GPBTCO)
Set Blending Function (GPBLF)
Set Back Blending Function (GPBBLF)

Also affected by transparency support are:

Set Surface Properties (GPSPR)
Set Back Surface Properties (GPBSPR)
Inquire Current View Representation (GPQCVR)
Inquire Requested View Representation (GPQRVR)
Set Extended View Representation (GPXVR)

PHIGS PLUS (Lighting and Shading)

PHIGS PLUS defines several new functions to support lighting and shading. The following calls allow additional application control of processing:

Set Reflectance Model (GPRMO)
Set Back Reflectance Model (GPBRMO)
Set Interior Shading Method (GPISM)
Set Back Interior Shading Method (GPBISM)

Morphing

Morphing is a method of changing the rendering of a primitive without editing the element. It gives you the ability to change the displayed value of primitive coordinates or data mapping values using morphing factors. New interfaces include:

Set Data Morphing Factors (GPDMF)
Set Back Data Morphing Factors (GPBDMF)
Set Vertex Morphing Factors (GPVMF)

Line-on-Line Highlighting

LOL highlighting is a frame-buffer comparison operation which highlights the intersection of geometry on the screen by drawing the intersection in a highlight color. New/changed interfaces include:

Set Line-on-Line Color Direct (GPLLCD)
Set Line-on-Line Color Index (GPLLCI)
Set Frame Buffer Comparison (GPFBC)

Procopts

You can use procopts to change the way in which the API treats specific devices or to specify workstation-specific default values. New processing options for this release include:

DCMETERS - Device Coordinate Meters
DCUNITS - Device Coordinate Address Units
IMAGEFMT - Image Output Format
PNTHLHSR - Annotation Text and Marker Hidden Line Hidden Surface Removal

Additional miscellaneous enhancements include:

Changes to the Vertex3 and Vertex2 formats to allow specification of values for alpha blending, texture mapping, and vertex and data morphing at the vertex of primitives
Support of the new Inquire Workstation Description (GPQWDT) function
Allow specification of boundary flags per vertex for Triangle Strip 3
Additional supported graphic adapters and workstations include the POWER GXT 1000, XSOFT, and IMAGE.