lRGBrange Subroutine

GL3.2 for AIX: Graphics Library (GL) Technical Reference

lRGBrange Subroutine

Purpose

Sets the range of colors used for depth-cueing.

Libraries

Graphics Library

C (libgl.a)

FORTRAN (libfgl.a)

C Syntax

void lRGBrange
(Int16 rmin, Int16 gmin, 
Int16 bmin, Int16 rmax, 
Int16 gmax, Int16 bmax, 
Int32 znear, Int32 zfar)

FORTRAN Syntax

SUBROUTINE LRGBRA(rmin, gmin, bmin,
          rmax, gmax, bmax, znear, zfar)

INTEGER*4 rmin, gmin, bmin, rmax,
         gmax, bmax, znear, zfar

Note: For FORTRAN users, this subroutine accepts long integer parameters (INTEGER*4) when invoked from a FORTRAN program, although it accepts short integers when invoked from a C program. The C and FORTRAN syntax shown here reflect this difference.

Description

The lRGBrange subroutine sets the range of colors used in depth-cueing in RGB mode. The range is mapped linearly into the RGB color range. Any z values less than the value of the znear parameter are mapped to rmax, gmax, and bmax parameters. Any z values greater than the value of the zfar parameter are mapped to rmin, gmin, and bmin parameters.

The valid range of values for the znear and zfar parameters can be found by using the getgdesc subroutine to query GD_ZMIN and GD_ZMAX attributes. (See the getgdesc subroutine and "Tokens for the getgdesc Subroutine" .)

Note: The value for the znear parameter must be less than the value for the zfar parameter.

Parameters

rmin	Specifies the minimum value to be stored in the red bitplanes.
gmin	Specifies the minimum value to be stored in the green bitplanes.
bmin	Specifies the minimum value to be stored in the blue bitplanes.
rmax	Specifies the maximum value to be stored in the red bitplanes.
gmax	Specifies the maximum value to be stored in the green bitplanes.
bmax	Specifies the maximum value to be stored in the blue bitplanes.
znear	Specifies the minimum z value to be used as the criterion for linear mapping.
zfar	Specifies the maximum z value to be used as the criterion for linear mapping.

Implementation Specifics

This subroutine is part of GL in the AIXwindows Environment/6000 Version 1, Release 2 with AIXwindows/3D Feature.

Files

/usr/include/gl/gl.h	Contains C language constant and variable type definitions for GL.
/usr/include/gl/fgl.h	Contains FORTRAN constant and variable type definitions for GL.

Related Information

Turning depth-cueing on and off with the depthcue subroutine.

Getting information about the currently installed graphics hardware with the getgdesc subroutine.

Setting the viewport depth range with the lsetdepth subroutine.

Setting the range of color indexes used for depth-cueing with the lshaderange subroutine.

AIX Graphics Library Overview, Performing Depth-Cueing, and Working in Color Map and RGB Modes.