lshaderange Subroutine

Purpose

Sets the range of color indexes used in depth-cueing.

Libraries

Graphics Library

C (libgl.a)

FORTRAN (libfgl.a)

C Syntax

void lshaderange
(Colorindex lowindex, Colorindex highindex, 
Int32 znear, Int32 zfar)

FORTRAN Syntax

SUBROUTINE LSHADE(lowindex, highindex, znear, zfar)
INTEGER*4 lowindex, highindex, 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 lshaderange subroutine sets the range of color indexes used for depth-cueing. The range is mapped linearly into the color index range. Any z values less than the value of the znear parameter map to the highindex parameter; z values greater than the zfar parameter map to the lowindex parameter.

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. The default is lshaderange(0, 7, zmin, zmax). (See also "Tokens for the getgdesc Subroutine" .)

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

Parameters

Example

The example C language program depthcue.c uses the lshaderange subroutine to map the z-axis values to a spread of colors in the color map.

Implementation Specifics

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

Files

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 range of RGB colors used for depth-cueing with the lRGBrange subroutine.

Setting the viewport depth range with the lsetdepth subroutine.

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