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

RGBmode Subroutine

Purpose

Sets a display mode that bypasses the color map.

Libraries

Graphics Library

C (libgl.a)

FORTRAN (libfgl.a)

C Syntax

void RGBmode( )

FORTRAN Syntax

SUBROUTINE RGBMOD

Description

The RGBmode subroutine makes the system interpret the contents of the main frame buffer as RGB values. All drawing subroutines write values of red, green, and blue directly into the bitplanes; the contents of the frame buffer, in turn, directly control the intensity of the color displayed on the monitor.

When the frame buffer is 24 bits deep, 8 bits each of red, green, and blue are stored. When the frame buffer is 12 bits deep, the 4 most significant bits of each of the red, green, and blue are stored. When the frame buffer is 8 bits deep, the 3 most significant bits of each of the red and green, and the 2 most significant bits of blue are stored. To improve the visual quality of the displayed image, dithering is automatically turned on whenever the frame buffer is 8 bits deep.

The depth of the frame buffer depends on the installed adapter, and on how it has been configured. In particular, the doublebuffer and singlebuffer subroutines affect the configuration of the main frame buffer.

The system will not enter into RGB mode until the gconfig subroutine is called.

Note: This subroutine cannot be used to add to a display list.

Implementation Specifics

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

The RGBmode subroutine is useful for monitors with 12 or more bitplanes.

The POWERgraphics GXT1000 will ignore the RGBmode subroutine when applied to windows created with the winX subroutine. The RGBmode subroutine can be used with windows created with the winopen subroutine.

Example

The example C language program localatten.c puts the system in RGB mode with the RGBmode subroutine to perform lighting calculations. This lets the system calculate the correct colors for realistic shading.

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

Setting color map mode as the current mode with the cmode subroutine.

Reconfiguring the system with the gconfig subroutine.

Returning the current display mode with the getdisplaymode subroutine.

Working in Color Map and RGB Modes.


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