readsource Subroutine

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

Specifies the source for pixels to be read by various subroutines.

Graphics Library

C (libgl.a)

FORTRAN (libfgl.a)

void readsource(Int32 source)

SUBROUTINE READSO(source)
INTEGER*4 source

The readsource subroutine specifies the exact pixel source (front buffer, back buffer, or z-buffer) that the rectcopy, readpixels, readRGB, and rectread subroutines use.

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

source

The defined values for this parameter are listed in the following table:

Values for the source Parameter
C	FORTRAN	Function
SRC_AUTO	SRCAUT	Selects the front buffer in single buffer mode and the back buffer in double buffer mode.
SRC_FRONT	SRCFRO	Front color buffer. Valid for both single and double buffer operation.
SRC_BACK	SRCBAC	Back color buffer. Valid during double buffer operation only.
SRC_ZBUFFER	SRCZBU	Z-buffer. Valid during both single and double buffer operation.
SRC_OVER	SRCOVE	Overlay planes.

Note: The 3-D Color Graphics Processor does not support SRC_OVER.

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

BLITs to and from the z-buffer are currently inoperational on the POWER GXT1000 adapter.

When performing BLITs to and from the overlay planes on the GXT1000, the transparent pixel value on the GXT1000 is 255, not 0.

/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.

Copying a rectangle of pixels with an optional zoom with the rectcopy subroutine.

Reading a rectangular array of pixels into host memory with the rectread subroutine.