fglReadBuffer(3G) OpenGL Reference fglReadBuffer(3G)NAME
fglReadBuffer - select a color buffer source for pixels
FORTRAN SPECIFICATION
SUBROUTINE fglReadBuffer( INTEGER*4 mode )
PARAMETERS
mode Specifies a color buffer. Accepted values are GL_FRONT_LEFT,
GL_FRONT_RIGHT, GL_BACK_LEFT, GL_BACK_RIGHT, GL_FRONT, GL_BACK,
GL_LEFT, GL_RIGHT, and GL_AUXi, where i is between 0 and
GL_AUX_BUFFERS -1.
DESCRIPTION
fglReadBuffer specifies a color buffer as the source for subsequent
fglReadPixels, fglCopyTexImage1D, fglCopyTexImage2D,
fglCopyTexSubImage1D, fglCopyTexSubImage2D, fglCopyTexSubImage3D, and
fglCopyPixels commands. mode accepts one of twelve or more predefined
values. (GL_AUX0 through GL_AUX3 are always defined.) In a fully
configured system, GL_FRONT, GL_LEFT, and GL_FRONT_LEFT all name the
front left buffer, GL_FRONT_RIGHT and GL_RIGHT name the front right
buffer, and GL_BACK_LEFT and GL_BACK name the back left buffer.
Nonstereo double-buffered configurations have only a front left and a
back left buffer. Single-buffered configurations have a front left and a
front right buffer if stereo, and only a front left buffer if nonstereo.
It is an error to specify a nonexistent buffer to fglReadBuffer.
mode is initially GL_FRONT in single-buffered configurations, and GL_BACK
in double-buffered configurations.
ERRORS
GL_INVALID_ENUM is generated if mode is not one of the twelve (or more)
accepted values.
GL_INVALID_OPERATION is generated if mode specifies a buffer that does
not exist.
GL_INVALID_OPERATION is generated if fglReadBuffer is executed between
the execution of fglBegin and the corresponding execution of fglEnd.
ASSOCIATED GETS
fglGet with argument GL_READ_BUFFER
SEE ALSO
fglCopyPixels, fglCopyTexImage1D, fglCopyTexImage2D,
fglCopyTexSubImage1D, fglCopyTexSubImage2D, fglCopyTexSubImage3D,
fglDrawBuffer, fglReadPixels
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