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OpenGL 1.1 for AIX: Reference Manual

glReadBuffer Subroutine


Selects a color buffer source for pixels.


OpenGL C bindings library: libGL.a

C Syntax

void glReadBuffer(GLenum Mode)


Mode Specifies a color buffer. Accepted values are as follows:
  • GL_AUXi, where i is between 0 (zero) and GL_AUX_BUFFERS - 1


The glReadBuffer subroutine specifies a color buffer as the source for subsequent glReadPixels and glCopyPixels subroutines. The Mode parameter 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 configurations have only a left buffer, or a front left and a back left buffer if double-buffered. Single-buffered configurations have only a front buffer, or a front left and a front right buffer if stereo. It is an error to specify a nonexistent buffer to glReadBuffer.

By default, the Mode parameter is GL_FRONT in single-buffered configurations and GL_BACK in double-buffered configurations.

Error Codes

GL_INVALID_ENUM Mode is not one of the twelve (or more) accepted values.
GL_INVALID_OPERATION Mode specifies a buffer that does not exist.
GL_INVALID_OPERATION The glReadBuffer subroutine is called between a call to glBegin and the corresponding call to glEnd.

Associated Gets

Associated gets for the glReadBuffer subroutine are as follows. (See the glGet subroutine.)

glGet with argument GL_READ_BUFFER.


/usr/include/GL/gl.h Contains C language constants, variable type definitions, and ANSI function prototypes for OpenGL.

Related Information

The glBegin or glEnd subroutine, glCopyPixels subroutine, glDrawBuffer subroutine, glReadPixels subroutine.

OpenGL Overview.

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