GLREADBUFFER(3G) GLREADBUFFER(3G)

glReadBuffer - select a color buffer source for pixels

void glReadBuffer( GLenum 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.










glReadBuffer specifies a color buffer as the source for
    subsequent glReadPixels, glCopyTexImage1D,
    glCopyTexImage2D, glCopyTexSubImage1D,
    glCopyTexSubImage2D, glCopyTexSubImage3D, and
    glCopyPixels 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 glReadBuffer.


mode is initially GL_FRONT in single-buffered
    configurations, and GL_BACK in double-buffered configurations.








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 glReadBuffer is
    executed between the execution of glBegin and the corresponding
    execution of glEnd.








glGet with argument GL_READ_BUFFER








glCopyPixels, glCopyTexImage1D,
    glCopyTexImage2D, glCopyTexSubImage1D,
    glCopyTexSubImage2D, glCopyTexSubImage3D, glDrawBuffer,
    glReadPixels