1GLREADBUFFER(3G)                                              GLREADBUFFER(3G)
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NAME

6       glReadBuffer - select a color buffer source for pixels
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C SPECIFICATION

10       void glReadBuffer( GLenum mode )
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PARAMETERS

14       mode  Specifies  a  color  buffer.   Accepted values are GL_FRONT_LEFT,
15             GL_FRONT_RIGHT, GL_BACK_LEFT, GL_BACK_RIGHT,  GL_FRONT,  GL_BACK,
16             GL_LEFT,  GL_RIGHT,  and  GL_AUXi,  where  i  is  between  0  and
17             GL_AUX_BUFFERS -1.
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DESCRIPTION

20       glReadBuffer specifies a color buffer  as  the  source  for  subsequent
21       glReadPixels,  glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage1D,
22       glCopyTexSubImage2D, glCopyTexSubImage3D,  and  glCopyPixels  commands.
23       mode accepts one of twelve or more predefined values.  (GL_AUX0 through
24       GL_AUX3 are always defined.)  In a fully configured  system,  GL_FRONT,
25       GL_LEFT,   and   GL_FRONT_LEFT   all   name   the  front  left  buffer,
26       GL_FRONT_RIGHT  and  GL_RIGHT  name  the  front   right   buffer,   and
27       GL_BACK_LEFT and GL_BACK name the back left buffer.
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29       Nonstereo  double-buffered  configurations have only a front left and a
30       back left buffer.  Single-buffered configurations have a front left and
31       a  front  right  buffer if stereo, and only a front left buffer if non‐
32       stereo.   It  is  an  error  to  specify  a   nonexistent   buffer   to
33       glReadBuffer.
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35       mode  is  initially  GL_FRONT  in  single-buffered  configurations, and
36       GL_BACK in double-buffered configurations.
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ERRORS

39       GL_INVALID_ENUM is generated if mode is not one of the twelve (or more)
40       accepted values.
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42       GL_INVALID_OPERATION  is generated if mode specifies a buffer that does
43       not exist.
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45       GL_INVALID_OPERATION is generated if glReadBuffer is  executed  between
46       the execution of glBegin and the corresponding execution of glEnd.
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ASSOCIATED GETS

49       glGet with argument GL_READ_BUFFER
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SEE ALSO

52       glCopyPixels(3G),      glCopyTexImage1D(3G),      glCopyTexImage2D(3G),
53       glCopyTexSubImage1D(3G),                       glCopyTexSubImage2D(3G),
54       glCopyTexSubImage3D(3G), glDrawBuffer(3G), glReadPixels(3G)
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58                                                              GLREADBUFFER(3G)