glReadBuffer — select a color buffer source for pixels
void glReadBuffer(
GLenum mode)
;
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
, and the constants GL_COLOR_ATTACHMENTi
.
glReadBuffer
specifies a color buffer as the source for subsequent glReadPixels, glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage1D, glCopyTexSubImage2D, and glCopyTexSubImage3D commands. mode
accepts one of twelve or more predefined values. 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. Furthermore, the constants GL_COLOR_ATTACHMENTi
may be used to indicate the ith color attachment where i ranges from zero to the value of GL_MAX_COLOR_ATTACHMENTS
minus one.
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.
glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage1D, glCopyTexSubImage2D, glCopyTexSubImage3D, glDrawBuffer, glReadPixels
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