glReadBuffer.3G - Man Page
select a color buffer source for pixels
C Specification
void glReadBuffer(GLenum mode);
void glNamedFramebufferReadBuffer(GLuint framebuffer, GLenum mode);
Parameters
- framebuffer
Specifies the name of the framebuffer object for glNamedFramebufferReadBuffer function.
- 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 the constants GL_COLOR_ATTACHMENTi.
Description
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. Further more, 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.
For glReadBuffer, the target framebuffer object is that bound to GL_READ_FRAMEBUFFER. For glNamedFramebufferReadBuffer, framebuffer must either be zero or the name of the target framebuffer object. If framebuffer is zero, then the default read framebuffer is affected.
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 by glNamedFramebufferReadBuffer if framebuffer is not zero or the name of an existing framebuffer object.
Associated Gets
glGet() with argument GL_READ_BUFFER
Version Support
| OpenGL Version | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Function / Feature Name | 2.0 | 2.1 | 3.0 | 3.1 | 3.2 | 3.3 | 4.0 | 4.1 | 4.2 | 4.3 | 4.4 | 4.5 |
| glNamedFramebufferReadBuffer | - | - | - | - | - | - | - | - | - | - | - | ✔ |
| glReadBuffer | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ |
See Also
glCopyTexImage1D(), glCopyTexImage2D(), glCopyTexSubImage1D(), glCopyTexSubImage2D(), glCopyTexSubImage3D(), glDrawBuffer(), glReadPixels()
Copyright
Copyright © 1991-2006 Silicon Graphics, Inc. Copyright © 2011-2014 Khronos Group. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.
Copyright
Copyright © 1991-2006 Silicon Graphics, Inc.
Copyright © 2011-2014 Khronos Group
Referenced By
glAccum.3G(3), glCopyPixels.3G(3), glCopyTexSubImage1D.3G(3), glCopyTexSubImage2D.3G(3), glCopyTexSubImage3D.3G(3), glDrawBuffer.3G(3), glDrawBuffers.3G(3), glReadPixels.3G(3).
The man page glNamedFramebufferReadBuffer.3G(3) is an alias of glReadBuffer.3G(3).