glReadBuffer, glNamedFramebufferReadBuffer — select a color buffer source for pixels
void glReadBuffer(
|
GLenum mode); |
void glNamedFramebufferReadBuffer(
|
GLuint framebuffer, |
GLenum mode); |
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.
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.
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.
glGet
with argument GL_READ_BUFFER
| 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
|
✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ |
glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage1D, glCopyTexSubImage2D, glCopyTexSubImage3D, glDrawBuffer, glReadPixels
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/.