GLAPI/glReadBuffer: Difference between revisions
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== Copyright == | == Copyright == | ||
Copyright © 1991-2006 Silicon Graphics, Inc. Copyright © 2011 Khronos Group. This document is licensed under the SGI Free Software B License. For details, see [ | Copyright © 1991-2006 Silicon Graphics, Inc. Copyright © 2011 Khronos Group. This document is licensed under the SGI Free Software B License. For details, see [https://khronos.org/registry/OpenGL-Refpages/LICENSES/LicenseRef-FreeB.txt LicenseRef-FreeB]. | ||
[[Category:Core API Ref Framebuffer Objects|ReadBuffer]] | [[Category:Core API Ref Framebuffer Objects|ReadBuffer]] | ||
[[Category:Core API Reference|ReadBuffer]] | [[Category:Core API Reference|ReadBuffer]] | ||
[[Category:Framebuffer Object API State Functions|ReadBuffer]] | [[Category:Framebuffer Object API State Functions|ReadBuffer]] |
Latest revision as of 21:55, 5 February 2021
Core in version | 4.6 | |
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Core since version | 1.0 |
glReadBuffer: select a color buffer source for pixel read operations from the current read framebuffer.
Function Definition
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, GL_RIGHT, and the constants GL_COLOR_ATTACHMENTi.
Description
glReadBuffer specifies which color buffer within the current bound GL_READ_FRAMEBUFFER will be used as the source for pixel reading commands. These commands include: glBlitFramebuffer, glReadPixels, glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage1D, glCopyTexSubImage2D, and glCopyTexSubImage3D.
mode accepts one of twelve or more predefined values. If the Default Framebuffer (the zero Framebuffer Object)is bound to GL_READ_FRAMEBUFFER, then the following enumerators can be used: 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.
If a non-zero framebuffer object is bound, then 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.
It is an error to specify a nonexistent buffer to glReadBuffer.
For the default framebuffer, mode is initially GL_FRONT in single-buffered configurations and GL_BACK in double-buffered configurations. For framebuffer objects, the default read buffer is GL_COLOR_ATTACHMENT0.
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.
Associated Gets
glGet with argument GL_READ_BUFFER
See Also
glBindFramebuffer, glDrawBuffer, glDrawBuffers, glReadPixels
Copyright
Copyright © 1991-2006 Silicon Graphics, Inc. Copyright © 2011 Khronos Group. This document is licensed under the SGI Free Software B License. For details, see LicenseRef-FreeB.