Documented framebuffer attribute retrieval.

Related to #476.
This commit is contained in:
Camilla Berglund 2015-03-29 14:18:49 +02:00
parent f3270d4ce8
commit 427c79b24b

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@ -762,6 +762,37 @@ This is `GLFW_LOSE_CONTEXT_ON_RESET` or `GLFW_NO_RESET_NOTIFICATION` if the
window's context supports robustness, or `GLFW_NO_ROBUSTNESS` otherwise.
@subsubsection window_attribs_fb Framebuffer related attributes
The attributes of the default framebuffer (i.e. the framebuffer attached to the
window) are not provided by this function but can be queried with both OpenGL
and OpenGL ES.
If you are using version 3.0 or later of OpenGL or OpenGL ES, the
`glGetFramebufferAttachmentParameteriv` function can be used to retrieve the
number of bits for the red, green, blue, alpha, depth and stencil buffer
channels. Otherwise, the `glGetIntegerv` function can be used.
The number of MSAA samples are always retrieved with `glGetIntegerv`. For
contexts supporting framebuffer objects, the number of samples of the currently
bound framebuffer is returned.
Attribute | glGetIntegerv | glGetFramebufferAttachmentParameteriv
------------ | ----------------- | -------------------------------------
Red bits | `GL_RED_BITS` | `GL_FRAMEBUFFER_ATTACHMENT_RED_SIZE`
Green bits | `GL_GREEN_BITS` | `GL_FRAMEBUFFER_ATTACHMENT_GREEN_SIZE`
Blue bits | `GL_BLUE_BITS` | `GL_FRAMEBUFFER_ATTACHMENT_BLUE_SIZE`
Alpha bits | `GL_ALPHA_BITS` | `GL_FRAMEBUFFER_ATTACHMENT_ALPHA_SIZE`
Depth bits | `GL_DEPTH_BITS` | `GL_FRAMEBUFFER_ATTACHMENT_DEPTH_SIZE`
Stencil bits | `GL_STENCIL_BITS` | `GL_FRAMEBUFFER_ATTACHMENT_STENCIL_SIZE`
MSAA samples | `GL_SAMPLES` | _Not provided by this function_
When calling `glGetFramebufferAttachmentParameteriv`, the red, green, blue and
alpha sizes can be queried from the `GL_BACK_LEFT`, while the depth and stencil
sizes can be queried from the `GL_DEPTH` and `GL_STENCIL` attachments,
respectively.
@section buffer_swap Buffer swapping
GLFW windows are by default double buffered. That means that you have two