wglSwapLayerBuffers function (wingdi.h)

Article
01/20/2022

The wglSwapLayerBuffers function swaps the front and back buffers in the overlay, underlay, and main planes of the window referenced by a specified device context.

Syntax

BOOL wglSwapLayerBuffers(
  HDC  unnamedParam1,
  UINT unnamedParam2
);

Parameters

unnamedParam1

Specifies the device context of a window whose layer plane palette is to be realized into the physical palette.

unnamedParam2

Specifies the overlay, underlay, and main planes whose front and back buffers are to be swapped. The bReserved member of the PIXELFORMATDESCRIPTOR structure specifies the number of overlay and underlay planes. The fuPlanes parameter is a bitwise combination of the following values.

Value	Meaning
WGL_SWAP_MAIN_PLANE	Swaps the front and back buffers of the main plane.
WGL_SWAP_OVERLAYi	Swaps the front and back buffers of the overlay plane i, where i is an integer between 1 and 15. WGL_SWAP_OVERLAY1 identifies the first overlay plane over the main plane, WGL_SWAP_OVERLAY2 identifies the second overlay plane over the first overlay plane, and so on.
WGL_SWAP_UNDERLAYi	Swaps the front and back buffers of the underlay plane i, where i is an integer between 1 and 15. WGL_SWAP_UNDERLAY1 identifies the first underlay plane under the main plane, WGL_SWAP_UNDERLAY2 identifies the second underlay plane under the first underlay plane, and so on.

Return value

If the function succeeds, the return value is TRUE. If the function fails, the return value is FALSE. To get extended error information, call GetLastError.

Remarks

When a layer plane doesn't include a back buffer, calling the wglSwapLayerBuffers function has no effect on that layer plane. After you call wglSwapLayerBuffers, the state of the back buffer content is given in the corresponding LAYERPLANEDESCRIPTOR structure of the layer plane or in the PIXELFORMATDESCRIPTOR structure of the main plane. The wglSwapLayerBuffers function swaps the front and back buffers in the specified layer planes simultaneously.

Some devices don't support swapping layer planes individually; they swap all layer planes as a group. When the PFD_SWAP_LAYER_BUFFERS flag of the PIXELFORMATDESCRIPTOR structure is set, it indicates that a device can swap individual layer planes and that you can call wglSwapLayerBuffers.

With applications that use multiple threads, before calling wglSwapLayerBuffers, clear all drawing commands in all threads drawing to the same window.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	wingdi.h
Library	Opengl32.lib
DLL	Opengl32.dll