wglSwapLayerBuffers
[New
- Windows 95, OEM Service Release 2]
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.
BOOL wglSwapLayerBuffers(
|
HDC hdc, |
// device
context whose layer plane buffers are to be swapped |
|
UINT fuPlanes |
//
specifies the overlay, underlay and main planes to be swapped |
|
); |
|
Parameters
hdc
Specifies the
device context of a window whose layer plane palette is to be realized into the
physical palette.
fuPlanes
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 Values
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.
See Also