blob: 33071a0b58c46104000f261a2d447ce764d5b368 [file] [log] [blame]
Name Strings
Date: 9/23/1999 Revision: 1.5
WGL_EXT_extensions_string is required.
This extension allows an application to specify a minimum periodicity
of color buffer swaps, measured in video frame periods.
New Procedures and Functions
BOOL wglSwapIntervalEXT(int interval)
int wglGetSwapIntervalEXT(void)
New Tokens
Additions to Chapter 2 of the 1.2 GL Specification (OpenGL Operation)
Additions to Chapter 3 of the 1.2 GL Specification (Rasterization)
Additions to Chapter 4 of the 1.2 GL Specification (Per-Fragment Operations
and the Framebuffer)
Additions to Chapter 5 of the 1.2 GL Specification (Special Functions)
Additions to Chapter 6 of the 1.2 GL Specification (State and State Requests)
Additions to the WGL Specification
wglSwapIntervalEXT specifies the minimum number of video frame periods
per buffer swap for the window associated with the current context.
The interval takes effect when SwapBuffers or wglSwapLayerBuffer
is first called subsequent to the wglSwapIntervalEXT call.
The parameter <interval> specifies the minimum number of video frames
that are displayed before a buffer swap will occur.
A video frame period is the time required by the monitor to display a
full frame of video data. In the case of an interlaced monitor,
this is typically the time required to display both the even and odd
fields of a frame of video data. An interval set to a value of 2
means that the color buffers will be swapped at most every other video
If <interval> is set to a value of 0, buffer swaps are not synchron-
ized to a video frame. The <interval> value is silently clamped to
the maximum implementation-dependent value supported before being
The swap interval is not part of the render context state. It cannot
be pushed or popped. The current swap interval for the window
associated with the current context can be obtained by calling
wglGetSwapIntervalEXT. The default swap interval is 1.
Dependencies on WGL_EXT_extensions_string
Because there is no way to extend wgl, these calls are defined in
the ICD and can be called by obtaining the address with
wglGetProcAddress. Because this extension is a WGL extension, it
is not included in the GL_EXTENSIONS string. Its existence can be
determined with the WGL_EXT_extensions_string extension.
For historical reasons, GL_EXT_SWAP_CONTROL is also included in the
GL_EXTENSIONS string as return from glGetString.
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.
ERROR_INVALID_DATA The <interval> parameter is negative.
ERROR_DC_NOT_FOUND An RC was not current to the calling
thread; therefore, no DC could be
New State
New Implementation Dependent State