Ian's buffer swap extensions

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+Name
+
+    MESA_swap_control
+
+Name Strings
+
+    GLX_MESA_swap_control
+
+Contact
+
+    Ian Romanick, IBM  (idr 'at' us.ibm.com)
+
+Status
+
+    Deployed in DRI drivers post-XFree86 4.3.
+
+Version
+
+    Date: 3/17/2003   Revision: 1.0
+
+Number
+
+    ???
+
+Dependencies
+
+    None
+
+    Based on GLX_SGI_swap_control version 1.9 and WGL_EXT_swap_control
+    version 1.5.
+
+Overview
+
+    This extension allows an application to specify a minimum periodicity
+    of color buffer swaps, measured in video frame periods.
+
+New Procedures and Functions
+
+    int glXSwapIntervalMESA(int interval)
+    int glXGetSwapIntervalMESA(void)
+
+New Tokens
+
+    None
+
+Additions to Chapter 2 of the 1.4 GL Specification (OpenGL Operation)
+
+    None
+
+Additions to Chapter 3 of the 1.4 GL Specification (Rasterization)
+
+    None
+
+Additions to Chapter 4 of the 1.4 GL Specification (Per-Fragment Operations
+and the Framebuffer)
+
+    None
+
+Additions to Chapter 5 of the 1.4 GL Specification (Special Functions)
+
+    None
+
+Additions to Chapter 6 of the 1.4 GL Specification (State and State Requests)
+
+    None
+
+Additions to the GLX 1.3 Specification
+
+    [Add the following to Section 3.3.10 of the GLX Specification (Double
+     Buffering)]
+
+    glXSwapIntervalMESA specifies the minimum number of video frame periods
+    per buffer swap.  (e.g. a value of two means that the color buffers
+    will be swapped at most every other video frame.)  A return value
+    of zero indicates success; otherwise an error occurred.  The interval
+    takes effect when glXSwapBuffers is first called subsequent to the
+    glXSwapIntervalMESA call.
+
+    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.
+
+    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
+    stored.
+
+    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
+    glXGetSwapIntervalMESA.  The default swap interval is 1.
+
+    On XFree86, setting the environment variable LIBGL_NO_VSYNC sets the
+    swap interval to 0.
+
+Errors
+
+    glXSwapIntervalMESA returns GLX_BAD_VALUE if parameter <interval> is
+    less than zero.
+
+    glXSwapIntervalMESA returns GLX_BAD_CONTEXT if there is no current
+    GLXContext.
+
+GLX Protocol
+
+    None.  This extension only extends to direct rendering contexts.
+
+New State
+
+    Get Value		Get Command	Type	    Initial Value
+    ---------		-----------	----	    -------------
+    [swap interval]	GetSwapInterval	Z+	    1
+
+New Implementation Dependent State
+
+    None