win32: Convert the API to being based on function pointers, like Linux.

For performance, I want to be able to make single-context (well,
single-pixel-format-and-device) apps be able to directly call GL
functions through function pointers.  Bake that into the ABI now so I
can get a release out the door and fix this up later.

This also fixes the lack of __stdcall annotation on the
PFNWHATEVERPROC typedefs.

1 files changed, 10 insertions, 0 deletions

diff --git a/README.md b/README.md
index b52faed..a0fab31 100644
--- a/README.md
+++ b/README.md
@@ -119,3 +119,13 @@ pixel format.  If ```wglMakeCurrent()``` is called from outside of
 epoxy (in a way that might change the device or pixel format), then
 epoxy needs to be notified of the change using
 ```epoxy_handle_external_wglMakeCurrent()```.
+
+The win32 dispatch layer is currently slower than it should be in the
+single-context (or multi-context, but same device and pixel format)
+case.  We need to switch to using the linux-like function pointer
+stubs, and detect when transitioning to multi-device/format and hook
+in the per-thread dispatch table at that point.
+
+The win32 wglMakeCurrent () variants are slower than they should be,
+because they should be caching the resolved dispatch tables instead of
+resetting an entire thread-local dispatch table every time.