kripken/emscripten — pull request #2051 by inolen (2014-01-24 02:02:33+00:00)
Title: use correct bufferData method when passing a NULL pointer

It's not uncommon to pass a NULL pointer to glBufferData to invalidate the current buffer before updating parts of it with glBufferSubData:

http://www.opengl.org/wiki/Buffer_Object#Invalidation

In this case, we shouldn't upload a new buffer. This made a _huge_ difference for me in my build of ioquake3.