Correct me if I am wrong, but if you call "glBufferData(...)" upon an existing buffer, it will resize the buffer to whatever data you upload.
Does that mean if I call something like
glBufferData(GL_ARRAY_BUFFER, 0, NULL, GL_DYNAMIC_DRAW);
it will keep the buffer in existence, but it will have size and no data?
In the description of glBufferData, it says it is acceptable to pass NULL as a data parameter, but it mentions nothing of the size parameter.
I have only seen this done with buffer orphaning. The idea is to manually map your buffer for use, this way as a user you know which portions of your buffer have been written and commit to the OpenGL driver. Once you run out of memory on your buffer you call glBufferData with a NULL parameter.
This tells OpenGL to find a new contiguous memory chunk to use. You need to pass in your desired size of this new buffer, so your example with zero is (I think) not what you want.
The reason to do this is to allow for asynchronous writing. With this method you can just send data to the GPU over and over without caring about if the previously mapped buffer sections are still locked or not (still being read by the driver).
