Until recently (or maybe not too recently) ES3 extension header was
"currently empty", now the extension header is shared with ES2. It's
nice to finally get rid of all the weird ifndefs.
Buffer usage is used as parameter in many functions, e.g. in
*Framebuffer::read() and *Texture::image(), but they are rather seldom
used and including whole Buffer.h file just for one enum is just
overkill. The old Buffer::Usage is now alias to BufferUsage, it is
marked as deprecated and will be removed in future release.
Makes the lines shorter, the conversions are mainly from strongly-typed
enums to underlying type, so nothing potentially harmful which should be
marked with static_cast.
Passing pointer as function parameter will now mean that it is possible
to pass `nullptr`. Some code examples now look like the parameter is
copied instead of referenced, which is misleading. Updated the
documentation to reflect that more clearly.
If ARB_invalidate_subdata is not available, these functions do nothing,
instead of crashing on null pointer dereference. It results in more
convenient usage, enabling users to call them whenever they want,
improving performance on implementations which supports that.
SizeTraits class provides suitable types for given data size at compile
time, SizeBasedCall can call suitable templated overload based on given
data size at runtime.
Also added meta classes Pow and Log for computing powers and logarithms
at compile time, usable mainly in conjunction with SizeTraits. Their
implementation is checked at compile-time using static_cast().