Aggressively unbind GL_PIXEL_UNPACK_BUFFER

Bug: 27186019

Theory: It appears to be possible for FontRenderer
to not unbind its PBO prior to textures being uploaded,
resulting in trying to glSubTexImage2D with a bound
GL_PIXEL_UNPACK_BUFFER. In that scenario the void* is
the offset into the PBO which given a non-null data
will almost certainly overrun the end of the buffer. This
in turn produces a GL_INVALID_OPERATION error.

Change PixelBuffer to avoid leaking this state for now.
This will result in more calls to glBindBuffer/glUnbindBuffer
in the worst case, but the worst case is already bad so this
shouldn't be a problem. In the normal case we avoid binding
the PBO at all ever, so this doesn't impact that.

Change-Id: I05473f0d2f9a3a5da0e33d8f9ddea4731ce970e3

0 files changed, 0 insertions, 0 deletions