msaa sample checking fixes


git-svn-id: svn://svn.tuxfamily.org/svnroot/tesseract/main@1614 b412e182-2ed4-4078-95c4-27dc59f57fa9
create msaa textures with the number of determined samples


git-svn-id: svn://svn.tuxfamily.org/svnroot/tesseract/main@1615 b412e182-2ed4-4078-95c4-27dc59f57fa9
fix msaa sample position checking


git-svn-id: svn://svn.tuxfamily.org/svnroot/tesseract/main@1616 b412e182-2ed4-4078-95c4-27dc59f57fa9
always use fixed sample locations to simplify multisample g-buffer creation


git-svn-id: svn://svn.tuxfamily.org/svnroot/tesseract/main@1617 b412e182-2ed4-4078-95c4-27dc59f57fa9