decal glow fixes


git-svn-id: svn://svn.tuxfamily.org/svnroot/tesseract/main@1779 b412e182-2ed4-4078-95c4-27dc59f57fa9
decal glow shader cleanup


git-svn-id: svn://svn.tuxfamily.org/svnroot/tesseract/main@1780 b412e182-2ed4-4078-95c4-27dc59f57fa9
more decal glow shader cleanups


git-svn-id: svn://svn.tuxfamily.org/svnroot/tesseract/main@1781 b412e182-2ed4-4078-95c4-27dc59f57fa9
decal glow shader typo fix


git-svn-id: svn://svn.tuxfamily.org/svnroot/tesseract/main@1782 b412e182-2ed4-4078-95c4-27dc59f57fa9