Simplified GTexturePaintW

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@24049 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
New attempt for defensive texture setting (r24043 didn't work)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@24050 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e