nl_tokens: Creates a perspective matrix .
pl_tokens: function makePersp ( hfov , aspect , znear , zfar ) { var fovy = 2 * Math . atan ( Math . tan ( hfov / 2 ) * gl . drawingBufferHeight / gl . drawingBufferWidth ) ; <mask> f = 1 / Math . tan ( fovy / 2 ) ; return [ f / aspect , 0 , 0 , 0 , 0 , f , 0 , 0 , 0 , 0 , ( zfar + znear ) / ( znear - zfar ) , ( 2 * zfar * znear ) / ( znear - zfar ) , 0 , 0 , - 1 , 0 ] ; }