bbp_get_topic_author_display_name( int $topic_id )

	function bbp_get_topic_author_display_name( $topic_id = 0 ) {
		$topic_id = bbp_get_topic_id( $topic_id );

		// Check for anonymous user
		if ( !bbp_is_topic_anonymous( $topic_id ) ) {

			// Get the author ID
			$author_id = bbp_get_topic_author_id( $topic_id );

			// Try to get a display name
			$author_name = get_the_author_meta( 'display_name', $author_id );

			// Fall back to user login
			if ( empty( $author_name ) ) {
				$author_name = get_the_author_meta( 'user_login', $author_id );
			}

		// User does not have an account
		} else {
			$author_name = get_post_meta( $topic_id, '_bbp_anonymous_name', true );
		}

		// If nothing could be found anywhere, use Anonymous
		if ( empty( $author_name ) )
			$author_name = __( 'Anonymous', 'buddyboss' );

		// Encode possible UTF8 display names
		if ( seems_utf8( $author_name ) === false )
			$author_name = utf8_encode( $author_name );

		return apply_filters( 'bbp_get_topic_author_display_name', $author_name, $topic_id );
	}