Function SetViewportCatchmentWaypoint

src/viewport.cpp:3759–3774

* Select or deselect waypoint for coverage area highlight. * Selecting a waypoint will deselect a town. * @param *wp Waypoint in question * @param sel Select or deselect given waypoint */

 * @param sel Select or deselect given waypoint
 */
void SetViewportCatchmentWaypoint(const Waypoint *wp, bool sel)
{
	SetWindowDirtyForViewportCatchment();
	/* Mark tiles dirty for redrawing and update selected waypoint if a different waypoint is already highlighted. */
	if (sel && _viewport_highlight_waypoint != wp) {
		ClearViewportCatchment();
		_viewport_highlight_waypoint = wp;
		MarkCatchmentTilesDirty();
	/* Mark tiles dirty for redrawing and clear waypoint selection if deselecting highlight. */
	} else if (!sel && _viewport_highlight_waypoint == wp) {
		MarkCatchmentTilesDirty();
		_viewport_highlight_waypoint = nullptr;
	}
	/* Redraw the currently selected waypoint window */
	if (_viewport_highlight_waypoint != nullptr) SetWindowDirty(WC_WAYPOINT_VIEW, _viewport_highlight_waypoint->index);
}

/**
 * Select or deselect waypoint for rectangle area highlight.