Function DrawRailCatenaryOnBridge

src/elrail.cpp:490–543

* Draws wires on a tunnel tile * * DrawTile_TunnelBridge() calls this function to draw the wires on the bridge. * * @param ti The Tileinfo to draw the tile for */

 * @param ti The Tileinfo to draw the tile for
 */
void DrawRailCatenaryOnBridge(const TileInfo *ti)
{
	TileIndex end = GetSouthernBridgeEnd(ti->tile);
	TileIndex start = GetOtherBridgeEnd(end);

	uint length = GetTunnelBridgeLength(start, end);
	uint num = GetTunnelBridgeLength(ti->tile, start) + 1;

	Axis axis = GetBridgeAxis(ti->tile);
	TileLocationGroup tlg = GetTileLocationGroup(ti->tile);

	RailCatenarySprite offset = (RailCatenarySprite)(axis == AXIS_X ? 0 : WIRE_Y_FLAT_BOTH - WIRE_X_FLAT_BOTH);

	const SortableSpriteStruct *sss;
	if ((length % 2) && num == length) {
		/* Draw the "short" wire on the southern end of the bridge
		 * only needed if the length of the bridge is odd */
		sss = &_rail_catenary_sprite_data[WIRE_X_FLAT_BOTH + offset];
	} else {
		/* Draw "long" wires on all other tiles of the bridge (one pylon every two tiles) */
		sss = &_rail_catenary_sprite_data[WIRE_X_FLAT_SW + (num % 2) + offset];
	}

	uint height = GetBridgePixelHeight(end);

	SpriteID wire_base = GetWireBase(end, TCX_ON_BRIDGE);

	AddSortableSpriteToDraw(wire_base + sss->image_offset, PAL_NONE, ti->x, ti->y, height, *sss, IsTransparencySet(TO_CATENARY));

	SpriteID pylon_base = GetPylonBase(end, TCX_ON_BRIDGE);

	static constexpr SpriteBounds pylon_bounds{{-1, -1, 0}, {1, 1, BB_HEIGHT_UNDER_BRIDGE}, {1, 1, 0}};

	/* Finished with wires, draw pylons
	 * every other tile needs a pylon on the northern end */
	if (num % 2) {
		DiagDirection pcp_pos = (axis == AXIS_X ? DIAGDIR_NE : DIAGDIR_NW);
		Direction ppp_pos = (axis == AXIS_X ? DIR_NW : DIR_NE);
		if (HasBit(tlg, (axis == AXIS_X ? 0 : 1))) ppp_pos = ReverseDir(ppp_pos);
		uint x = ti->x + _x_pcp_offsets[pcp_pos] + _x_ppp_offsets[ppp_pos];
		uint y = ti->y + _y_pcp_offsets[pcp_pos] + _y_ppp_offsets[ppp_pos];
		AddSortableSpriteToDraw(pylon_base + _pylon_sprites[ppp_pos], PAL_NONE, x, y, height, pylon_bounds, IsTransparencySet(TO_CATENARY));
	}

	/* need a pylon on the southern end of the bridge */
	if (GetTunnelBridgeLength(ti->tile, start) + 1 == length) {
		DiagDirection pcp_pos = (axis == AXIS_X ? DIAGDIR_SW : DIAGDIR_SE);
		Direction ppp_pos = (axis == AXIS_X ? DIR_NW : DIR_NE);
		if (HasBit(tlg, (axis == AXIS_X ? 0 : 1))) ppp_pos = ReverseDir(ppp_pos);
		uint x = ti->x + _x_pcp_offsets[pcp_pos] + _x_ppp_offsets[ppp_pos];
		uint y = ti->y + _y_pcp_offsets[pcp_pos] + _y_ppp_offsets[ppp_pos];
		AddSortableSpriteToDraw(pylon_base + _pylon_sprites[ppp_pos], PAL_NONE, x, y, height, pylon_bounds, IsTransparencySet(TO_CATENARY));
	}
}

/**
 * Draws overhead wires and pylons for electric railways.