Function DrawRoadOverlays

src/road_cmd.cpp:1505–1541

* Draw road underlay and overlay sprites. * @param ti TileInfo * @param road_rti Road road type information * @param tram_rti Tram road type information * @param road_offset Road sprite offset (based on road bits) * @param tram_offset Tram sprite offset (based on road bits) * @param draw_underlay Whether to draw underlays */

 * @param draw_underlay Whether to draw underlays
 */
void DrawRoadOverlays(const TileInfo *ti, PaletteID pal, const RoadTypeInfo *road_rti, const RoadTypeInfo *tram_rti, uint road_offset, uint tram_offset, bool draw_underlay)
{
	if (draw_underlay) {
		/* Road underlay takes precedence over tram */
		if (road_rti != nullptr) {
			if (road_rti->UsesOverlay()) {
				SpriteID ground = GetCustomRoadSprite(road_rti, ti->tile, ROTSG_GROUND);
				DrawGroundSprite(ground + road_offset, pal);
			}
		} else {
			if (tram_rti->UsesOverlay()) {
				SpriteID ground = GetCustomRoadSprite(tram_rti, ti->tile, ROTSG_GROUND);
				DrawGroundSprite(ground + tram_offset, pal);
			} else {
				DrawGroundSprite(SPR_TRAMWAY_TRAM + tram_offset, pal);
			}
		}
	}

	/* Draw road overlay */
	if (road_rti != nullptr) {
		if (road_rti->UsesOverlay()) {
			SpriteID ground = GetCustomRoadSprite(road_rti, ti->tile, ROTSG_OVERLAY);
			if (ground != 0) DrawGroundSprite(ground + road_offset, pal);
		}
	}

	/* Draw tram overlay */
	if (tram_rti != nullptr) {
		if (tram_rti->UsesOverlay()) {
			SpriteID ground = GetCustomRoadSprite(tram_rti, ti->tile, ROTSG_OVERLAY);
			if (ground != 0) DrawGroundSprite(ground + tram_offset, pal);
		} else if (road_rti != nullptr) {
			DrawGroundSprite(SPR_TRAMWAY_OVERLAY + tram_offset, pal);
		}
	}
}

/**
 * Get ground sprite to draw for a road tile.