implement building system

src/lib/config/SurfaceMask.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include <QPoint>
+#include <QSize>
+
+#include "Port.h"
+#include "Rotation.h"
+
+// Parsed representation of a building's surface_mask after applying rotation.
+// All coordinates are relative to the building's anchor tile (the point passed
+// to BuildingSystem::place), which corresponds to (0,0) in this system.
+struct ParsedSurfaceMask
+{
+    QSize footprint;                    // bounding box of body cells (A + S tiles)
+    std::vector<QPoint> bodyCells;      // relative positions of A and S tiles
+    std::vector<Port>   outputPorts;    // port.tile = cell adjacent to body, outside footprint;
+                                        // port.direction = flow direction away from building
+    std::vector<QPoint> shipDockCells;  // relative positions of S tiles (subset of bodyCells)
+};
+
+// Parse a surface_mask definition (as loaded from TOML) and apply the given
+// rotation.  The canonical mask orientation corresponds to Rotation::East.
+// Rotations are applied clockwise (East=0, South=90°, West=180°, North=270°).
+ParsedSurfaceMask parseSurfaceMask(const std::vector<std::string>& rows,
+                                   Rotation rotation);