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engines/sword25/math/region.h

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+/*
+ * This code is based on Broken Sword 2.5 engine
+ *
+ * Copyright (c) Malte Thiesen, Daniel Queteschiner and Michael Elsdoerfer
+ *
+ * Licensed under GNU GPL v2
+ *
+ */
+
+#ifndef SWORD25_REGION_H
+#define SWORD25_REGION_H
+
+#include "sword25/kernel/common.h"
+#include "sword25/kernel/persistable.h"
+#include "sword25/math/vertex.h"
+#include "sword25/math/polygon.h"
+#include "common/rect.h"
+
+namespace Sword25 {
+
+/**
+ * This class is the base class of all regions.
+ *
+ * The IsValid() method can be queried to see whether the object is in a valid state.
+ * If this is not the case, the method Init() is the only method that may be invoked.
+ * This class guarantees that the Vertecies outline of the hole, and the polygons are
+ * arranged in a clockwise direction, so that the polygon working algorithms will
+ * work properly.
+ */
+class Region : public Persistable {
+protected:
+	/**
+	 * Creates a new BS_Region object
+	 *
+	 * After creation the object is invaild (IsValid() return false), but a call can
+	 * be made later on to Init() to set up the region into a valid state.
+	 */
+	Region();
+
+	Region(InputPersistenceBlock &reader, uint handle);
+
+public:
+	enum REGION_TYPE {
+		RT_REGION,
+		RT_WALKREGION
+	};
+
+	static uint create(REGION_TYPE type);
+	static uint create(InputPersistenceBlock &reader, uint handle = 0);
+
+	~Region() override;
+
+	/**
+	 * Initializes a BS_Region object
+	 * @param Contour       A polygon indicating the outline of the region
+	 * @param pHoles        A pointer to an array of polygons representing the hole state in the region.
+	 * If the region has no holes, it must be passed as NULL. The default value is NULL.
+	 * @return              Returns true if the initialisation was successful, otherwise false.
+	 * @remark              If the region was already initialized, the old state will be deleted.
+	 */
+	virtual bool init(const Polygon &contour, const Common::Array<Polygon> *pHoles = NULL);
+
+	//
+	// Exploratory Methods
+	//
+
+	/**
+	 * Specifies whether the object is in a valid state
+	 * @return              Returns true if the object is in a valid state, otherwise false.
+	 * @remark              Invalid objects can be made valid by calling Init with a valid state.
+	 */
+	bool isValid() const {
+		return _valid;
+	}
+
+	/**
+	 * Returns the position of the region
+	 */
+	const Vertex &getPosition() const {
+		return _position;
+	}
+
+	/**
+	 * Returns the X position of the region
+	 */
+	int getPosX() const {
+		return _position.x;
+	}
+
+	/**
+	 * Returns the Y position of the region
+	 */
+	int getPosY() const {
+		return _position.y;
+	}
+
+	/**
+	 * Indicates whether a point is inside the region
+	 * @param Vertex        A verex with the co-ordinates of the test point
+	 * @return              Returns true if the point is within the region, otherwise false.
+	 */
+	bool isPointInRegion(const Vertex &vertex) const;
+
+	/**
+	 * Indicates whether a point is inside the region
+	 * @param X             The X position
+	 * @param Y             The Y position
+	 * @return              Returns true if the point is within the region, otherwise false.
+	 */
+	bool isPointInRegion(int x, int y) const;
+
+	/**
+	 * Returns the countour of the region
+	 */
+	const Polygon &getContour() const {
+		return _polygons[0];
+	}
+
+	/**
+	 * Returns the number of polygons in the hole region
+	 */
+	int getHoleCount() const {
+		return static_cast<int>(_polygons.size() - 1);
+	}
+
+	/**
+	 * Returns a specific hole polygon in the region
+	 * @param i             The number of the hole to return.
+	 * The index must be between 0 and GetHoleCount() - 1.
+	 * @return              Returns the desired hole polygon
+	 */
+	inline const Polygon &getHole(uint i) const;
+
+	/**
+	 * For a point outside the region, finds the closest point inside the region
+	 * @param Point         The point that is outside the region
+	 * @return              Returns the point within the region which is closest
+	 * @remark              This method does not always work with pixel accuracy.
+	 * One should not therefore rely on the fact that there is really no point in
+	 * the region which is closer to the given point.
+	 */
+	Vertex findClosestRegionPoint(const Vertex &point) const;
+
+	/**
+	 * Returns the centroid for the region
+	 */
+	Vertex getCentroid() const;
+
+	bool isLineOfSight(const Vertex &a, const Vertex &b) const;
+
+	//
+	// Manipulation Methods
+	//
+
+	/**
+	 * Sets the position of the region
+	 * @param X             The new X psoition of the region
+	 * @param Y             The new Y psoition of the region
+	 */
+	virtual void setPos(int x, int y);
+
+	/**
+	 * Sets the X position of the region
+	 * @param X             The new X position of the region
+	 */
+	void setPosX(int x);
+
+	/**
+	 * Sets the Y position of the region
+	 * @param Y             The new Y position of the region
+	 */
+	void setPosY(int y);
+
+	//
+	// Manipulation Methods
+	//
+
+	bool persist(OutputPersistenceBlock &writer) override;
+	bool unpersist(InputPersistenceBlock &reader) override;
+
+protected:
+	/// This specifies the type of object
+	REGION_TYPE _type;
+	/// This variable indicates whether the current object state is valid
+	bool _valid;
+	/// This vertex is the position of the region
+	Vertex _position;
+	/// This array contains all the polygons that define the region. The first element of
+	// the array is the contour, all others are the holes
+	Common::Array<Polygon> _polygons;
+	/// The bounding box for the region
+	Common::Rect _boundingBox;
+
+	/**
+	 * Updates the bounding box of the region.
+	 */
+	void updateBoundingBox();
+
+	/**
+	 * Find the point on a line which is closest to another point
+	 * @param LineStart     The start of the line
+	 * @param LineEnd       The end of the line
+	 * @param Point         The point to be compared against
+	 * @return              Returns the point on the line which is cloest to the passed point.
+	 */
+	Vertex findClosestPointOnLine(const Vertex &lineStart, const Vertex &lineEnd, const Vertex point) const;
+};
+
+inline const Polygon &Region::getHole(uint i) const {
+	assert(i < _polygons.size() - 1);
+	return _polygons[i + 1];
+}
+
+} // End of namespace Sword25
+
+#endif