Initial commit

src/raycast.h

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+/*
+Minetest
+Copyright (C) 2016 juhdanad, Daniel Juhasz <juhdanad@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#pragma once
+
+#include "voxelalgorithms.h"
+#include "util/pointedthing.h"
+
+//! Sorts PointedThings based on their distance.
+struct RaycastSort
+{
+	bool operator() (const PointedThing &pt1, const PointedThing &pt2) const;
+};
+
+//! Describes the state of a raycast.
+class RaycastState
+{
+public:
+	/*!
+	 * Creates a raycast.
+	 * @param objects_pointable if false, only nodes will be found
+	 * @param liquids pointable if false, liquid nodes won't be found
+	 */
+	RaycastState(const core::line3d<f32> &shootline, bool objects_pointable,
+		bool liquids_pointable);
+
+	//! Shootline of the raycast.
+	core::line3d<f32> m_shootline;
+	//! Iterator to store the progress of the raycast.
+	voxalgo::VoxelLineIterator m_iterator;
+	//! Previous tested node during the raycast.
+	v3s16 m_previous_node;
+
+	/*!
+	 * This priority queue stores the found pointed things
+	 * waiting to be returned.
+	 */
+	std::priority_queue<PointedThing, std::vector<PointedThing>, RaycastSort> m_found;
+
+	bool m_objects_pointable;
+	bool m_liquids_pointable;
+
+	//! The code needs to search these nodes around the center node.
+	core::aabbox3d<s16> m_search_range { 0, 0, 0, 0, 0, 0 };
+
+	//! If true, the Environment will initialize this state.
+	bool m_initialization_needed = true;
+};
+
+/*!
+ * Checks if a line and a box intersects.
+ * @param[in]  box              box to test collision
+ * @param[in]  start            starting point of the line
+ * @param[in]  dir              direction and length of the line
+ * @param[out] collision_point  first point of the collision
+ * @param[out] collision_normal normal vector at the collision, points
+ * outwards of the surface. If start is in the box, zero vector.
+ * @returns true if a collision point was found
+ */
+bool boxLineCollision(const aabb3f &box, const v3f &start, const v3f &dir,
+	v3f *collision_point, v3s16 *collision_normal);