runelite-api: add Jarvis march algorithm and and getConvexHull to GameObject

runelite-api/src/main/java/net/runelite/api/GameObject.java

@@ -24,6 +24,12 @@
  */
 package net.runelite.api;
 
+import java.awt.Polygon;
+import java.util.ArrayList;
+import java.util.List;
+import net.runelite.api.model.Jarvis;
+import net.runelite.api.model.Vertex;
+
 /**
  *
  * @author Adam
@@ -55,4 +61,82 @@ public class GameObject extends TileObject
 	{
 		return gameObject.getY();
 	}
+
+	public Renderable getRenderable()
+	{
+		return Renderable.of(gameObject.getRenderable());
+	}
+
+	public Polygon getConvexHull()
+	{
+		Renderable renderable = getRenderable();
+		if (renderable == null)
+		{
+			return null;
+		}
+
+		Model model;
+
+		if (renderable instanceof Model)
+		{
+			model = (Model) renderable;
+		}
+		else
+		{
+			model = renderable.getModel();
+		}
+
+		if (model == null)
+		{
+			return null;
+		}
+
+		int localX = gameObject.getX();
+		int localY = gameObject.getY();
+
+		// models are orientated north (1024) and there are 2048 angles total
+		int orientation = (gameObject.getOrientation() + 1024) % 2048;
+
+		List<Vertex> verticies = model.getVertices();
+
+		if (orientation != 0)
+		{
+			// rotate verticies
+			for (int i = 0; i < verticies.size(); ++i)
+			{
+				Vertex v = verticies.get(i);
+				verticies.set(i, v.rotate(orientation));
+			}
+		}
+
+		List<Point> points = new ArrayList<>();
+
+		for (Vertex v : verticies)
+		{
+			// Compute canvas location of vertex
+			Point p = Perspective.worldToCanvas(client,
+				localX - v.getX(),
+				localY - v.getZ(),
+				-v.getY());
+			if (p != null)
+			{
+				points.add(p);
+			}
+		}
+
+		// Run Jarvis march algorithm
+		points = Jarvis.convexHull(points);
+		if (points == null)
+		{
+			return null;
+		}
+
+		// Convert to a polygon
+		Polygon p = new Polygon();
+		for (Point point : points)
+		{
+			p.addPoint(point.getX(), point.getY());
+		}
+		return p;
+	}
 }

runelite-api/src/main/java/net/runelite/api/model/Jarvis.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2017, Adam <Adam@sigterm.info>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package net.runelite.api.model;
+
+import java.util.ArrayList;
+import java.util.List;
+import net.runelite.api.Point;
+
+/**
+ * Implementation of the Jarvis march algorithm
+ * https://en.wikipedia.org/wiki/Gift_wrapping_algorithm
+ * @author adam
+ */
+public class Jarvis
+{
+	/**
+	 * compute the convex hull of a given set of points
+	 *
+	 * @param points
+	 * @return
+	 */
+	public static List<Point> convexHull(List<Point> points)
+	{
+		if (points.size() < 3)
+		{
+			return null;
+		}
+
+		List<Point> ch = new ArrayList<>();
+
+		// find the left most point
+		Point left = findLeftMost(points);
+
+		// current point we are on
+		Point current = left;
+
+		do
+		{
+			ch.add(current);
+
+			// the next point - all points are to the right of the
+			// line between current and next
+			Point next = null;
+
+			for (Point p : points)
+			{
+				if (next == null)
+				{
+					next = p;
+					continue;
+				}
+
+				int cp = crossProduct(current, p, next);
+				if (cp > 0 || (cp == 0 && current.distanceTo(p) > current.distanceTo(next)))
+				{
+					next = p;
+				}
+			}
+
+			assert next != null;
+
+			assert ch.size() <= points.size() : "hull has more points than graph";
+			current = next;
+		}
+		while (current != left);
+
+		return ch;
+	}
+
+	private static Point findLeftMost(List<Point> points)
+	{
+		Point left = null;
+
+		for (Point p : points)
+		{
+			if (left == null || p.getX() < left.getX())
+			{
+				left = p;
+			}
+			else if (p.getX() == left.getX() && p.getY() < left.getY())
+			{
+				left = p;
+			}
+		}
+
+		return left;
+	}
+
+	private static int crossProduct(Point p, Point q, Point r)
+	{
+		int val = (q.getY() - p.getY()) * (r.getX() - q.getX())
+			- (q.getX() - p.getX()) * (r.getY() - q.getY());
+		return val;
+	}
+}