185 lines
7.0 KiB
C#
185 lines
7.0 KiB
C#
/* Original source Farseer Physics Engine:
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* Copyright (c) 2014 Ian Qvist, http://farseerphysics.codeplex.com
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* Microsoft Permissive License (Ms-PL) v1.1
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*/
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using System;
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using System.Collections.Generic;
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using FarseerPhysics.Collision.Shapes;
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using FarseerPhysics.Common.Decomposition;
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using FarseerPhysics.Dynamics;
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using FarseerPhysics.Dynamics.Joints;
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using Microsoft.Xna.Framework;
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namespace FarseerPhysics.Common
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{
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/// <summary>
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/// An easy to use manager for creating paths.
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/// </summary>
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public static class PathManager
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{
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#region LinkType enum
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public enum LinkType
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{
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Revolute,
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Slider
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}
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#endregion
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//Contributed by Matthew Bettcher
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/// <summary>
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/// Convert a path into a set of edges and attaches them to the specified body.
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/// Note: use only for static edges.
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/// </summary>
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/// <param name="path">The path.</param>
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/// <param name="body">The body.</param>
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/// <param name="subdivisions">The subdivisions.</param>
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public static void ConvertPathToEdges(Path path, Body body, int subdivisions)
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{
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Vertices verts = path.GetVertices(subdivisions);
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if (path.Closed)
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{
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ChainShape chain = new ChainShape(verts, true);
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body.CreateFixture(chain, Category.Cat1, Category.All);
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}
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else
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{
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for (int i = 1; i < verts.Count; i++)
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{
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body.CreateFixture(new EdgeShape(verts[i], verts[i - 1]), Category.Cat1, Category.All);
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}
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}
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}
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/// <summary>
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/// Convert a closed path into a polygon.
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/// Convex decomposition is automatically performed.
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/// </summary>
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/// <param name="path">The path.</param>
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/// <param name="body">The body.</param>
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/// <param name="density">The density.</param>
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/// <param name="subdivisions">The subdivisions.</param>
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public static void ConvertPathToPolygon(Path path, Body body, float density, int subdivisions)
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{
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if (!path.Closed)
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throw new Exception("The path must be closed to convert to a polygon.");
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List<Vector2> verts = path.GetVertices(subdivisions);
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List<Vertices> decomposedVerts = Triangulate.ConvexPartition(new Vertices(verts), TriangulationAlgorithm.Bayazit);
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foreach (Vertices item in decomposedVerts)
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{
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body.CreateFixture(new PolygonShape(item, density), Category.Cat1, Category.All);
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}
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}
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/// <summary>
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/// Duplicates the given Body along the given path for approximatly the given copies.
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/// </summary>
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/// <param name="world">The world.</param>
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/// <param name="path">The path.</param>
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/// <param name="shapes">The shapes.</param>
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/// <param name="type">The type.</param>
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/// <param name="copies">The copies.</param>
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/// <param name="userData"></param>
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/// <returns></returns>
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public static List<Body> EvenlyDistributeShapesAlongPath(World world, Path path, IEnumerable<Shape> shapes, BodyType type, int copies, object userData = null)
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{
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List<Vector3> centers = path.SubdivideEvenly(copies);
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List<Body> bodyList = new List<Body>();
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for (int i = 0; i < centers.Count; i++)
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{
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Body b = world.CreateBody();
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// copy the type from original body
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b.BodyType = type;
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b.Position = new Vector2(centers[i].X, centers[i].Y);
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b.Rotation = centers[i].Z;
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b.UserData = userData;
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foreach (Shape shape in shapes)
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{
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b.CreateFixture(shape, Category.Cat1, Category.All);
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}
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bodyList.Add(b);
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}
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return bodyList;
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}
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/// <summary>
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/// Duplicates the given Body along the given path for approximatly the given copies.
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/// </summary>
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/// <param name="world">The world.</param>
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/// <param name="path">The path.</param>
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/// <param name="shape">The shape.</param>
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/// <param name="type">The type.</param>
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/// <param name="copies">The copies.</param>
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/// <param name="userData">The user data.</param>
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/// <returns></returns>
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public static List<Body> EvenlyDistributeShapesAlongPath(World world, Path path, Shape shape, BodyType type, int copies, object userData = null)
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{
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List<Shape> shapes = new List<Shape>(1);
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shapes.Add(shape);
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return EvenlyDistributeShapesAlongPath(world, path, shapes, type, copies, userData);
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}
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/// <summary>
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/// Moves the given body along the defined path.
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/// </summary>
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/// <param name="path">The path.</param>
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/// <param name="body">The body.</param>
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/// <param name="time">The time.</param>
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/// <param name="strength">The strength.</param>
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/// <param name="timeStep">The time step.</param>
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public static void MoveBodyOnPath(Path path, Body body, float time, float strength, float timeStep)
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{
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Vector2 destination = path.GetPosition(time);
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Vector2 positionDelta = body.Position - destination;
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Vector2 velocity = (positionDelta / timeStep) * strength;
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body.LinearVelocity = -velocity;
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}
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/// <summary>
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/// Attaches the bodies with revolute joints.
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/// </summary>
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/// <param name="world">The world.</param>
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/// <param name="bodies">The bodies.</param>
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/// <param name="localAnchorA">The local anchor A.</param>
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/// <param name="localAnchorB">The local anchor B.</param>
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/// <param name="connectFirstAndLast">if set to <c>true</c> [connect first and last].</param>
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/// <param name="collideConnected">if set to <c>true</c> [collide connected].</param>
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public static List<RevoluteJoint> AttachBodiesWithRevoluteJoint(World world, List<Body> bodies, Vector2 localAnchorA, Vector2 localAnchorB, bool connectFirstAndLast, bool collideConnected)
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{
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List<RevoluteJoint> joints = new List<RevoluteJoint>(bodies.Count + 1);
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for (int i = 1; i < bodies.Count; i++)
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{
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RevoluteJoint joint = new RevoluteJoint(bodies[i], bodies[i - 1], localAnchorA, localAnchorB);
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joint.CollideConnected = collideConnected;
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world.Add(joint);
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joints.Add(joint);
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}
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if (connectFirstAndLast)
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{
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RevoluteJoint lastjoint = new RevoluteJoint(bodies[0], bodies[bodies.Count - 1], localAnchorA, localAnchorB);
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lastjoint.CollideConnected = collideConnected;
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world.Add(lastjoint);
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joints.Add(lastjoint);
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}
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return joints;
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}
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}
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} |