Java tutorial
package be.ac.ucl.lfsab1509.bouboule.game.physicEditor; /* * This file is part of Bouboule. * * Copyright 2013 UCLouvain * * Authors: * * Group 7 - Course: http://www.uclouvain.be/en-cours-2013-lfsab1509.html * Matthieu Baerts <matthieu.baerts@student.uclouvain.be> * Baptiste Remy <baptiste.remy@student.uclouvain.be> * Nicolas Van Wallendael <nicolas.vanwallendael@student.uclouvain.be> * Helene Verhaeghe <helene.verhaeghe@student.uclouvain.be> * * Bouboule 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/>. */ import com.badlogic.gdx.files.FileHandle; import com.badlogic.gdx.math.Vector2; import com.badlogic.gdx.physics.box2d.Body; import com.badlogic.gdx.physics.box2d.CircleShape; import com.badlogic.gdx.physics.box2d.FixtureDef; import com.badlogic.gdx.physics.box2d.PolygonShape; import com.badlogic.gdx.utils.JsonReader; import com.badlogic.gdx.utils.JsonValue; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; /** * Loads the collision fixtures defined with the Physics Body Editor * application. You only need to give it a body and the corresponding fixture * name, and it will attach these fixtures to your body. * * @author Aurelien Ribon | http://www.aurelienribon.com */ public class BodyEditorLoader { // Model private final Model model; // Reusable stuff private final List<Vector2> vectorPool = new ArrayList<Vector2>(); private final PolygonShape polygonShape = new PolygonShape(); private final CircleShape circleShape = new CircleShape(); private final Vector2 vec = new Vector2(); // ------------------------------------------------------------------------- // Ctors // ------------------------------------------------------------------------- public BodyEditorLoader(FileHandle file) { if (file == null) throw new NullPointerException("file is null"); model = readJson(file.readString()); } public BodyEditorLoader(String str) { if (str == null) throw new NullPointerException("str is null"); model = readJson(str); } // ------------------------------------------------------------------------- // Public API // ------------------------------------------------------------------------- /** * Creates and applies the fixtures defined in the editor. The name * parameter is used to retrieve the right fixture from the loaded file. * <br/><br/> * * The body reference point (the red cross in the tool) is by default * located at the bottom left corner of the image. This reference point * will be put right over the BodyDef position point. Therefore, you should * place this reference point carefully to let you place your body in your * world easily with its BodyDef.position point. Note that to draw an image * at the position of your body, you will need to know this reference point * (see {@link #getOrigin(java.lang.String, float)}. * <br/><br/> * * Also, saved shapes are normalized. As shown in the tool, the width of * the image is considered to be always 1 meter. Thus, you need to provide * a scale factor so the polygons get resized according to your needs (not * every body is 1 meter large in your game, I guess). * * @param body The Box2d body you want to attach the fixture to. * @param name The name of the fixture you want to load. * @param fd The fixture parameters to apply to the created body fixture. * @param scale The desired scale of the body. The default width is 1. */ public void attachFixture(Body body, String name, FixtureDef fd, float scale) { RigidBodyModel rbModel = model.rigidBodies.get(name); if (rbModel == null) throw new RuntimeException("Name '" + name + "' was not found."); Vector2 origin = vec.set(rbModel.origin).scl(scale); for (int i = 0, n = rbModel.polygons.size(); i < n; i++) { PolygonModel polygon = rbModel.polygons.get(i); Vector2[] vertices = polygon.buffer; for (int ii = 0, nn = vertices.length; ii < nn; ii++) { vertices[ii] = newVec().set(polygon.vertices.get(ii)).scl(scale); vertices[ii].sub(origin); } polygonShape.set(vertices); fd.shape = polygonShape; body.createFixture(fd); for (int ii = 0, nn = vertices.length; ii < nn; ii++) { free(vertices[ii]); } } for (int i = 0, n = rbModel.circles.size(); i < n; i++) { CircleModel circle = rbModel.circles.get(i); Vector2 center = newVec().set(circle.center).scl(scale); float radius = circle.radius * scale; circleShape.setPosition(center); circleShape.setRadius(radius); fd.shape = circleShape; body.createFixture(fd); free(center); } } /** * Gets the image path attached to the given name. */ public String getImagePath(String name) { RigidBodyModel rbModel = model.rigidBodies.get(name); if (rbModel == null) throw new RuntimeException("Name '" + name + "' was not found."); return rbModel.imagePath; } /** * Gets the origin point attached to the given name. Since the point is * normalized in [0,1] coordinates, it needs to be scaled to your body * size. Warning: this method returns the same Vector2 object each time, so * copy it if you need it for later use. */ public Vector2 getOrigin(String name, float scale) { RigidBodyModel rbModel = model.rigidBodies.get(name); if (rbModel == null) throw new RuntimeException("Name '" + name + "' was not found."); return vec.set(rbModel.origin).scl(scale); } /** * <b>For advanced users only.</b> Lets you access the internal model of * this loader and modify it. Be aware that any modification is permanent * and that you should really know what you are doing. */ public Model getInternalModel() { return model; } // ------------------------------------------------------------------------- // Json Models // ------------------------------------------------------------------------- public static class Model { public final Map<String, RigidBodyModel> rigidBodies = new HashMap<String, RigidBodyModel>(); } public static class RigidBodyModel { public String name; public String imagePath; public final Vector2 origin = new Vector2(); public final List<PolygonModel> polygons = new ArrayList<PolygonModel>(); public final List<CircleModel> circles = new ArrayList<CircleModel>(); } public static class PolygonModel { public final List<Vector2> vertices = new ArrayList<Vector2>(); private Vector2[] buffer; // used to avoid allocation in attachFixture() } public static class CircleModel { public final Vector2 center = new Vector2(); public float radius; } // ------------------------------------------------------------------------- // Json reading process // ------------------------------------------------------------------------- private Model readJson(String str) { Model m = new Model(); JsonValue map = new JsonReader().parse(str); JsonValue bodyElem = map.getChild("rigidBodies"); for (; bodyElem != null; bodyElem = bodyElem.next()) { RigidBodyModel rbModel = readRigidBody(bodyElem); m.rigidBodies.put(rbModel.name, rbModel); } return m; } private RigidBodyModel readRigidBody(JsonValue bodyElem) { RigidBodyModel rbModel = new RigidBodyModel(); rbModel.name = bodyElem.getString("name"); rbModel.imagePath = bodyElem.getString("imagePath"); JsonValue originElem = bodyElem.get("origin"); rbModel.origin.x = originElem.getFloat("x"); rbModel.origin.y = originElem.getFloat("y"); // polygons JsonValue polygonsElem = bodyElem.getChild("polygons"); for (; polygonsElem != null; polygonsElem = polygonsElem.next()) { PolygonModel polygon = new PolygonModel(); rbModel.polygons.add(polygon); JsonValue vertexElem = polygonsElem.child(); for (; vertexElem != null; vertexElem = vertexElem.next()) { float x = vertexElem.getFloat("x"); float y = vertexElem.getFloat("y"); polygon.vertices.add(new Vector2(x, y)); } polygon.buffer = new Vector2[polygon.vertices.size()]; } // circles JsonValue circleElem = bodyElem.getChild("circles"); for (; circleElem != null; circleElem = circleElem.next()) { CircleModel circle = new CircleModel(); rbModel.circles.add(circle); circle.center.x = circleElem.getFloat("cx"); circle.center.y = circleElem.getFloat("cy"); circle.radius = circleElem.getFloat("r"); } return rbModel; } // ------------------------------------------------------------------------- // Helpers // ------------------------------------------------------------------------- private Vector2 newVec() { return vectorPool.isEmpty() ? new Vector2() : vectorPool.remove(0); } private void free(Vector2 v) { vectorPool.add(v); } }