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Physical madness

Good afternoon, dear reader! I, a novice Java programmer, for a long time could not get used to the Box2D library. First, because it is written for C ++, and there is no documentation for it, and I do not know the C syntax. Secondly, due to the fact that detailed lessons on this library is only as an extension of libGDX. After a couple of weeks of hard struggle, I was finally able to understand how to work with this library, and in this article I will tell about it (and show it).

I work in Eclipse , the article will be related to this development environment. First, download the libGDX collector and make a standard build. We need a Desktop application with the extension Box2D. Then go to Eclipse, click File → Import → Gradle → Gradle Project and specify the path to your build.

Here is an image with a demonstration of how mine looks. I added the Utils package to the Core folder with the class Constants, which contains only one constant - the number of pixels per meter. This is so that the world is not gigantic.

image

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Here is the code for the DesktopLauncher class from the com.mygdx.game.desktop package:

Paste this code into the class and forget about it.
package com.mygdx.game.desktop; import com.badlogic.gdx.backends.lwjgl.LwjglApplication; import com.badlogic.gdx.backends.lwjgl.LwjglApplicationConfiguration; import com.mygdx.game.MyGdxGame; public class DesktopLauncher { public static void main(String[] arg) { LwjglApplicationConfiguration config = new LwjglApplicationConfiguration(); //   config.width = 720; //   config.height = 480; config.backgroundFPS = 60; config.foregroundFPS = 60; new LwjglApplication(new MyGdxGame(), config); } }


There will be a lot of code, so I will put it on spoilers. Only the MyGdxGame class from the com.mygdx.game package is modified.

So, let's try to do a pretty simple thing in our application. The way the ball crashes into a wall of plates, and they fly away. Something like:

image


Idea 1. Bowling
 package com.mygdx.game; import com.badlogic.gdx.ApplicationAdapter; import com.badlogic.gdx.Gdx; import com.badlogic.gdx.Input.Keys; import com.badlogic.gdx.graphics.GL20; import com.badlogic.gdx.graphics.OrthographicCamera; import com.badlogic.gdx.graphics.Texture; import com.badlogic.gdx.graphics.g2d.SpriteBatch; import com.badlogic.gdx.math.Vector2; import com.badlogic.gdx.math.Vector3; import com.badlogic.gdx.physics.box2d.Body; import com.badlogic.gdx.physics.box2d.BodyDef; import com.badlogic.gdx.physics.box2d.Box2DDebugRenderer; import com.badlogic.gdx.physics.box2d.CircleShape; import com.badlogic.gdx.physics.box2d.PolygonShape; import com.badlogic.gdx.physics.box2d.World; import utils.Constants; public class MyGdxGame extends ApplicationAdapter { SpriteBatch batch; Texture img; private OrthographicCamera camera; private boolean DEBUG = false; private World world; private Body ball; private Body floor; private Body wall; private Body verticals; private Body horizontals; private Box2DDebugRenderer b2dr; //        public void create() { float w = Gdx.graphics.getWidth(); float h = Gdx.graphics.getHeight(); camera = new OrthographicCamera(); camera.setToOrtho(false, w / 2, h / 2); world = new World(new Vector2(0, -9.8f), false); //      b2dr = new Box2DDebugRenderer(); //    ball = createPlayer(); //   "",     floor = createfloor(); //    verticals = createverticals(80, 80); verticals = createverticals(100, 80); verticals = createverticals(120, 80); verticals = createverticals(90, 111); verticals = createverticals(110, 111); verticals = createverticals(100, 141); horizontals = createhorizontals(85, 95); horizontals = createhorizontals(115, 95); horizontals = createhorizontals(100, 126); //   - wall = createwall(430, 170); wall = createwall(-430, 170); } public void render() { update(Gdx.graphics.getDeltaTime()); //    Gdx.gl.glClearColor(0, 0, 0, 1); Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT); b2dr.render(world, camera.combined.scl(Constants.PPM)); } public void resize(int width, int height) { camera.setToOrtho(false, width / 2, height / 2); } public void dispose() { world.dispose(); b2dr.dispose(); } //     public void update(float delta) { world.step(1 / 60f, 6, 2); inputUpdate(delta); cameraUpdate(delta); } //     public void inputUpdate(float delta) { int HF = 0; if (Gdx.input.isKeyPressed(Keys.SPACE)) { HF = 5; } ball.setLinearVelocity(HF * 5, ball.getLinearVelocity().y); } //      public void cameraUpdate(float delta) { Vector3 position = camera.position; position.x = ball.getPosition().x * Constants.PPM; position.y = ball.getPosition().y * Constants.PPM; camera.position.set(position); camera.update(); } //  ,     ,   , // ,  . //     public Body createPlayer() { Body pBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.DynamicBody; def.position.set(20 / Constants.PPM, 90 / Constants.PPM); def.fixedRotation = false; pBody = world.createBody(def); CircleShape shape = new CircleShape(); shape.setRadius(10 / Constants.PPM); pBody.createFixture(shape, 1.0f); def.bullet = true; shape.dispose(); return pBody; } //     public Body createfloor() { Body fBody; BodyDef def = new BodyDef(); //   def.type = BodyDef.BodyType.StaticBody; //  def.position.set(0, 0); //   def.fixedRotation = true; fBody = world.createBody(def); PolygonShape shape = new PolygonShape(); //   shape.setAsBox(480 / Constants.PPM, 70 / Constants.PPM); fBody.createFixture(shape, 0.001f); shape.dispose(); return fBody; } //     public Body createwall(int xo, int yo) { Body fBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.StaticBody; def.position.set(xo / Constants.PPM, yo / Constants.PPM); def.fixedRotation = true; fBody = world.createBody(def); PolygonShape shape = new PolygonShape(); shape.setAsBox(50 / Constants.PPM, 100 / Constants.PPM); fBody.createFixture(shape, 0.001f); shape.dispose(); return fBody; } //   public Body createverticals(int xo, int xy) { Body fBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.DynamicBody; def.position.set(xo / Constants.PPM, xy / Constants.PPM); def.fixedRotation = false; fBody = world.createBody(def); PolygonShape shape = new PolygonShape(); shape.setAsBox(5 / Constants.PPM, 10 / Constants.PPM); fBody.createFixture(shape, 1.0f); def.bullet = true; shape.dispose(); return fBody; } //   public Body createhorizontals(int xo, int xy) { Body fBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.DynamicBody; def.position.set(xo / Constants.PPM, xy / Constants.PPM); def.fixedRotation = false; fBody = world.createBody(def); PolygonShape shape = new PolygonShape(); shape.setAsBox(13 / Constants.PPM, 5 / Constants.PPM); fBody.createFixture(shape, 1.0f); def.bullet = true; shape.dispose(); return fBody; } }


It turned out great, right? By changing several parameters, you can achieve exactly what you need! And do not write so many lines of code.

But now I want to see the elastic impact. And let the objects on the stage be bigger. We get the following result:

image

And here is the code:
 package com.mygdx.game; import com.badlogic.gdx.ApplicationAdapter; import com.badlogic.gdx.Gdx; import com.badlogic.gdx.physics.box2d.FixtureDef; import com.badlogic.gdx.graphics.GL20; import com.badlogic.gdx.graphics.OrthographicCamera; import com.badlogic.gdx.graphics.Texture; import com.badlogic.gdx.graphics.g2d.SpriteBatch; import com.badlogic.gdx.math.Vector2; import com.badlogic.gdx.math.Vector3; import com.badlogic.gdx.physics.box2d.Body; import com.badlogic.gdx.physics.box2d.BodyDef; import com.badlogic.gdx.physics.box2d.Box2DDebugRenderer; import com.badlogic.gdx.physics.box2d.CircleShape; import com.badlogic.gdx.physics.box2d.PolygonShape; import com.badlogic.gdx.physics.box2d.World; import utils.Constants; public class MyGdxGame extends ApplicationAdapter { SpriteBatch batch; Texture img; private OrthographicCamera camera; private boolean DEBUG = false; private World world; private Body ball; private Body floor; private Body wall; private Body verticals; private Body horizontals; private Box2DDebugRenderer b2dr; public void create() { float w = Gdx.graphics.getWidth(); float h = Gdx.graphics.getHeight(); camera = new OrthographicCamera(); camera.setToOrtho(false, w / 2, h / 2); world = new World(new Vector2(0, -9.8f), false); b2dr = new Box2DDebugRenderer(); //   ball = createPlayer(); //   floor = createfloor(); wall = createwall(100, 170); wall = createwall(-60, 170); //   .   ,   verticals = createverticals(5, 50); verticals = createverticals(10, 50); verticals = createverticals(15, 50); verticals = createverticals(20, 50); verticals = createverticals(25, 50); verticals = createverticals(30, 50); verticals = createverticals(35, 50); verticals = createverticals(5, 55); verticals = createverticals(10, 55); verticals = createverticals(15, 55); verticals = createverticals(20, 55); verticals = createverticals(25, 55); verticals = createverticals(30, 55); verticals = createverticals(35, 55); verticals = createverticals(5, 60); verticals = createverticals(10, 60); verticals = createverticals(15, 60); verticals = createverticals(20, 60); verticals = createverticals(25, 60); verticals = createverticals(30, 60); verticals = createverticals(35, 60); verticals = createverticals(5, 70); verticals = createverticals(10, 70); verticals = createverticals(15, 70); verticals = createverticals(20, 70); verticals = createverticals(25, 70); verticals = createverticals(30, 70); verticals = createverticals(35, 70); verticals = createverticals(5, 80); verticals = createverticals(10, 80); verticals = createverticals(15, 80); verticals = createverticals(20, 80); verticals = createverticals(25, 80); verticals = createverticals(30, 80); verticals = createverticals(35, 80); } public void render() { update(Gdx.graphics.getDeltaTime()); Gdx.gl.glClearColor(0, 0, 0, 1); Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT); b2dr.render(world, camera.combined.scl(Constants.PPM)); } public void resize(int width, int height) { camera.setToOrtho(false, width / 2, height / 2); } public void dispose() { world.dispose(); b2dr.dispose(); } public void update(float delta) { world.step(1 / 60f, 6, 2); inputUpdate(delta); cameraUpdate(delta); } //    public void inputUpdate(float delta) { ball.setAngularVelocity(3.0f); } public void cameraUpdate(float delta) { Vector3 position = camera.position; position.x = ball.getPosition().x * Constants.PPM; position.y = ball.getPosition().y * Constants.PPM; camera.position.set(position); camera.update(); } //   public Body createPlayer() { Body pBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.DynamicBody; def.position.set(20 / Constants.PPM, 800 / Constants.PPM); def.fixedRotation = false; pBody = world.createBody(def); CircleShape shape = new CircleShape(); shape.setRadius(10 / Constants.PPM); pBody.createFixture(shape, 1.0f); def.bullet = true; shape.dispose(); return pBody; } //   public Body createfloor() { Body fBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.StaticBody; def.position.set(0, 0); def.fixedRotation = true; fBody = world.createBody(def); PolygonShape shape = new PolygonShape(); shape.setAsBox(480 / Constants.PPM, 70 / Constants.PPM); fBody.createFixture(shape, 0.001f); shape.dispose(); return fBody; } //   public Body createwall(int xo, int yo) { Body fBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.StaticBody; def.position.set(xo / Constants.PPM, yo / Constants.PPM); def.fixedRotation = true; fBody = world.createBody(def); PolygonShape shape = new PolygonShape(); shape.setAsBox(50 / Constants.PPM, 100 / Constants.PPM); fBody.createFixture(shape, 0.001f); shape.dispose(); return fBody; } //      public Body createverticals(int xo, int yo) { Body pBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.DynamicBody; def.position.set(xo / Constants.PPM, yo / Constants.PPM); def.fixedRotation = false; pBody = world.createBody(def); CircleShape shape = new CircleShape(); shape.setRadius(2 / Constants.PPM); //     FixtureDef fd = new FixtureDef(); //  fd.restitution = 1.0f; //  fd.density = 5.0f; //  fd.friction = 0.01f; fd.shape = shape; pBody.createFixture(fd); def.bullet = true; shape.dispose(); return pBody; } }


Creating a cart in Box2D is not easy. It is necessary to bind the bodies so that they move as one unit. The following gif shows only the essence.

image


How did it happen?
 package com.mygdx.game; import com.badlogic.gdx.ApplicationAdapter; import com.badlogic.gdx.Gdx; import com.badlogic.gdx.Input; import com.badlogic.gdx.graphics.GL20; import com.badlogic.gdx.graphics.OrthographicCamera; import com.badlogic.gdx.graphics.Texture; import com.badlogic.gdx.graphics.g2d.SpriteBatch; import com.badlogic.gdx.math.Vector2; import com.badlogic.gdx.math.Vector3; import com.badlogic.gdx.physics.box2d.Body; import com.badlogic.gdx.physics.box2d.BodyDef; import com.badlogic.gdx.physics.box2d.Box2DDebugRenderer; import com.badlogic.gdx.physics.box2d.CircleShape; import com.badlogic.gdx.physics.box2d.PolygonShape; import com.badlogic.gdx.physics.box2d.World; import utils.Constants; public class MyGdxGame extends ApplicationAdapter { SpriteBatch batch; Texture img; private OrthographicCamera camera; private boolean DEBUG = false; private World world; private Body ball; private Body ball1; private Body floor; private Body wall; private Body verticals; private Body horizontals; private Box2DDebugRenderer b2dr; public void create() { float w = Gdx.graphics.getWidth(); float h = Gdx.graphics.getHeight(); camera = new OrthographicCamera(); camera.setToOrtho(false, w / 2, h / 2); world = new World(new Vector2(0, -9.8f), false); b2dr = new Box2DDebugRenderer(); //   ball = createPlayer(20 / Constants.PPM, 70 / Constants.PPM); ball1 = createPlayer(50 / Constants.PPM, 70 / Constants.PPM); floor = createfloor(); wall = createwall(430, 170); wall = createwall(-430, 170); verticals = createverticals(); } public void render() { update(Gdx.graphics.getDeltaTime()); Gdx.gl.glClearColor(0, 0, 0, 1); Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT); b2dr.render(world, camera.combined.scl(Constants.PPM)); } public void resize(int width, int height) { camera.setToOrtho(false, width / 2, height / 2); } public void dispose() { world.dispose(); b2dr.dispose(); } public void update(float delta) { world.step(1 / 60f, 6, 2); inputUpdate(delta); cameraUpdate(delta); } public void inputUpdate(float delta) { //   .         ball.setLinearVelocity(3.0f, ball.getLinearVelocity().y); ball1.setLinearVelocity(3.0f, ball.getLinearVelocity().y); verticals.setLinearVelocity(3.0f, verticals.getLinearVelocity().y); } public void cameraUpdate(float delta) { Vector3 position = camera.position; position.x = ball.getPosition().x * Constants.PPM; position.y = ball.getPosition().y * Constants.PPM; camera.position.set(position); camera.update(); } //   public Body createPlayer(float xo, float yo) { Body pBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.DynamicBody; def.position.set(xo, yo); def.fixedRotation = false; pBody = world.createBody(def); CircleShape shape = new CircleShape(); shape.setRadius(10 / Constants.PPM); pBody.createFixture(shape, 1.0f); def.bullet = true; shape.dispose(); return pBody; } public Body createfloor() { Body fBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.StaticBody; def.position.set(0, 0); def.fixedRotation = true; fBody = world.createBody(def); PolygonShape shape = new PolygonShape(); shape.setAsBox(480 / Constants.PPM, 70 / Constants.PPM); fBody.createFixture(shape, 0.001f); shape.dispose(); return fBody; } public Body createwall(int xo, int yo) { Body fBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.StaticBody; def.position.set(xo / Constants.PPM, yo / Constants.PPM); def.fixedRotation = true; fBody = world.createBody(def); PolygonShape shape = new PolygonShape(); shape.setAsBox(50 / Constants.PPM, 100 / Constants.PPM); fBody.createFixture(shape, 0.001f); shape.dispose(); return fBody; } //   public Body createverticals() { Body fBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.DynamicBody; def.position.set(30 / Constants.PPM, 90 / Constants.PPM); def.fixedRotation = true; fBody = world.createBody(def); PolygonShape shape = new PolygonShape(); shape.setAsBox(30 / Constants.PPM, 3 / Constants.PPM); fBody.createFixture(shape, 0.001f); shape.dispose(); return fBody; } }


If you look at the code, you will notice that this is not a real cart, but rather a stick on wheels. Come on, enthusiasts! On Youtube there is a video where a four-stroke ICE was made in Box2D. Are we worse? Waiting for your successes in the comments!

image


More collisions!
 package com.mygdx.game; import com.badlogic.gdx.ApplicationAdapter; import com.badlogic.gdx.Gdx; import com.badlogic.gdx.graphics.GL20; import com.badlogic.gdx.graphics.OrthographicCamera; import com.badlogic.gdx.graphics.Texture; import com.badlogic.gdx.graphics.g2d.SpriteBatch; import com.badlogic.gdx.math.Vector2; import com.badlogic.gdx.math.Vector3; import com.badlogic.gdx.physics.box2d.Body; import com.badlogic.gdx.physics.box2d.BodyDef; import com.badlogic.gdx.physics.box2d.Box2DDebugRenderer; 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.physics.box2d.World; import utils.Constants; public class MyGdxGame extends ApplicationAdapter { SpriteBatch batch; Texture img; private OrthographicCamera camera; private boolean DEBUG = false; private World world; private Body ball; private Body ball1; private Body ball2; private Body ball3; private Body ball4; private Body ball5; private Body floor; private Body wall; private Body verticals; private Body horizontals; private Box2DDebugRenderer b2dr; public void create() { float w = Gdx.graphics.getWidth(); float h = Gdx.graphics.getHeight(); camera = new OrthographicCamera(); camera.setToOrtho(false, w / 2, h / 2); world = new World(new Vector2(0, -9.8f), false); b2dr = new Box2DDebugRenderer(); //      ball = createPlayer(20 / Constants.PPM, 150 / Constants.PPM); ball1 = createPlayer(35 / Constants.PPM, 200 / Constants.PPM); ball2 = createPlayer(35 / Constants.PPM, 300 / Constants.PPM); ball3 = createPlayer(20 / Constants.PPM, 400 / Constants.PPM); ball4 = createPlayer(35 / Constants.PPM, 200 / Constants.PPM); ball5 = createPlayer(45 / Constants.PPM, 500 / Constants.PPM); floor = createfloor(); wall = createwall(100, 170); wall = createwall(-60, 170); } public void render() { update(Gdx.graphics.getDeltaTime()); Gdx.gl.glClearColor(0, 0, 0, 1); Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT); b2dr.render(world, camera.combined.scl(Constants.PPM)); } public void resize(int width, int height) { camera.setToOrtho(false, width / 2, height / 2); } public void dispose() { world.dispose(); b2dr.dispose(); } public void update(float delta) { world.step(1 / 60f, 6, 2); cameraUpdate(delta); } public void cameraUpdate(float delta) { Vector3 position = camera.position; position.x = ball.getPosition().x * Constants.PPM; position.y = ball.getPosition().y * Constants.PPM; camera.position.set(position); camera.update(); } public Body createPlayer(float xo, float yo) { Body pBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.DynamicBody; def.position.set(xo, yo); def.fixedRotation = false; pBody = world.createBody(def); CircleShape shape = new CircleShape(); shape.setRadius(10 / Constants.PPM); pBody.createFixture(shape, 0.0001f); def.bullet = true; // ,      FixtureDef fd = new FixtureDef(); fd.restitution = 1.0f; fd.density = 5.0f; fd.friction = 0.01f; fd.shape = shape; pBody.createFixture(fd); shape.dispose(); return pBody; } public Body createfloor() { Body fBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.StaticBody; def.position.set(0, 0); def.fixedRotation = true; fBody = world.createBody(def); PolygonShape shape = new PolygonShape(); shape.setAsBox(480 / Constants.PPM, 70 / Constants.PPM); fBody.createFixture(shape, 0.001f); shape.dispose(); return fBody; } public Body createwall(int xo, int yo) { Body fBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.StaticBody; def.position.set(xo / Constants.PPM, yo / Constants.PPM); def.fixedRotation = true; fBody = world.createBody(def); PolygonShape shape = new PolygonShape(); shape.setAsBox(50 / Constants.PPM, 100 / Constants.PPM); fBody.createFixture(shape, 0.001f); shape.dispose(); return fBody; } }


And the last gif for today. The inclined plane is familiar to us from the lessons of physics. This code presents how to get a more complex form (theoretically arbitrary) in order to open endless possibilities for game physics.

image

Inclined plane
 public class MyGdxGame extends ApplicationAdapter { SpriteBatch batch; Texture img; private OrthographicCamera camera; private boolean DEBUG = false; private World world; private Body ball; private Body floor; private Body wall; private Body plos; private Body verticals; private Body horizontals; private Box2DDebugRenderer b2dr; public void create() { float w = Gdx.graphics.getWidth(); float h = Gdx.graphics.getHeight(); camera = new OrthographicCamera(); camera.setToOrtho(false, w / 2, h / 2); world = new World(new Vector2(0, -9.8f), false); b2dr = new Box2DDebugRenderer(); ball = createPlayer(); floor = createfloor(); wall = createwall(430, 170); wall = createwall(-430, 170); plos = createplos(); } public void render() { update(Gdx.graphics.getDeltaTime()); Gdx.gl.glClearColor(0, 0, 0, 1); Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT); b2dr.render(world, camera.combined.scl(Constants.PPM)); } public void resize(int width, int height) { camera.setToOrtho(false, width / 2, height / 2); } public void dispose() { world.dispose(); b2dr.dispose(); } public void update(float delta) { world.step(1 / 60f, 6, 2); cameraUpdate(delta); } public void cameraUpdate(float delta) { Vector3 position = camera.position; position.x = ball.getPosition().x * Constants.PPM; position.y = ball.getPosition().y * Constants.PPM; camera.position.set(position); camera.update(); } public Body createPlayer() { Body pBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.DynamicBody; def.position.set(30 / Constants.PPM, 190 / Constants.PPM); def.fixedRotation = false; pBody = world.createBody(def); CircleShape shape = new CircleShape(); shape.setRadius(10 / Constants.PPM); pBody.createFixture(shape, 1.0f); def.bullet = true; shape.dispose(); return pBody; } public Body createfloor() { Body fBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.StaticBody; def.position.set(0, 0); def.fixedRotation = true; fBody = world.createBody(def); PolygonShape shape = new PolygonShape(); shape.setAsBox(480 / Constants.PPM, 70 / Constants.PPM); fBody.createFixture(shape, 0.001f); shape.dispose(); return fBody; } public Body createwall(int xo, int yo) { Body fBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.StaticBody; def.position.set(xo / Constants.PPM, yo / Constants.PPM); def.fixedRotation = true; fBody = world.createBody(def); PolygonShape shape = new PolygonShape(); shape.setAsBox(50 / Constants.PPM, 100 / Constants.PPM); fBody.createFixture(shape, 0.001f); shape.dispose(); return fBody; } public Body createplos() { Vector2[] vertices = new Vector2[3]; vertices[0] = new Vector2(0f , -0.6f ); vertices[1] = new Vector2(1f , -0.6f ); vertices[2] = new Vector2(1f , 1f); PolygonShape shape = new PolygonShape(); Body fBody; BodyDef def = new BodyDef(); def.type = BodyDef.BodyType.StaticBody; def.position.set(20 / Constants.PPM, 90 / Constants.PPM); def.fixedRotation = true; fBody = world.createBody(def); shape.set(vertices); fBody.createFixture(shape, 0.001f); shape.dispose(); return fBody; } }


I hope that thanks to this code you will be able to understand the basics of Box2D, and only excellent applications will be born! Thank you for reading to the end! I will try to answer all the questions in the comments!

Source: https://habr.com/ru/post/450272/

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