Question

项目：我一直在使用libgdx-box2d进行一个小项目，其中我想创建一个对象，将其渲染到屏幕并对其应用重力以使其与地面。我目前正在处理的部分是创建和渲染正文。

问题：问题是当我运行项目时，我创建的正文没有显示在屏幕上，我觉得我已经正确创建了正文，因为没有编译问题。< / p>

我尝试了什么：

我尝试了很多东西，例如将圆的半径增加到使它更大（更明显）
通过执行camera = new OrthographicCamera(Gdx.graphics.getWidth() /10, Gdx.graphics.getHeight() /10);来放大屏幕太小了，但无论我尝试我创造的对象是什么无法看到。
将身体的位置更改为不同的x，y位置

我想要的结果：我想要的是可能得到一个答案，为什么我创建的身体没有被显示，并且有一些帮助来渲染它以便可以看到它。我希望我提出的问题的结构清晰且具有信息性。提前谢谢你们提供任何帮助

这是我的相关代码：

package com.mohamed.JungleFighter;

import com.badlogic.gdx.Game;
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.Sprite;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.graphics.g2d.TextureRegion;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.physics.box2d.BodyDef;
import com.badlogic.gdx.physics.box2d.BodyDef.BodyType;
import com.badlogic.gdx.physics.box2d.Box2DDebugRenderer;
import com.badlogic.gdx.physics.box2d.CircleShape;
import com.badlogic.gdx.physics.box2d.Fixture;
import com.badlogic.gdx.physics.box2d.FixtureDef;
import com.badlogic.gdx.physics.box2d.World;
import com.sun.xml.internal.ws.wsdl.writer.document.soap.Body;

//i'm extending libgdx's built in game class which implements the activity listener
public class JungleFighterMain extends Game {

private OrthographicCamera camera;
private SpriteBatch sBatch;
private Texture player;
private Texture enemy;
//private SpriteBatch enemyBatch;
private Sprite sprite1;
private Sprite sprite2;
//just setting my game heighty and width
public static int gameWidth = 1280, gameHeight = 720;
private World world;
private Box2DDebugRenderer debugRenderer;
p 

@Override
public void create () {
    //camera related
camera = new OrthographicCamera(Gdx.graphics.getWidth() /10, Gdx.graphics.getHeight() /10);
                //end of camera related

//BOX2D CODE FOR CREATING WWORLD
    World world = new World(new Vector2(0, -10), true); 

    //creating box2d body definition
    BodyDef bodyDef = new BodyDef();
    //setting body type to dynamic
    bodyDef.type = BodyType.DynamicBody;
    //position
    bodyDef.position.set(0, 0);
    //sending what i just made to the world i created
    // making a circle with a radius of 6

    CircleShape circle = new CircleShape();
    circle.setRadius(30f);

    //making my fixtures for the circle
    FixtureDef fixtureDef = new FixtureDef();
    fixtureDef.shape = circle;
    fixtureDef.density = 0.5f; 
    fixtureDef.friction = 0.4f;
    //making it bounce a little
    fixtureDef.restitution = 0.6f;

    //addding fixture attributes to my ball
    //Fixture fixture = body.createFixture(fixtureDef);

    //end of creating my circle ball 

    //creating my actual ball in the world

    world.createBody(bodyDef).createFixture(fixtureDef);

    circle.dispose();
    //GROUND START

    BodyDef bodyGround = new BodyDef();
    bodyGround.type = BodyType.StaticBody;
    bodyGround.position.set(-100,-100);

    //setting shape of ground

    ChainShape groundShape = new ChainShape();
    groundShape.createChain(new Vector2[] {new Vector2(-250, 0), new Vector2(250, 0)});

    //fixtures for ground
    FixtureDef fixtureDefGround = new FixtureDef();
    fixtureDefGround.shape = groundShape;
    fixtureDefGround.friction = 0.5f;
    fixtureDefGround.restitution = 0;

    world.createBody(bodyGround).createFixture(fixtureDefGround);
    groundShape.dispose();
}

public  void dispose() {
    world.dispose();
}

public void render (float delta) {

    Gdx.gl.glClearColor(0, 0, 0, 1);
    Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
    // camera related
       sBatch.setProjectionMatrix(camera.combined); 

    debugRenderer.render(world, camera.combined);

    world.step(TIMESTEP, VELOCITYITERATIONS, POSITIONITERATIONS);   
    }
}
    public  void resize(int width, int height){
    }

    public  void pause(){
    }

    public  void resume(){
    }
}

Answer 1

在Java中，它不足以声明一个对象，就像你拥有：

private Box2DDebugRenderer debugRenderer

您还需要实例化它，否则它是一个空引用。尝试添加

debugRenderer = new Box2DDebugRenderer()

到您的创建功能，以避免您在评论中提到的错误。构造函数也可能需要一些参数，但我不熟悉Box2D或LibGDX。

Answer 2

经过几个小时的研究后我终于意识到我需要添加camera.viewportHeight =; camera.viewportWidth; camera.position.set（camera.viewportWidth，camera.viewportHeight）; -

使用Libgdx Box2d创建的正文在项目运行时未显示在屏幕上

2 个答案: