Question

所以我一直试图在我身体在世界各地移动的地方移动精灵。所以我使用了精灵的setPosition方法，但事实证明它并没有帮助。我的形象只位于（0,0）位置，我无法理解为什么。

以下是代码：

package com.example.shapetest;

import com.badlogic.gdx.ApplicationListener;
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.Animation;
import com.badlogic.gdx.graphics.g2d.Sprite;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.graphics.g2d.TextureAtlas;
import com.badlogic.gdx.graphics.g2d.TextureRegion;
import com.badlogic.gdx.math.Matrix4;
import com.badlogic.gdx.math.Rectangle;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.physics.box2d.Body;
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.FixtureDef;
import com.badlogic.gdx.physics.box2d.PolygonShape;
import com.badlogic.gdx.physics.box2d.World;

class ShapeTest implements ApplicationListener {

    SpriteBatch batch;
    World world;
    OrthographicCamera camera;
    Box2DDebugRenderer debugRenderer;
    Texture squareTx;
    Sprite square;
    Body body;

    @Override
    public void create() {
        batch = new SpriteBatch();
        world = new World(new Vector2(0,-10),false);
        squareTx = new Texture(Gdx.files.internal("sq.png"));
        square = new Sprite(squareTx);

        debugRenderer = new Box2DDebugRenderer();
        camera = new OrthographicCamera();
        camera.setToOrtho(false);

        BodyDef bd = new BodyDef();
        bd.type = BodyType.DynamicBody;
        bd.position.set(new Vector2((Gdx.graphics.getWidth() / 2) * 0.01f, Gdx.graphics.getHeight() * 0.01f));
        body = world.createBody(bd);
        BodyDef bd2 = new BodyDef();
        bd2.type = BodyType.StaticBody;
        bd2.position.set(new Vector2(Gdx.graphics.getWidth()/2 * 0.01f, 100 * 0.01f));
        Body body2 = world.createBody(bd2);

        square.setSize(100,100);

        PolygonShape shape = new PolygonShape();
        shape.setAsBox(0.5f,0.5f);
        PolygonShape shape2 = new PolygonShape();
        shape2.setAsBox(1.6f,0.3f);

        FixtureDef fd = new FixtureDef();
        fd.density = 1;
        fd.restitution = 0.2f;
        fd.shape = shape;
        fd.friction = 0.4f;

        body.createFixture(fd);
        body2.createFixture(shape2, 0f);

        shape.dispose();
    }

    @Override
    public void resize(int width, int height) {

    }

    @Override
    public void render() {
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

        Vector2 pos = body.getPosition();
        square.setPosition(pos.x ,pos.y);

        camera.update();
                batch.setProjectionMatrix(camera.combined);
        Matrix4 cameraCopy = camera.combined.cpy();
        debugRenderer.render(world, cameraCopy.scl(100f));
        world.step(1/60f,10,10);
        batch.begin();
        square.draw(batch);
        batch.end();
    }

    @Override
    public void pause() {

    }

    @Override
    public void resume() {

    }

    @Override
    public void dispose() {
        batch.dispose();
    }
}

结果如下：

（精灵应该遵循粉红色的盒子位置）

Answer 1

body.getPosition()返回小值，因此对于绘图，您需要将该值转换为像素值。

根据你的说法，精灵大小是100像素，它代表动态物理体，即物理中具有0.5f * 2 = 1;单位的polygonShape，即假设1单位/米的物理等于100像素。

Vector2 pos = body.getPosition();   // value return in physics unit
square.setPosition(pos.x*100 ,pos.y*100);

精灵的setPosition方法不起作用

1 个答案: