所以我确实有一个我不明白的问题。在尝试找出问题所在之后，我决定记录一个video并在此处询问。
在视频中，请注意左上角的True / False布尔值。这是我的变量canJump的值。首先，只需左右移动“ Player”，该值就在true和false之间。当玩家上下倾斜时也会发生这种情况。
使用Tiled创建地图/碰撞层。
我的TiledObject类：
public class TiledObjectUtil {
public static float PPM = 32;
public static void parseTiledObjectLayer(World world, MapObjects objects) {
for(MapObject object : objects) {
Shape shape;
if(object instanceof PolylineMapObject) {
shape = createPolyLine((PolylineMapObject) object);
} else {
continue;
}
Body body;
BodyDef bdef = new BodyDef();
bdef.type = BodyDef.BodyType.StaticBody;
body = world.createBody(bdef);
body.createFixture(shape, 1.0f);
shape.dispose();
}
}
private static ChainShape createPolyLine(PolylineMapObject polyline) {
float[] vertices = polyline.getPolyline().getTransformedVertices();
Vector2[] worldVertices = new Vector2[vertices.length / 2];
for(int i = 0; i<worldVertices.length; i++) {
worldVertices[i] = new Vector2(vertices[i * 2] / PPM, vertices[i*2+1] / PPM);
}
ChainShape cs = new ChainShape();
cs.createChain(worldVertices);
return cs;
}}
和我的播放器类：
public class Player {
private BodyDef def = new BodyDef();
public Body playerBody;
private float speed = 10;
public Player() {
}
public void update() {
if (InputUtil.moveLeft) {
playerBody.setLinearVelocity(-speed, playerBody.getLinearVelocity().y);
}
if (InputUtil.moveRight) {
playerBody.setLinearVelocity(speed, playerBody.getLinearVelocity().y);
}
if (!InputUtil.moveLeft && !InputUtil.moveRight) {
playerBody.setLinearVelocity(0, playerBody.getLinearVelocity().y);
}
}
public void jump() {
if (ContactUtil.canJump) {
playerBody.applyLinearImpulse(0, 80, 0, 0, true);
}
}
public Body createPlayer(World world) {
def.type = BodyDef.BodyType.DynamicBody;
def.position.set(20, 20);
def.fixedRotation = true;
playerBody = world.createBody(def);
PolygonShape shape = new PolygonShape();
shape.setAsBox(2f / 2, 2f / 2);
FixtureDef playerFixture = new FixtureDef();
playerFixture.density = 1f;
playerFixture.shape = shape;
playerFixture.restitution = 0f;
playerFixture.friction = 1f;
playerBody.createFixture(playerFixture);
shape.setAsBox(2f / 2, 1f / 2, new Vector2(0, 0 - 1), 0);
playerFixture.shape = shape;
playerFixture.isSensor = true;
playerBody.createFixture(playerFixture).setUserData("player");
shape.dispose();
return playerBody;
} }
最后，我的ContactListener：
public class ContactUtil implements ContactListener {
public static boolean canJump;
public ContactUtil() {
}
@Override
public void beginContact(Contact contact) {
Fixture fixtureA = contact.getFixtureA();
Fixture fixtureB = contact.getFixtureB();
System.out.println(fixtureA.getUserData() + ", " + fixtureB.getUserData());
if (fixtureA.getUserData() == "player" && fixtureB.getUserData() == null) {
canJump = true;
}
if (fixtureA.getUserData() == null && fixtureB.getUserData() == "player") {
canJump = true;
}
}
@Override
public void endContact(Contact contact) {
Fixture fixtureA = contact.getFixtureA();
Fixture fixtureB = contact.getFixtureB();
System.out.println(fixtureA.getUserData() + ", " + fixtureB.getUserData());
if (fixtureA.getUserData() == "player" && fixtureB.getUserData() == null) {
canJump = false;
}
if (fixtureA.getUserData() == null && fixtureB.getUserData() == "player") {
canJump = false;
}
}
而且，我的播放器每次在斜坡上停下来都会跳一点。我知道是由于以下这一行：
playerBody.setLinearVelocity(0, playerBody.getLinearVelocity().y);如果有人知道更好的方式来处理运动，将不胜感激。
最佳答案
我似乎记得过去有这个确切的问题！我认为问题在于您在beginContact和endContact中的逻辑。
我将用我粗俗的MS Paint技术来解释这个问题。想象以下情况：您的播放器在空中，跌落到下面的平台上。如您所料，canJump为false：
玩家跌落并降落，并调用平台一的beginContact。将canJump设置为true。同样，这是我们所期望的：
现在，玩家向右移动，直到他们与第二平台接触。具有平台2的beginContact被调用。同样，canJump设置为true。
这就是问题所在。在最后一步，玩家仍与平台一保持联系。但是现在它们还不是，所以调用平台1的endContact。 canJump现在设置为false。这解释了您得到的意外行为。
解决方案非常简单。您需要维护播放器底部正在接触的联系人列表。在此iforce2d文章中，有一个指南可以准确地做到这一点：http://www.iforce2d.net/b2dtut/jumpability
祝好运！