Question

enter image description here

简而言之，我的问题是如何连接复杂的2个多边形形状并对其进行纹理化。

这是关于我的问题的信息：
我有b2WeldJointDef的问题，附加2 b2body的但是当我开始调试e_jointBit打开。这是我的代码，我附上了图片

![b2BodyDef bodyDef;
bodyDef.position.Set((screenSize.width/2.0)/PTM_RATIO,(screenSize.height/2.0)/PTM_RATIO);
//CCLOGWARN("position:pX:%f pY:%f",pX,pY);
bodyDef.type=b2_dynamicBody;
bodyDef.userData = sprite;     
bodyDef.linearDamping = 1.0;
bodyDef.angularDamping = 1.0;
b2FixtureDef* fixtureDef=new b2FixtureDef();
fixtureDef->density=3.0;
fixtureDef->restitution=0.0;
fixtureDef->friction=1.0;
fixtureDef->filter.groupIndex=-1;
b2Body* car_body = world->CreateBody(&bodyDef);

// here i build the custom polygons to form complex body 
polygonShape = new b2PolygonShape();
b2Vec2 *vertices = new b2Vec2\[10\];
// setting the vertices all working great : 
...
...
...
polygonShape->Set(vertices,10);
fixtureDef->shape = polygonShape;
car_body->CreateFixture(fd);



// --------  trying to attach the axle to the main car buy 


b2BodyDef axlecontainerBodyDef;
axlecontainerBodyDef.userData = axlecontainerSprite;
axlecontainerBodyDef.type=b2_dynamicBody;
axlecontainerBodyDef.position.Set(((screenSize.width/2.0))/PTM_RATIO,(screenSize.height/2.0)/PTM_RATIO);
b2Body* axlecontainerBody = world->CreateBody(&axlecontainerBodyDef);

b2FixtureDef * axleContainerFixture = new b2FixtureDef();
axleContainerFixture->density=3.0;       
axleContainerFixture->friction=0.0;
axleContainerFixture->restitution=1.0;
axleContainerFixture->filter.groupIndex=-1;  

//LEFT AXLE CONTAINER 
// here i build the custom polygons to form complex new body to be attached to the main car body
polygonShape = new b2PolygonShape();
b2Vec2 *vertices = new b2Vec2\[10\];
// setting the vertices all working great : 
...
...
...
polygonShape->Set(vertices,10);
axleContainerFixture->shape = polygonShape;
axlecontainerBody->CreateFixture(fd);


b2WeldJointDef *weldJointDef = new b2WeldJointDef();

weldJointDef->bodyA=axlecontainerBody;
weldJointDef->bodyB=body;
float x = body->GetWorldCenter().x/PTM_RATIO;
float y = body->GetWorldCenter().y/PTM_RATIO;
weldJointDef->localAnchorA.Set(-0.5, -0.3);
weldJointDef->localAnchorB.Set(-0.5, -0.3);
weldJointDef->referenceAngle = 0* M_PI /3;
//weldJointDef->collideConnected = false;
world->CreateJoint(weldJointDef);][2]

现在你可以在附图中看到焊点不在正确的位置，我究竟做错了什么？或者你对这个使用焊接接头有什么看法？这是正确的方法吗？

更新
在一遍又一遍地阅读和更改代码后，我仍然可以使事情发挥作用我需要jonits仍然错过了：这是我的固定代码，因为你可以看到它从车身上取下车身的中心：

 b2BodyDef bodyDef;
    bodyDef.position.Set((screenSize.width/2.0)/PTM_RATIO,(screenSize.height/2.0)/PTM_RATIO);    
    bodyDef.type=b2_dynamicBody;
    bodyDef.userData = sprite;     
    bodyDef.linearDamping = 1.0;
    bodyDef.angularDamping = 1.0;
    b2FixtureDef* fixtureDef=new b2FixtureDef();
    fixtureDef->density=3.0;
    fixtureDef->restitution=0.0;
    fixtureDef->friction=1.0;
    fixtureDef->filter.groupIndex=-1;
    b2Body* car_body = world->CreateBody(&bodyDef);

    // here i build the custom polygons to form complex body 
    polygonShape = new b2PolygonShape();
    b2Vec2 *vertices = new b2Vec2 [10 ];
    // setting the vertices all working great : 
    ...
    ...
    ...
    polygonShape->Set(vertices,10);
    fixtureDef->shape = polygonShape;
    car_body->CreateFixture(fd);



    // --------  trying to attach the axle to the main car buy 


    b2BodyDef axlecontainerBodyDef;
    axlecontainerBodyDef.userData = axlecontainerSprite;
    axlecontainerBodyDef.type=b2_dynamicBody;
    axlecontainerBodyDef.position.Set(((screenSize.width/2.0))/PTM_RATIO,(screenSize.height/2.0)/PTM_RATIO);
    b2Body* axlecontainerBody = world->CreateBody(&axlecontainerBodyDef);

    b2FixtureDef * axleContainerFixture = new b2FixtureDef();

    axleContainerFixture->density=1.0;       
    axleContainerFixture->friction=1.0;
    //axleContainerFixture->restitution=1.0;
    axleContainerFixture->isSensor = false;

    //LEFT AXLE CONTAINER 
    // here i build the custom polygons to form complex new body to be attached to the main car body
    polygonShape = new b2PolygonShape();
    b2Vec2 *vertices = new b2Vec2\[10\];
    // setting the vertices all working great : 
    ...
    ...
    ...
    polygonShape->Set(vertices,10);
    axleContainerFixture->shape = polygonShape;
    axlecontainerBody->CreateFixture(fd);


    b2WeldJointDef *weldJointDef = new b2WeldJointDef();



    weldJointDef->bodyA=body;
    weldJointDef->bodyB=axlecontainerBody;
    float x = axlecontainerBody->GetWorldCenter().x/PTM_RATIO;
    float y = axlecontainerBody->GetWorldCenter().y/PTM_RATIO;
    weldJointDef->Initialize(body,axlecontainerBody,body->GetWorldCenter());
    world->CreateJoint(weldJointDef);

enter image description here

Answer 1

您的代码的这一部分看起来有点可疑：

weldJointDef->localAnchorA.Set(-0.5, -0.3);
weldJointDef->localAnchorB.Set(-0.5, -0.3);

相对于两者焊接锚点的主体的局部空间位置似乎很奇怪（-0.5，-0.3）。这是对的吗？

上次我必须创建焊接接头时，我使用了关节的Initialize（...）函数这样做了。：

   void CreateIdleJoint()
   {
      // Create a weld joint between the
      // body and the thing it is moving on.
      b2WeldJointDef jointDef;
      jointDef.Initialize(_bodyMoving, _bodyMovingOn, _bodyMovingOn->GetWorldCenter());
      jointDef.dampingRatio = 0.5;
      jointDef.frequencyHz = 2.0;
      jointDef.collideConnected = true;
      _bodyMoving->GetWorld()->CreateJoint(&jointDef);
   }

作为参考，这是Initialize函数的内部结构：

void b2WeldJointDef::Initialize(b2Body* bA, b2Body* bB, const b2Vec2& anchor)
{
    bodyA = bA;
    bodyB = bB;
    localAnchorA = bodyA->GetLocalPoint(anchor);
    localAnchorB = bodyB->GetLocalPoint(anchor);
    referenceAngle = bodyB->GetAngle() - bodyA->GetAngle();
}

b2焊接接头Def不显示在自定义多边形之间

1 个答案: