Cocos 2D SetAsEdge 问题

Question

我正在尝试用 Cocos 2D 和 Cocos 制作一款游戏。 Box 2D

但当我尝试放置“setAsEdge”时，它只是说该函数不存在

我的代码：

// Define the ground body.
    b2BodyDef groundBodyDef;
    groundBodyDef.position.Set(0, 0); // bottom-left corner

    // Call the body factory which allocates memory for the ground body
    // from a pool and creates the ground box shape (also from a pool).
    // The body is also added to the world.
    groundBody = world->CreateBody(&groundBodyDef);

    // Define the ground box shape.
    b2PolygonShape groundBox;       

    // bottom
    groundBox.SetAsEdge(b2Vec2(0,FLOOR_HEIGTH/PTM_RATIO), b2Vec2(screenSize.width*2.0f/PTM_RATIO,FLOOR_HEIGTH/PTM_RATIO));
    groundBody->CreateFixture(&groundBox,0);

    // top
    groundBox.SetAsEdge(b2Vec2(0,screenSize.height/PTM_RATIO), b2Vec2(screenSize.width*2.0f/PTM_RATIO,screenSize.height/PTM_RATIO));
    groundBody->CreateFixture(&groundBox,0);

    // left
    groundBox.SetAsEdge(b2Vec2(0,screenSize.height/PTM_RATIO), b2Vec2(0,0));
    groundBody->CreateFixture(&groundBox,0);

    // right
    groundBox.SetAsEdge(b2Vec2(screenSize.width*2.0f/PTM_RATIO,screenSize.height/PTM_RATIO), b2Vec2(screenSize.width*2.0f/PTM_RATIO,0));
    groundBody->CreateFixture(&groundBox,0);

错误：“b2PolygonShape”中没有名为“SetAsEdge”的成员。我正在使用 Cocos 2D 1.0.1 稳定版

谢谢大家

Answer 1

您正在使用 Box2D 2.2.1，其 API 与 Cocos2D v1.0.1 中的 Box2D 版本相比发生了变化（使用 Box2D v2.1.2）。我想你使用的是Cocos2D 2.0 alpha？如果是这样，它应该附带更新的 Xcode 项目模板，因此您可能需要安装这些模板并基于新模板创建项目。

以下是我如何使用附加有 4 个形状的主体来设置边框边界框：

    // for the screenBorder body we'll need these values
    CGSize screenSize = [CCDirector sharedDirector].winSize;
    float widthInMeters = screenSize.width / PTM_RATIO;
    float heightInMeters = screenSize.height / PTM_RATIO;
    b2Vec2 lowerLeftCorner = b2Vec2(0, 0);
    b2Vec2 lowerRightCorner = b2Vec2(widthInMeters, 0);
    b2Vec2 upperLeftCorner = b2Vec2(0, heightInMeters);
    b2Vec2 upperRightCorner = b2Vec2(widthInMeters, heightInMeters);

    // Define the static container body, which will provide the collisions at screen borders.
    b2BodyDef screenBorderDef;
    screenBorderDef.position.Set(0, 0);
    b2Body* screenBorderBody = world->CreateBody(&screenBorderDef);
    b2EdgeShape screenBorderShape;

    // Create fixtures for the four borders (the border shape is re-used)
    screenBorderShape.Set(lowerLeftCorner, lowerRightCorner);
    screenBorderBody->CreateFixture(&screenBorderShape, 0);
    screenBorderShape.Set(lowerRightCorner, upperRightCorner);
    screenBorderBody->CreateFixture(&screenBorderShape, 0);
    screenBorderShape.Set(upperRightCorner, upperLeftCorner);
    screenBorderBody->CreateFixture(&screenBorderShape, 0);
    screenBorderShape.Set(upperLeftCorner, lowerLeftCorner);
    screenBorderBody->CreateFixture(&screenBorderShape, 0);

或者，获取 Kobold2D Preview 5 （明天可用）并查看Physics-Box2D 模板项目。我进行了运行 Box2D v2.2.1 应用程序所需的所有更改，包括 Box2D 调试绘图类所需的更改。我还托管最新的 Box2D API 参考。

Answer 2

使用 b2EdgeShape 代替 b2PolygonShape，例如：

b2EdgeShape groundBox;
groundBox.Set( b2Vec2(0,0), b2Vec2(winSize.width/PTM_RATIO,0));

Answer 3

使用

setAsBox(0,0,b2vec2(0,0),0);