在iOS2的box2d中，如何找到两个圆形体之间的距离？ [英] In box2d for iOS, how to find the distance between two circular bodies?

问题描述

我使用以下代码来获取两个不同半径的圆形体之间的距离：

I am using the following code to get the distance between two circular bodies of different radius:

distance = b2Distance(body1->GetPosition(), body2->GetPosition());

我已经意识到可变距离存储了两个身体中心之间的距离，但不是边界之间的距离。我想要的是当两个身体接触时距离= 0.

I have realized that variable distance is storing the distance between the two centers of the bodies, but not the distance between the borders. What I want is distance=0 when the two bodies are touching.

我该怎么做？我一直在尝试这个代码，但它失败了：

How can I do that? I've been trying this code but it fails:

b2DistanceInput *distanceInput;
distanceInput->transformA = body1->GetTransform();
distanceInput->transformB = body2->GetTransform();
b2DistanceProxy *proxyA;
proxyA->Set(fixtureBody1->GetShape(), 1);
b2DistanceProxy *proxyB;
proxyB->Set(fixtureBody2->GetShape(), 1);
distanceInput->proxyA = *proxyA;
distanceInput->proxyB = *proxyB;
b2DistanceOutput *theDistance;
b2SimplexCache *cache;
cache->count = 0;
b2Distance(theDistance, cache, distanceInput);

getShape方法在b2box代码中提供了错误的访问错误。

The getShape method is giving a bad access error within the b2box code.

任何想法？

谢谢，

GA

推荐答案

尝试使用此代码 - 它对我有用：

Try use this code - it work for me:

b2DistanceInput *distanceInput = new b2DistanceInput();
b2DistanceProxy *proxyA = new b2DistanceProxy();
b2DistanceProxy *proxyB = new b2DistanceProxy();
b2SimplexCache *cache = new b2SimplexCache();
b2DistanceOutput *theDistance = new b2DistanceOutput();

proxyA->Set(fixtureBody1->GetShape(),1);
proxyB->Set(fixtureBody2->GetShape(),1);

distanceInput->transformA = body1->GetTransform();
distanceInput->transformB = body2->GetTransform();
distanceInput->proxyA = *proxyA;
distanceInput->proxyB = *proxyB;
distanceInput->useRadii = true;

cache->count = 0;

b2Distance(theDistance, cache, distanceInput);

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