cocos2d-iphone - 在 cocos2d 和花栗鼠中从 CGRect 创建一个 cpShape

Question

我不知道如何创建适合 CGRect 的 cpShape。到目前为止，这是我尝试过的，但没有成功：

    CGPoint p1 = rect.origin;
    CGPoint p2 = CGPointMake(rect.origin.x + rect.size.width, rect.origin.y);
    CGPoint p3 = CGPointMake(rect.origin.x, rect.origin.y + rect.size.height);
    CGPoint p4 = CGPointMake(rect.origin.x + rect.size.width, rect.origin.y + rect.size.height);

    int num = 4;
    CGPoint verts[] = {p2, p1, p3, p4};
    shape = cpPolyShapeNew(body, num, verts, cpvzero);

我不明白为什么这不完全适合我的 CGRect ？

Answer 1

代表用户251552回答

好的，我想通了：

//Converting points in chipmunk coordinates
    CGPoint p1 = CGPointMake(-rect.size.width/2, -rect.size.height/2);
    CGPoint p2 = CGPointMake(-rect.size.width/2, +rect.size.height/2);
    CGPoint p3 = CGPointMake(+rect.size.width/2, +rect.size.height/2);
    CGPoint p4 = CGPointMake(+rect.size.width/2, -rect.size.height/2);

    int num = 4;
    CGPoint verts[] = {p1, p2, p3, p4};

    shape = cpPolyShapeNew(body, num, verts, cpvzero);