Ios `-costToNode:`未发送到GameplayKit中的GKGraphNode2D子类

我有一个关于苹果新游戏工具包的愚蠢问题

我正在为我的游戏创建一个基于二维网格的节点布局。我最喜欢

GKGraphNode2D

的功能，但我想用一种方式对其进行调整。我想在遍历某种节点对时有条件地增加一个惩罚。换句话说，我希望一些节点以一种直接的方式连接，而一些节点的连接使得我的应用程序可以修改它们的遍历距离

我认为子类化

GKGraphNode2D

并重写

-costToNode:

和

-estimatedCostToNode:

将非常有效！有时我会返回

super

提供的值，然后在其他时候为我的游戏调整它。这两种方法是

gkgraphnode2d

的超类

GKGraphNode

上的方法

不幸的是，当我尝试这样做时，似乎从未在我的

GKGraphNode2D

子类中调用

-costToNode:

和

-estimatedCostToNode:

。我希望在调用

GKGraph

对象上的

-findPathFromNode:toNode:

时调用这些方法，该对象包含一组

GKGraphNode2D

子类对象

我做错了什么

编辑： 下面是我的代码

创建两个类，

CheapNode

和

ExpensiveNode

，它们是

GKGraphNode2D

的子类，如下所示：

@import UIKit;
@import GameplayKit;

@interface CheapNode : GKGraphNode2D
@end

@implementation CheapNode

- (float)estimatedCostToNode:(GKGraphNode *)node {
    return 1;
}

- (float)costToNode:(GKGraphNode *)node {
    return 1;
}

@end

及

然后在一个测试中，我创建了一些节点，将它们连接起来，将它们添加到一个图中，并将

findPathFromNode:toNode:

消息发送到该图中。然后，我检查了图形找到的路径，但没有找到我所期望的

- (void)testNodeCostsUsed {
    /*
     This is the graph we are creating:

     A---B---C
     |       |
     F---E---D

     where all of the nodes are `CheapNode` objects, except 'B', which is an
     `ExpensiveNode` object.

     This test finds a path from node A to node C.

     If the cost methods in the `CheapNode` and `ExpensiveNode` subclasses
     are used, the route going from A to C around B (down, then right, then up)
     should be used, since the cost of going from B to C is 100, and the cost of
     going from any other node to any other node is 1 
     (see implementation of these classes).

     Instead, we see `GKGraph` choosing the "shortest" route in terms of number
     of nodes, from the top left immediately to the right to the top right.
     */

    CheapNode     *nodeA = [[CheapNode alloc]     initWithPoint:(vector_float2){0, 0}];
    ExpensiveNode *nodeB = [[ExpensiveNode alloc] initWithPoint:(vector_float2){1, 0}];
    CheapNode     *nodeC = [[CheapNode alloc]     initWithPoint:(vector_float2){2, 0}];
    CheapNode     *nodeD = [[CheapNode alloc]     initWithPoint:(vector_float2){2, 1}];
    CheapNode     *nodeE = [[CheapNode alloc]     initWithPoint:(vector_float2){1, 1}];
    CheapNode     *nodeF = [[CheapNode alloc]     initWithPoint:(vector_float2){0, 1}];

    [nodeA addConnectionsToNodes:@[ nodeB, nodeF ] bidirectional:YES];
    [nodeC addConnectionsToNodes:@[ nodeB, nodeD ] bidirectional:YES];
    [nodeE addConnectionsToNodes:@[ nodeF, nodeD ] bidirectional:YES];

    NSArray *allNodes = @[ nodeA, nodeB, nodeC, nodeD, nodeE, nodeF ];

    GKGraph *graph = [GKGraph graphWithNodes:allNodes];
    NSArray *nodes = [graph findPathFromNode:nodeA toNode:nodeC];

    NSArray *expectedPath   = @[ nodeA, nodeF, nodeE, nodeD, nodeC ];
    NSArray *prohibitedPath = @[ nodeA, nodeB, nodeC ];

    XCTAssert([nodes isEqualToArray:expectedPath], @"");
    XCTAssertFalse([nodes isEqualToArray:prohibitedPath], @"");
}

此测试用例失败。我还注意到，

estimatedCostToNode:

和

costToNode:

从未发送到我的

GKGraphNode2D

子类（通过日志语句和断点验证）

是演示此问题的示例项目。它应该在最新的开发者测试版Xcode上构建和运行（截至2015年8月31日，Xcode测试版6）

编辑2： 如果有人对复制感兴趣，我已经将StackOverflow问题中的示例代码和描述作为bug（）提交。如果在iOS 9发布后bug仍然存在，我将使用开发人员支持票证来尝试解决此问题

编辑3：

---

苹果在我的开发者支持票上回复了我。他们承认这是一个bug，而且它（据我所知）似乎在iOS9.2Beta2（7C46t）中得到了修复 苹果回复了我关于这个问题的开发者支持票，并告诉我这是一个已知的问题，并且在2015年11月3日发布的iOS SDK 9.2 beta 2中有一个潜在的修复程序。我验证了我在9.2b2中通过的测试，因此我希望该版本能够解决此问题。

好吧，您明显做错的一件事是没有发布代码，以便有人可以检查代码是否存在任何（或多或少明显的）问题。；）我只能告诉你，这是正确的方法，它对我来说是有效的（网格图）。我有一个类似的问题，我在这里问过：包括我现在的代码using@LearnCocos2D示例代码发布！你有更新吗？我对此也很感兴趣。@Weston检查问题的最新编辑，这个错误应该在9.2 beta 2I测试中修复，这一点得到了确认

- (void)testNodeCostsUsed {
    /*
     This is the graph we are creating:

     A---B---C
     |       |
     F---E---D

     where all of the nodes are `CheapNode` objects, except 'B', which is an
     `ExpensiveNode` object.

     This test finds a path from node A to node C.

     If the cost methods in the `CheapNode` and `ExpensiveNode` subclasses
     are used, the route going from A to C around B (down, then right, then up)
     should be used, since the cost of going from B to C is 100, and the cost of
     going from any other node to any other node is 1 
     (see implementation of these classes).

     Instead, we see `GKGraph` choosing the "shortest" route in terms of number
     of nodes, from the top left immediately to the right to the top right.
     */

    CheapNode     *nodeA = [[CheapNode alloc]     initWithPoint:(vector_float2){0, 0}];
    ExpensiveNode *nodeB = [[ExpensiveNode alloc] initWithPoint:(vector_float2){1, 0}];
    CheapNode     *nodeC = [[CheapNode alloc]     initWithPoint:(vector_float2){2, 0}];
    CheapNode     *nodeD = [[CheapNode alloc]     initWithPoint:(vector_float2){2, 1}];
    CheapNode     *nodeE = [[CheapNode alloc]     initWithPoint:(vector_float2){1, 1}];
    CheapNode     *nodeF = [[CheapNode alloc]     initWithPoint:(vector_float2){0, 1}];

    [nodeA addConnectionsToNodes:@[ nodeB, nodeF ] bidirectional:YES];
    [nodeC addConnectionsToNodes:@[ nodeB, nodeD ] bidirectional:YES];
    [nodeE addConnectionsToNodes:@[ nodeF, nodeD ] bidirectional:YES];

    NSArray *allNodes = @[ nodeA, nodeB, nodeC, nodeD, nodeE, nodeF ];

    GKGraph *graph = [GKGraph graphWithNodes:allNodes];
    NSArray *nodes = [graph findPathFromNode:nodeA toNode:nodeC];

    NSArray *expectedPath   = @[ nodeA, nodeF, nodeE, nodeD, nodeC ];
    NSArray *prohibitedPath = @[ nodeA, nodeB, nodeC ];

    XCTAssert([nodes isEqualToArray:expectedPath], @"");
    XCTAssertFalse([nodes isEqualToArray:prohibitedPath], @"");
}