Cocos2d：如何检测旋转精灵的触摸？

Question

如何检测旋转的CCSprite上的触摸？

我熟悉使用ccTouchesBegan和contentSize、anchorPoint等通用技术，让精灵检测触摸是否在其范围内......但是，一旦精灵被旋转了一定角度，我就不知道该怎么做了。

我希望精灵本身能够检测触摸（封装），并通过委托将事件报告给另一个对象。

如果有人有代码可分享......那就太好了。

- poundev23

Answer 1

尝试使用CCNode convertTouchToNodeSpaceAR:方法将点转换为旋转坐标，然后您可以比较精灵边界。我将其作为CCNode类别，因此可用于任何CCNode或子类。

@interface CCNode (gndUtils)

// Lets a node test to see if a touch is in it.
// Takes into account the scaling/rotation/transforms of all 
// the parents in the parent chain.
// Note that rotation of a rectangle doesn't produce a rectangle 
// (and we are using a simple rectangle test)
//   so this is testing the smallest rectangle that encloses the rotated node.
// This does the converstion to view and then world coordinates
// so if you are testing lots of nodes, do that converstion manually
//
//  CGPoint touchLoc = [touch locationInView: [touch view]];  // convert to "View"
//  touchLoc = [[CCDirector sharedDirector] convertToGL: touchLoc]; // move to "World"
// and then use worldPointInNode: method instead for efficiency.

- (BOOL) touchInNode: (UITouch *) touch;

// allows a node to test if a world point is in it.
- (BOOL) worldPointInNode: (CGPoint) worldPoint;

@end

实现方式：

@implementation CCNode (gndUtils)

- (BOOL) touchInNode: (UITouch *) touch
{
    CGPoint touchLoc = [touch locationInView: [touch view]];            // convert to "View coordinates" from "window" presumably
    touchLoc = [[CCDirector sharedDirector] convertToGL: touchLoc];     // move to "cocos2d World coordinates"

    return [self worldPointInNode: touchLoc];
}

- (BOOL) worldPointInNode: (CGPoint) worldPoint
{
    // scale the bounding rect of the node to world coordinates so we can see if the worldPoint is in the node.
    CGRect bbox = CGRectMake( 0.0f, 0.0f, self.contentSize.width, self.contentSize.height );    // get bounding box in local 
    bbox = CGRectApplyAffineTransform(bbox, [self nodeToWorldTransform] );      // convert box to world coordinates, scaling etc.
    return CGRectContainsPoint( bbox, worldPoint );
}
@end

- Dad

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有没有办法在cocos2d 2上做到这一点？我遇到了一些错误。我认为自从这篇文章写出来以后，有些东西已经被弃用了。谢谢！ - Corey

可以运行。这应该内置于cocos2d中。 :-) - Pat McG

请查看 Sofi Software LLC 提供的备选建议，这可能更快且绝对更准确。已点赞。 - Dad

Answer 2

@Dad的代码将节点的bbox转换为世界坐标系。对于旋转的节点，这会扩展bbox，并可能返回在实际节点外但在世界bbox内的触摸事件。为避免这种情况，应将世界点转换为节点的坐标空间，并在那里测试本地点。

- Sofi Software LLC

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我相信我遇到了你在这里描述的问题，但我不理解你提出的解决方案。你能详细说明一下吗？ - mwright

Answer 3

正如 Absinthe 所说的那样 - poundev23 的代码只检查了旋转精灵周围的 BB。 我已经编写了正确的代码（但是在Cocos2dx-c++上）-希望对某人有所帮助:

CCSize size = this->getContentSize();
CCRect rect = CCRect(0, 0, size.width, size.height);
CCPoint pt = touch->locationInView();
pt = CCDirector::sharedDirector()->convertToGL(pt);
pt = CCPointApplyAffineTransform(pt, this->worldToNodeTransform());
bool b = CCRect::CCRectContainsPoint(rect, pt);

祝你编写愉快！

编辑： 好的解决方案！我将其转换为Objective C。

- (BOOL) containsTouchLocation:(UITouch *) touch
{
    CGSize size = self.contentSize;
    CGRect rect = CGRectMake(0, 0, size.width, size.height);
    CGPoint touchLocation = [touch locationInView: [touch view]];
    touchLocation = [[CCDirector sharedDirector] convertToGL:touchLocation];
    touchLocation = CGPointApplyAffineTransform(touchLocation, self.worldToNodeTransform);
    bool containsPoint = CGRectContainsPoint(rect, touchLocation);

    return containsPoint;
}

- Sergey Kopanev

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转换为Obj-C并将其作为编辑添加。谢谢，它运行良好。 - some_id