cocos2d flappy bird演示

Question

我正在使用flappy bird演示，尝试不同的东西，只是为了“了解彼此”。通过演示，我已经成功地将游戏的方向更改为垂直向上滚动。将CGFloat反转为负值会使我的障碍向上移动，但一旦它们超出界限，它们就不会重新产生。如果我更改向下滚动的值，它们将根据update方法重新生成。有人能解释一下我在x到y的转换中做错了什么吗？为什么屏幕的底部可以识别，而屏幕的顶部不能识别？提前感谢

#import "MainScene.h"

static const CGFloat scrollSpeed = -280.f; //upwards
static const CGFloat firstObstaclePosition = -568.f; 
static const CGFloat distanceBetweenObstacles = 80;

@implementation MainScene {
CCSprite *_hero;
CCPhysicsNode *_physicsNode;
NSMutableArray *_obstacles;
}

- (void)spawnNewObstacle {
CCNode *previousObstacle = [_obstacles lastObject];
CGFloat previousObstacleYPosition = previousObstacle.position.y;
if (!previousObstacle) {
    // this is the first obstacle
    previousObstacleYPosition = firstObstaclePosition;
}
CCNode *obstacle = [CCBReader load:@"Obstacle"];
obstacle.position = ccp(0, previousObstacleYPosition + distanceBetweenObstacles);
[_physicsNode addChild:obstacle];
[_obstacles addObject:obstacle];
}
- (void)update:(CCTime)delta {
_hero.position = ccp(_hero.position.x, _hero.position.y + delta * scrollSpeed);//move on Y axis
_physicsNode.position = ccp(_physicsNode.position.x, _physicsNode.position.y - (scrollSpeed *delta));//scroll in Y axis
//spawn more
NSMutableArray *offScreenObstacles = nil;
for (CCNode *obstacle in _obstacles) {
    CGPoint obstacleWorldPosition = [_physicsNode convertToWorldSpace:obstacle.position];
    CGPoint obstacleScreenPosition = [self convertToNodeSpace:obstacleWorldPosition];
    if (obstacleScreenPosition.y < -obstacle.contentSize.height) {
        if (!offScreenObstacles) {
            offScreenObstacles = [NSMutableArray array];
        }
        [offScreenObstacles addObject:obstacle];
    }
}
for (CCNode *obstacleToRemove in offScreenObstacles) {
    [obstacleToRemove removeFromParent];
    [_obstacles removeObject:obstacleToRemove];
    // for each removed obstacle, add a new one
    [self spawnNewObstacle];
}
}

- (void)didLoadFromCCB {
self.userInteractionEnabled = TRUE;
_obstacles = [NSMutableArray array];
[self spawnNewObstacle];
[self spawnNewObstacle];
[self spawnNewObstacle];
}

- (void)touchBegan:(UITouch *)touch withEvent:(UIEvent *)event {

}
@end

我附上了来自某人的_physicsNode截图。

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Answer 1

看起来，如果你的障碍物是一个短的、恒定的高度，并且它们之间的距离足够大，那么你的障碍物就会产生良好的效果。合并障碍物的高度可能会更好，以获得更有意义的距离变量值。这只是个想法。

这行字-

obstacle.position = ccp(0, previousObstacleYPosition + distanceBetweenObstacles);

可能是-

obstacle.position = ccp(0, previousObstacleYPosition + distanceBetweenObstacles + previousObstacle.contentSize.height);

至于垂直滚动向下而不是向上滚动的问题，我相信是因为下面这行：

if (obstacleScreenPosition.y < -obstacle.contentSize.height) {

由于这条线负责确定一个障碍物何时离开屏幕，因此它会影响下一个障碍物的产生。这就是为什么这一行适用于向下滚动，但需要更改为向上滚动的原因。

尝试：

 if (obstacleScreenPosition.y > (_physicsNode.contentSize.height + obstacle.contentSize.height)) {

您可能需要也可能不需要障碍物的大小，具体取决于障碍物的锚定位置。

我希望这行得通，祝你好运。