ios - 真的需要 SKSpriteNode child 才能正确拍摄
<p><p>所以我有一个 shipNode(最初朝右)，有两个名为 _laserCannon1(和 2)的子节点，它们通过以下方法配置:</p>
<pre><code>-(void)initializeLaserCannonLocations
{
CGSize size = CGSizeMake(4.0, 4.0);
_laserCannon1 = size:size];
_laserCannon2 = size:size];
_laserCannon1.position = CGPointMake(self.size.width/2, self.size.height/2 + 15);
_laserCannon2.position = CGPointMake(self.size.width/2, self.size.height/2 - 15);
;
;
}
</code></pre>
<p>然后我稍后会根据飞船的 zRotation 从他们身上“发射”激光，如下所示</p>
<pre><code>-(void)fireLocalLaser
{
CGVector standardLaserVelocity = CGVectorMake(700*cosf(_myShip.zRotation - _myShip.laserCannon1.zRotation),
700*sinf(_myShip.zRotation - _myShip.laserCannon2.zRotation));
;
;
}
</code></pre>
<p>现在，当船只直接面向左侧或右侧时，一切正常，但由于某些奇怪的原因，随着船只开始更多地面向顶部或底部，炮弹越来越多地朝船中部射击，以至于一旦船垂直面对，两枪都是从船的 middle.position.x 发射的。这与我放置 _laserCannons 的位置有关吗？</p></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>我希望我的数学老师没有看到这个!</p>
<p>您的问题在于 2 个激光炮在旋转时的相对位置。我已经附上了一张图片，所以我不必对正在发生的事情进行冗长的描述。</p>
<p> <img src="/image/ekQcJ.png" alt="enter image description here"/> </p>
<p>我已经包含了一个有点，有点，管道胶带解决方案的代码，如果你真的想要，你可以如何做到这一点。它不漂亮，但它有效。代码在 0 到 90 度范围内都很好，所以如果你下定决心要拥有 2 门大炮，你应该能够从那里解决剩下的问题。但我强烈建议您的 Mighty Space Empire 投资于单炮舰，因为这将使您的编码工作变得更加轻松!</p>
<pre><code>@implementation MyScene {
SKSpriteNode *ship1;
SKShapeNode *turret1;
SKShapeNode *turret2;
}
-(id)initWithSize:(CGSize)size
{
if (self = ) {
self.physicsWorld.contactDelegate = self;
;
}
return self;
}
-(void)createSpaceships {
ship1 = size:CGSizeMake(50, 50)];
ship1.position = CGPointMake(300, 150);
ship1.physicsBody = ;
ship1.physicsBody.dynamic = NO;
;
SKSpriteNode *frontOfShip = size:CGSizeMake(2, 50)];
frontOfShip.position = CGPointMake(25, 0);
;
}
-(void)update:(CFTimeInterval)currentTime {
/* Called before each frame is rendered */
}
// touch the left side of the screen to rotate the ship by +0.0785398 radians
// touch the right hand side of the screen to fire lasers
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = ;
CGPoint touchLocation = ;
if(touchLocation.x < self.size.width/2) // left side of screen
{
SKAction *block0 = [SKAction runBlock:^{
ship1.zRotation = ship1.zRotation +0.0785398;
}];
;
} else // right side of screen
{
float turret1offsetX = 0;
float turret1offsetY = 0;
float turret2offsetX = 0;
float turret2offsetY = 0;
if((ship1.zRotation >0) && (ship1.zRotation <=0.785399))
{
turret1offsetX = (14/0.785398) * ship1.zRotation;
turret1offsetY = (23/0.785398) * ship1.zRotation;
turret2offsetX = (-20/0.785398) * ship1.zRotation;
turret2offsetY = (10/0.785398) * ship1.zRotation;
}
if((ship1.zRotation >0.785399) && (ship1.zRotation <=1.570797))
{
turret1offsetX = (14 - (9/0.785398)) * ship1.zRotation;
turret1offsetY = -4 + (27/0.785398) * ship1.zRotation;
turret2offsetX = (3 - (25/0.785398)) * ship1.zRotation;
turret2offsetY = 20 - (10/0.785398) * ship1.zRotation;
}
int x = ship1.position.x + 1000 * cos(ship1.zRotation);
int y = ship1.position.y + 1000 * sin(ship1.zRotation);
turret1 = ;
CGMutablePathRef pathToDraw = CGPathCreateMutable();
CGPathMoveToPoint(pathToDraw, NULL, (ship1.position.x+20)+turret1offsetX, (ship1.position.y-25)+turret1offsetY);
CGPathAddLineToPoint(pathToDraw, NULL, x, y);
turret1.path = pathToDraw;
];
;
turret2 = ;
CGMutablePathRef pathToDraw2 = CGPathCreateMutable();
CGPathMoveToPoint(pathToDraw2, NULL, (ship1.position.x+20)+turret2offsetX, (ship1.position.y+25)+turret2offsetY);
CGPathAddLineToPoint(pathToDraw2, NULL, x, y);
turret2.path = pathToDraw2;
];
;
}
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
;
;
}
@end
</code></pre></p>
<p style="font-size: 20px;">关于ios - 真的需要 SKSpriteNodechild 才能正确拍摄，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/22966579/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/22966579/
</a>
</p>
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