我在使用SpriteKit的Swift 3时遇到了关于接触检测的问题。接触检测有时可以正常工作,但有时则不能。这似乎是完全随机的。
我有一个黄色的“子弹”,它向上移动以击中名为targetSprite的红色精灵。期望的行为是当子弹击中目标时将其移除,但有时它只是从下面穿过。
我发现很多关于接触检测根本无法工作的问题,但我没有找到任何处理不一致检测的内容。
我该怎么办才能解决这个问题?
以下是代码:
我有一个黄色的“子弹”,它向上移动以击中名为targetSprite的红色精灵。期望的行为是当子弹击中目标时将其移除,但有时它只是从下面穿过。
我发现很多关于接触检测根本无法工作的问题,但我没有找到任何处理不一致检测的内容。
我该怎么办才能解决这个问题?
以下是代码:
import SpriteKit
import GameplayKit
enum PhysicsCategory:UInt32 {
case bullet = 1
case sprite1 = 2
case targetSprite = 4
// each new value should double the previous
}
class GameScene: SKScene, SKPhysicsContactDelegate {
// Create sprites
let sprite1 = SKSpriteNode(color: SKColor.blue, size: CGSize(width:100,height:100))
let targetSprite = SKSpriteNode(color: SKColor.red, size: CGSize(width:100,height:100))
let bullet = SKSpriteNode(color: SKColor.yellow, size: CGSize(width: 20, height: 20))
// show the bullet?
var isShowingBullet = true
// Timers
//var timer:Timer? = nil
var fireBulletTimer:Timer? = nil
// set up bullet removal:
var bulletShouldBeRemoved = false
let bulletMask = PhysicsCategory.bullet.rawValue
override func didMove(to view: SKView) {
// Physics
targetSprite.physicsBody = SKPhysicsBody(rectangleOf: targetSprite.centerRect.size)
targetSprite.physicsBody?.affectedByGravity = false
bullet.physicsBody = SKPhysicsBody(rectangleOf: bullet.centerRect.size)
bullet.physicsBody?.affectedByGravity = false
// Contact Detection:
targetSprite.physicsBody?.categoryBitMask = PhysicsCategory.targetSprite.rawValue
targetSprite.physicsBody?.contactTestBitMask =
//PhysicsCategory.sprite1.rawValue |
PhysicsCategory.bullet.rawValue
targetSprite.physicsBody?.collisionBitMask = 0 // no collision detection
// bullet physics
bullet.physicsBody?.categoryBitMask = PhysicsCategory.bullet.rawValue
bullet.physicsBody?.contactTestBitMask =
PhysicsCategory.targetSprite.rawValue
bullet.physicsBody?.collisionBitMask = 0 // no collision detection
// execute once:
fireBulletTimer = Timer.scheduledTimer(timeInterval: 1,
target: self,
selector: #selector(self.fireBullet),
userInfo: nil,
repeats: false)
// Add sprites to the scene:
self.addChild(sprite1)
self.addChild(bullet)
self.addChild(targetSprite)
// Positioning
targetSprite.position = CGPoint(x:0, y:300)
// Note: bullet and sprite1 are at 0,0 by default
// Delegate
self.physicsWorld.contactDelegate = self
}
func didBegin(_ contact: SKPhysicsContact) {
print("didBegin(contact:))")
//let firstBody:SKPhysicsBody
// let otherBody:SKPhysicsBody
// Use 'bitwise and' to see if both bits are 1:
if contact.bodyA.categoryBitMask & bulletMask > 0 {
//firstBody = contact.bodyA
//otherBody = contact.bodyB
print("if contact.bodyA....")
bulletShouldBeRemoved = true
}
else {
//firstBody = contact.bodyB
//otherBody = contact.bodyA
print("else - if not contacted?")
}
/*
// Find the type of contact:
switch otherBody.categoryBitMask {
case PhysicsCategory.targetSprite.rawValue: print(" targetSprite hit")
case PhysicsCategory.sprite1.rawValue: print(" sprite1 hit")
case PhysicsCategory.bullet.rawValue: print(" bullet hit")
default: print(" Contact with no game logic")
}
*/
} // end didBegin()
func didEnd(_ contact: SKPhysicsContact) {
print("didEnd()")
}
func fireBullet() {
let fireBulletAction = SKAction.move(to: CGPoint(x:0,y:500), duration: 1)
bullet.run(fireBulletAction)
}
func showBullet() {
// Toggle to display or not, every 1 second:
if isShowingBullet == true {
// remove (hide) it:
bullet.removeFromParent()
// set up the toggle for the next call:
isShowingBullet = false
// debug:
print("if")
}
else {
// show it again:
self.addChild(bullet)
// set up the toggle for the next call:
isShowingBullet = true
// debug:
print("else")
}
}
override func update(_ currentTime: TimeInterval) {
// Called before each frame is rendered
if bulletShouldBeRemoved {
bullet.removeFromParent()
}
}
}
抱歉缩进不一致,我似乎找不到简单的方法来解决这个问题...
编辑:
我发现使用“frame”而不是“centerRect”可以使碰撞区域与精灵大小相同。例如:
targetSprite.physicsBody = SKPhysicsBody(rectangleOf: targetSprite.centerRect.size)
should be:
targetSprite.physicsBody = SKPhysicsBody(rectangleOf: targetSprite.frame.size)