I'm working in a game for my college and i stuck in one thing.
when i try to shoot with my hero the bullet go's up only or side i need my bullet go's where ever my hero rotate plz help me this is my code
func spownBullet() {
let bullet = SKSpriteNode(imageNamed: "Bullet")
let hero = self.childNodeWithName("hero") as! SKSpriteNode
bullet.zPosition = 1
bullet.position = CGPointMake(hero.position.x, hero.position.y)
bullet.size = CGSize(width: 20, height: 30)
let bulletact = SKAction.moveToY(self.size.height + 300, duration: 1)
bullet.runAction(SKAction.repeatActionForever(bulletact))
self.addChild(bullet)
}
If I understand correctly you want your bullet to go a certain distance (e.g. 300) in the same angle as your "hero" sprite is rotated.
Here's a function to compute the destination point:
// destination point moving at angle
// ---------------------------------
func endPointMovingSpriteFrom(origin:CGPoint, atAngle angle:CGFloat,forDistance distance:CGFloat ) -> CGPoint
{
let deltaX = distance / sin(angle + CGFloat(M_PI)/2)
let deltaY = distance / cos(angle + CGFloat(M_PI)/2)
return CGPoint(x: origin.x - deltaX, y:origin.y - deltaY)
}
You can use it to compute the destination and then use the destination in a moveTo action:
let bulletDestination = endPointMovingSpriteFrom(hero.position, atAngle:hero.zRotation, forDistance:300)
let bulletact = SKAction.moveTo(bulletDestination, duration: 1)
Related
I am trying to create a small game where SpriteNode (aka Player) moves up vertically on constant speed. I want to use its angle for steering left or right. However, I am not able to move the Player properly using its angle.
Thank you for your time.
Here is the partial code I wrote:
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if let touch = touches.first {
let location = touch.previousLocation(in: self)
if location.x < self.size.width / 2 && location.y < self.size.height / 2 {
// Turn Left
print("TURNING LEFT")
turn(left: true)
} else if location.x >= self.size.width / 2 && location.y < self.size.height / 2 {
// Turn Right
print("TURNING RIGHT")
turn(left: false)
} else if location.y > self.size.height / 2 {
// Go Up
print("GOING UP!")
move()
}
}
}
func turn(left: Bool) {
if left {
// Turn Left
let turnAction = SKAction.rotate(byAngle: 0.1, duration: 0.05)
let repeatAction = SKAction.repeatForever(turnAction)
player?.run(repeatAction)
} else {
// Turn Right
let turnAction = SKAction.rotate(byAngle: -0.1, duration: 0.05)
let repeatAction = SKAction.repeatForever(turnAction)
player?.run(repeatAction)
}
}
func move() {
// Move Up
let moveAction = SKAction.moveBy(x: 0, y: 15, duration: 0.5)
let repeatAction = SKAction.repeatForever(moveAction)
player?.run(repeatAction)
}
Using Trigonometry you can determine the sprite's x and y speed in either direction create an angle for the sprite to point towards. A great article that sums up how to do this can be found here.
If you simply wish to literally rotate the sprite it can be done by creating an SKAction for the rotation and running the action on the node.
// Create an action, duration can be changed from 0 so the user can see a smooth transition otherwise change will be instant.
SKAction *rotation = [SKAction rotateByAngle: M_PI/4.0 duration:0];
//Simply run the action.
[myNode runAction: rotation];
Thanks to #makertech81 link, I was able to write below code which works:
func move() {
// Move Up
let playerXPos = sin((player?.zRotation)!) * -playerSpeed
let moveAction = SKAction.moveBy(x: playerXPos, y: playerSpeed, duration: 0.5)
let repeatAction = SKAction.repeatForever(moveAction)
player?.run(repeatAction)
}
Basically, because I know the angle through zRotation and also I know how much Player will move toward Y, I was able to calculate its sin (which is X value). Therefore, moveAction will be properly calculated toward its destination.
Hope it helps.
I am trying to get my sprite to move and rotate to the location of my touch and follow as I move my finger around the screen. The movement part is working fine but I can't seem to get it to rotate. My moveAndRotate function is below.
func moveAndRotate(spriteNode: SKSpriteNode, toPosition position: CGPoint) {
let angle = atan2(position.y - player.position.y, position.x - player.position.x)
let rotateAction = SKAction.rotate(toAngle: angle - -(CGFloat(Double.pi / 2)), duration: 0.05, shortestUnitArc: true)
player.run(rotateAction)
let offsetX = position.x - player.position.x
let offsetY = position.y - player.position.y
let normal = simd_normalize(simd_double2(x: Double(offsetX), y: Double(offsetY)))
velocity = CGVector(dx: CGFloat(normal.x) * movePointsPerSecond, dy: CGFloat(normal.y) * movePointsPerSecond)
}
The duration was set to o.5 on the rotateAction, change it to 0 and it works fine.
I'm making a SpriteKit game. I have six cannons that I've made rotate back and fourth. I want to shoot cannonballs from each cannon that sync with the rotation of each cannon. I want a duration of one second between each cannonball.
So basically: A cannon that is in constant rotation is shooting cannonballs in the same direction as the rotation.
For the cannons i'm using an extension:
extension CGFloat {
func degreesToRadians() -> CGFloat {
return self * CGFloat.pi / 180
}
}
I'm gonna put the code for just one cannon, since I should be able to figure out how to adjust one of the cannonball movements to the others. Here is one:
func createCannons() {
let cannonLeftBottom = SKSpriteNode(imageNamed: "Cannon")
cannonLeftBottom.anchorPoint = CGPoint(x: 0.5, y: 0.5)
cannonLeftBottom.position = CGPoint(x: -325, y: -420)
cannonLeftBottom.zPosition = 4
cannonLeftBottom.setScale(0.4)
cannonLeftBottom.zRotation = CGFloat(65).degreesToRadians()
let rotateLB = SKAction.rotate(byAngle:
CGFloat(-65).degreesToRadians(), duration: 2)
let rotateBackLB = SKAction.rotate(byAngle:
CGFloat(65).degreesToRadians(), duration: 2)
let repeatRotationLB =
SKAction.repeatForever(SKAction.sequence([rotateLB,rotateBackLB]))
cannonLeftBottom.run(repeatRotationLB)
self.addChild(cannonLeftBottom)
}
Here is my function for the cannonball:
func createBalls() {
let cannonBallLB = SKSpriteNode(imageNamed: "Ball")
cannonBallLB.name = "CannonBall"
cannonBallLB.position = CGPoint(x: -325, y: -420)
cannonBallLB.physicsBody = SKPhysicsBody(circleOfRadius:
cannonBallLB.size.height / 2)
cannonBallLB.physicsBody?.affectedByGravity = false
cannonBallLB.zPosition = 3
cannonBallLB.setScale(0.1)
self.addChild(cannonBallLB)
}
THX!
You need to convert from Polar Coordinates to Rectangular Coordinates.
You do this by using sin and cos
E.G.
let speed = 100 //This would mean move 100 points per second
let force = CGVector(dx:cos(cannon.zRotation) * speed,dy:sin(cannon.zRotation) * speed)
cannonBall.applyForce(force)
Note: Now unless they changed this, force used to be in units of points, if they fixed it to units of meters, then you need to divide your speed by 150, since 150 points = 1 meter in Spritekit
I try to build 2D - top down game, and I have player (SKSpriteNode) he can move and rotate, and I want to shoot two bullets from him.
I use this code to shoot:
func setBullet(player: Player, bullet: Int)
{
let weaponPosition = scene!.convertPoint(player.weapon.position, fromNode: player)
var xPos, yPos: CGFloat!
let sinus = sin(player.zRotation)
let cosinus = cos(player.zRotation)
if bullet == 1
{
xPos = converted.x - sinus * player.size.height / 2
yPos = converted.y + cosinus * player.size.height / 2
}
else if bullet == 2
{
xPos = weaponPosition.x - sinus * player.size.height / 2
yPos = weaponPosition.y + cosinus * player.size.height / 2
}
position = CGPoint(x: xPos, y: yPos)
physicsBody!.applyImpulse(CGVector(dx: -sinus * normalSpeed, dy: cosinus * normalSpeed))
}
But, i do not know how to correctly set the position...
I try to make something like this
(Green dots - this is a bullets). Can anyone help me please!
Shooting multiple bullets in the same direction is fairly straightforward. The key is to determine the bullets' initial positions and direction vectors when the character is rotated.
You can calculate a bullet's initial position within the scene by
let point = node.convertPoint(weapon.position, toNode: self)
where node is the character, weapon.position is non-rotated position of a gun, and self is the scene.
Typically, a bullet moves to the right, CGVector(dx:1, dy:0), or up, CGVector (dx:0, dy:1), when the character is not rotated. You can calculate the direction of the impulse to apply to the bullet's physics body by rotating the vector by the character's zRotation with
func rotate(vector:CGVector, angle:CGFloat) -> CGVector {
let rotatedX = vector.dx * cos(angle) - vector.dy * sin(angle)
let rotatedY = vector.dx * sin(angle) + vector.dy * cos(angle)
return CGVector(dx: rotatedX, dy: rotatedY)
}
Here's an example of how to shoot two bullets from a rotated character:
struct Weapon {
var position:CGPoint
}
class GameScene: SKScene {
let sprite = SKSpriteNode(imageNamed:"Spaceship")
let dualGuns = [Weapon(position: CGPoint(x: -15, y: 15)), Weapon(position: CGPoint(x: 15, y: 15))]
let singleGun = [Weapon(position: CGPoint(x: 0, y: 15))]
let numGuns = 1
// If your character faces up where zRotation == 0, offset by pi
let rotationOffset = CGFloat(M_PI_2)
override func didMoveToView(view: SKView) {
scaleMode = .ResizeFill
sprite.position = view.center
sprite.size = CGSizeMake(25, 25)
self.addChild(sprite)
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
if let _ = touches.first {
let action = SKAction.rotateByAngle(CGFloat(M_PI_4/2), duration:1)
sprite.runAction(action) {
[weak self] in
if let scene = self {
switch (scene.numGuns) {
case 1:
for weapon in scene.singleGun {
scene.shoot(weapon: weapon, from: scene.sprite)
}
case 2:
for weapon in scene.dualGuns {
scene.shoot(weapon: weapon, from: scene.sprite)
}
default:
break
}
}
}
}
}
func shoot(weapon weapon:Weapon, from node:SKNode) {
// Convert the position from the character's coordinate system to scene coodinates
let converted = node.convertPoint(weapon.position, toNode: self)
// Determine the direction of the bullet based on the character's rotation
let vector = rotate(CGVector(dx: 0.25, dy: 0), angle:node.zRotation+rotationOffset)
// Create a bullet with a physics body
let bullet = SKSpriteNode(color: SKColor.blueColor(), size: CGSizeMake(4,4))
bullet.physicsBody = SKPhysicsBody(circleOfRadius: 2)
bullet.physicsBody?.affectedByGravity = false
bullet.position = CGPointMake(converted.x, converted.y)
addChild(bullet)
bullet.physicsBody?.applyImpulse(vector)
}
// Rotates a point (or vector) about the z-axis
func rotate(vector:CGVector, angle:CGFloat) -> CGVector {
let rotatedX = vector.dx * cos(angle) - vector.dy * sin(angle)
let rotatedY = vector.dx * sin(angle) + vector.dy * cos(angle)
return CGVector(dx: rotatedX, dy: rotatedY)
}
}
Suppose your player is a circle maked with SKShapeNode or SKSpriteNode.
Both of them have the frame property:
let f = player.frame
So, the first bullet can be in this position:
let firstBullet.position = CGPointMake(player.position.x-(f.width/2),player.position.y)
let secondBullet.position = CGPointMake(player.position.x+(f.width/2),player.position.y)
To know it during rotation do:
let firstBulletXPos = firstBullet.position.x - sinus * bullet.size.height / 2
let firstBulletYPos = firstBullet.position.y + cosinus * bullet.size.height / 2
let secondBulletXPos = secondBullet.position.x - sinus * bullet.size.height / 2
let secondBulletYPos = secondBullet.position.y + cosinus * bullet.size.height / 2
Is there a way to give an SKNode its own physics? I have an SKShapeNode call "backGround" which I use for the parent node of most of my other nodes. I am constantly moving "background" to the left, to give the illusion that the player is moving forward. However, one of the objects that has "backGround" as a parent node is a pin with a rope hanging from it. When background accelerates to the left, is there a way to make it so the rope doesn't swing back and forth, as ropes tend to do when accelerating or decelerating?
EDIT: Here is my code:
func createRopeNode(pos: CGPoint) -> SKSpriteNode{
let ropeNode = SKSpriteNode(imageNamed: "Ball")
ropeNode.size = CGSize(width: 5, height: 5)
ropeNode.physicsBody = SKPhysicsBody(rectangleOfSize: ropeNode.size)
ropeNode.physicsBody?.affectedByGravity = true
ropeNode.physicsBody?.collisionBitMask = 0
ropeNode.alpha = 1
ropeNode.position = CGPoint(x: pos.x + 0, y: pos.y)
ropeNode.name = "RopePiece"
let text = SKSpriteNode(imageNamed: "RopeTexture")
ropeNode.zPosition = -5
text.runAction(SKAction.rotateByAngle(atan2(-dx!, dy!), duration: 0))
ropeNode.addChild(text)
return ropeNode
}
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
/* Called when a touch begins */
if (!playerIsConnected){
playerIsConnected = true
for touch in (touches as! Set<UITouch>) {
let location = touch.locationInNode(self)
dx = pin.position.x - playerPoint!.x
dy = pin.position.y - playerPoint!.y
let length = sqrt(pow(dx!, 2) + pow(dy!, 2))
let distanceBetweenRopeNodes = 5
let numberOfPieces = Int(length)/distanceBetweenRopeNodes
var ropeNodes = [SKSpriteNode]()
//adds the pieces to the array at respective locations
for var index = 0; index < numberOfPieces; ++index{
let point = CGPoint(x: pin.position.x + CGFloat((index) * distanceBetweenRopeNodes) * sin(atan2(dy!, -dx!) + 1.5707), y: pin.position.y + CGFloat((index) * distanceBetweenRopeNodes) * cos(atan2(dy!, -dx!) + 1.5707))
let piece = createRopeNode(point)
ropeNodes.append(piece)
world.addChild(ropeNodes[index])
}
let firstJoint = SKPhysicsJointPin.jointWithBodyA(ropeNodes[0].physicsBody, bodyB: pin.physicsBody, anchor:
CGPoint(x: (ropeNodes[0].position.x + pin.position.x)/2, y: (ropeNodes[0].position.y + pin.position.y)/2))
firstJoint.frictionTorque = 1
self.physicsWorld.addJoint(firstJoint)
for var i = 1; i < ropeNodes.count; ++i{
let nodeA = ropeNodes[i - 1]
let nodeB = ropeNodes[i]
let middlePoint = CGPoint(x: (nodeA.position.x + nodeB.position.x)/2, y: (nodeA.position.y + nodeB.position.y)/2)
let joint = SKPhysicsJointPin.jointWithBodyA(nodeA.physicsBody, bodyB: nodeB.physicsBody, anchor: middlePoint)
joint.frictionTorque = 0.1
self.physicsWorld.addJoint(joint)
}
finalJoint?.frictionTorque = 1
finalJoint = SKPhysicsJointPin.jointWithBodyA(ropeNodes[ropeNodes.count - 1].physicsBody, bodyB: player.physicsBody, anchor:
CGPoint(x: (ropeNodes[ropeNodes.count - 1].position.x + playerPoint!.x)/2, y: (ropeNodes[ropeNodes.count - 1].position.y + playerPoint!.y)/2))
self.physicsWorld.addJoint(finalJoint!)
}
}
else{
physicsWorld.removeJoint(finalJoint!)
playerIsConnected = false
}
}
Anchor points are what you are looking for. Move the anchor point of the scene to only move the "camera" of the scene (what is displayed onscreen). This will not jostle the pin and rope. Keep in mind that the anchor point is on a slightly different scale from the scene.
Where the width of the scene could be 1024, the "width" of the of the anchor point for one scene length is 1 (basically counting as one width of the node). Same for the height, where it could be 768, the "height" would still be 1 in the anchor point coordinate space. So to move half a screen width, move the anchor point 0.5
The anchor point is a CGPoint, so you can go vertically as well. Here's a quick example:
var xValue : Float = 0.75
var yValue : Float = 0.0
self.scene?.anchorPoint = CGPointMake(xValue, yValue);
And for further reading, here's a link to the documentation on anchor points for sprites.