I am using SpriteKit, and my sprite is slowing as it approaches the touched point.
I would like the sprite to remain at a fixed speed as it moved from initial point to the touched point on the screen.
Currently, i have the duration set to 3.0
In the touchesEnded event, i gather the new point of the touch and save the value to a property.
In the scene update event, i perform a
float realMoveDuration = 3.0;
SKAction *actionMove = [SKAction moveTo:self.newPoint duration:realMoveDuration];
[self.player runAction:[SKAction sequence:#[actionMove]]];
So when the player sprite starts getting closer to the touch point, the movement slows down, and gradually reaches the touch point.
This is not the action I am looking for, i would like the player sprite to continue at a constant rate of travel to the touched point.
You should just run your SKAction in the touchesEnded event.
If you have that code in the update event, it's starting a new SKAction 60 times per second. You only ever need to run a new SKAction when there is a change in destination.
If there is a change in destination before you reach the original destination, you should remove the action from that node and then add a new one.
Also, not certain about the specifics of what you are doing, but how quickly an object moves is based on the distance and the time you have specified for it to get there. So if you want a node to move at a consistent speed, regardless of distance, you need to make a calculation to determine the right duration to set for your SKAction.
For example if speed represents pixels/units per second you might do this to calculate your duration :
duration = distance / speed;
If you are using an SKAction to move the sprite, use the timingMode property. The default is SKActionTimingLinear. So if you haven't changed it, the node should move at a constant speed.
Here's a link to the available Action Timing Modes.
Related
I'm trying to use an SKAction to move my sprites. However, I noticed that after moving the sprites, their position values still remained the same. With some research, I learned that (correct me if I'm wrong) the sprites' position values are actually their location relative to the parent view, and that it was the parent view's position value that had actually changed, and not the sprites'. Only when I checked, the parent view's position value also hadn't changed.
So which position value actually changes?? And how would I go about accounting for the change in position when accessing the sprites' position values? (Since a lot of my game's logic is dependent on their position values)
Here's my code:
let fall = SKAction.moveBy(x: 0, y: -85, duration: 0.2)
print("Original position \(gift.position)")
gift.run(fall)
print("New position \(gift.position)") // Both print the same value
Any help would be greatly appreciated!
Your gift.run(fall) is scheduling an action that will happen over the course of 0.2 seconds, not waiting for it to finish. At 60 frames/second, that means the sprite will reach its final position only after 12 frames. If you print the gift's position at each step in update(_:), you'll see that it is indeed changing.
Since the run does not wait for the action to complete, the sprite hasn't had a chance to move at all when the second print is executed.
If you want something to happen only after an action completes, you have various possibilities. A common way is to add a completion block; see Apple's documentation on getting started with actions: https://developer.apple.com/documentation/spritekit/getting_started_with_actions. Or if you want the same node to do multiple things in order, you can make a composite SKAction, like with the sequence or repeat initializers.
I make a 2D-game. In this game, I have a projectile, which I move the fires by myself like this:
void Update()
{
gameObject.transform.position = new Vector3(
gameObject.transform.position.x + baseVelocity * Time.deltaTime,
gameObject.transform.position.y + baseVelocity * Time.deltaTime,
gameObject.transform.position.z);
}
And also, I use void OnTriggerEnter2D(Collider2D other) to know when collisions occurs.
The problem is when game running on a weak phone with 30-FPS it won't detect collision, while same fire in an 60-FPS phone will collide.
I think this is because the fires move 2x more in 30-FPS phones.
One option was use FixedUpdate() method for moving fiers, but it gave me jerky movement, and I used Update() method for moving because it gives me smooth movement(in both of them I used Time.deltaTime).
Can you please suggest me how make more accurate while using smooth movement?
like move object in Update() method but check object position in more(offset) positions than where it is!
I forget to note that I changed the value of Fixed TimeStep to 0.01 for getting more accurate physics.
Thanks in advance.
edit:
I finally end up with using FixedUpdate() for move objects by myself, for so many reasons I can't use Physics engine, I set FixedUpdate TPS(tick per second) around 60 to some how be match with my 60 FPS Update (and still can't figure out why increase FixedUpdate TPS will make object movement jerky!).
And will keep this question open for finding better answer.
You seem to be doing the physics manually. The issue with manually updating the position is that you don't know about the position of your projectile between frames. Even if you were to use FixedUpdate, you could still be in the situation where two FixedUpdate calls cause your projectile to miss an object.
So instead of manually updating the position, you should use a RigidBody2D, with the collision detection set to "Continuous". A continuous collision detection will interpolate object collision in between physics update cycles, so you hit your target even at very high speeds. Also, this solution does not depend on frame rate.
Note that the above will only work if you don't manually update your positions yourself. That is because the physics engine uses velocity to calculate collision in between physics update cycles.
So instead of updating the position yourself (which is bad for physics), use forces instead.
Or alternatively, if you don't want to mess with forces, update the velocity instead:
GetComponent<RigidBody2D>().velocity = baseVelocity;
My main character moves by touching and holding him and then moving your finger left or right to move the character. To do this I just simply update the node's x position (walks left and right on a flat surface) in touchesMoved() with the x position of the touch location, and apply an animation depending on the direction he's moving.
I want to kind of take this to the next level and accomplish the same effect, but using physics, so that when I'm done moving him and release my finger, he may slide a little bit in the direction he was moving given the speed I was moving him at, if that makes sense. Does anyone know how I can accomplish this effect?
Would I have to do as I'm currently doing and update the position as it moves, but also apply a force/impulse at the same time? Kind of confused on how to approach this
Moving the physics body via force, impulse, or velocity will automatically update the player position.
So you will have to play around with the correct way to accomplish your goal. But based on this, what I would suggest is replace your .position code with .physicsBody!.velocity code in your touchesMoved. Then, on your touchesEnded, you can apply a bit of an impulse to give the player that little bit of an "on ice" effect to keep them going a tad.
You will need to experiment with how much velocity you want to get the character to move at the correct speed, and then you will need to play with the impulse figures as well to get it just right.
This could get a bit tricky though, in touchesMoved... because at some point you will want to reset the velocity to 0 (so they stop moving when your finger stops).
To do that, you will need to to use the .previousLocation from your touch object, and compare the distance of X moved. if the distance X moved is >0 (or some deadzone threshold) then apply the velocity; if the deltaX is 0, then set the velocity to 0.
This may actually be more complicated than just using .position to move the character, then having the character slide a bit with physics on touchesEnded.
You will have to play with it to get it right.
so I have a ball (sprite subclass) that can be dragged around the screen and updates it body to tell the world its position.
The problem is, when I apply a force to the ball while the ball is being touched (thus being controlled by a finger), I have two pieces of code fighting against each other to update the sprite's visual position.
The world stepper is trying to follow through the physics and update the ball's position. The touch methods however are also trying to update the ball's body and graphic position. Ideally, when touched I would like to kill off any physics affecting the ball.
So what exactly should I be trying to do to consolidate this? This is also creating issues for collisions and filtering. Any help appreciated. Thanks
Do you want the ball to have an accurate physics simulation? If not, you could always use the SetTransform method of the b2body class like this.
CGPoint ballLocation = ;//use the touched location for this
b2Vec2 vecBallLocation = b2Vec2(ballLocation.x / 32, ballLocation.y / 32);//calculate this on your own
b2Body * ballBody = ;//replace this variable with your ball's b2Body;
ballBody->SetTransform(vecBallLocation, ballBody->GetAngle());
Do not set the ball sprite's position manually. Leave this up to the physics simulation. Your code will get really messy over time if you have to keep track of what sprites you set the position of manually and which ones use the physics simulation to update their positions. This way is also much easier.
When the physics object is being dragged, set its velocity and angular velocity to 0,0 before running the physics step simulation. You may also want to temporarily get the physics object's position, then step, then set the body's position back, then apply whatever touch dragging offset you got from moving the finger to the body.
I currently have a SneakyJoystick up and running. It works fine, it moves the sprite around the screen. I already have it so it will flip the sprite's image when the joysticks degrees is to the left. But how do i make it so if it was moving left and then becomes inactive, the sprite won't automatically flip back? This is really confusing to me. Any help is appreciated. Thanks.
You must have a scheduled selector function in your program that checks the movement of your joystick after every second (or whatever the interval). I mean the code where you are checking if the joystick is towards left (joystick.velociy). So this selector will be called continuously, no matter your joystick is active or not. So when your joystick moves to left, you can flip the sprite and you can set define a boolean flag "isFlipped=true". And in the same selector method that you can check if joystick is not moving and "isFlipped=true" then you can flip back your sprite and set the flag false.
Generally speaking, it is advised to multiple the velocity by an arbitary amount and the delta value passed in to the update routine so that things move more smoothly. That will ensure that the final movement of the player is OK. I have seen people use a value between 50 and 200 for average movement.
eg,
CGPoint velocity = ccpMult(moveStick.velocity, 200 * delta);