I am trying to explore the limits of what we are consciously aware of ... okay that sounds terribly pretentious, basically how long something has to be visible for for us to notice. But I cannot get my child to disappear fast enough.
valueX = SKLabelNode(fontNamed: "ArialRoundedMTBold")
valueX.position = CGPoint(x: 0, y: 0)
valueX.fontSize = 320
valueX.text = String("H")
valueX.fontColor = SKColor.white
self.addChild(valueX)
valueX.run(SKAction.scale(to: 0, duration: 0.00001))
This should be too fast to see, but it seems to stay for around a second. Is there some other technique I can use to make something appear very briefly?
I don't think that the SK engine will scale the sprite in-between draws i.e. screen refreshes, so it'll have to be on screen at full size for at least 1 frame, which is 1/60s. I suspect that the SK engine then works out how much to scale per frame, so in the next frame it's probably completely gone. E.g. if you wanted to scale to 25% over 1 second, SK would think that it's been 0.01666667s since the last draw, so the amount to scale by is 1/60 x 75% = 1.25%.
If the duration of the action is less than the time per frame, the effect will be 100% one frame and 0% the next.
If you research 'human persistence of vision' you'll find a lot of information (which I've not gone into myself), which may be why it appears to 'stay for around a second' rather than just 1/60s
As a very basic check, put a sprite on screen in didMoveTo(:view) at a random point then move it to a random point in update(), so it'll move every time update() runs (every 1/60s). If you see it flickering around, you'll know that you can perceive something appearing for 1/60th second but you won't be able to get this done any faster.
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I am animating some frames of a monster jumping and swinging a sword, and the frames are such that the width gets bigger or smaller as he swings the sword (the monster standing is 500 width, but his sword, fully extended to the left, adds another 200 width, thus he varies from 500 to 700 or more in width)
I originally took each frame, which is on a transparent background, and used the Photoshop magic wand tool to select just the monster. I then saved these frames like that, and when I used them to animate, the monster warped and changed sizes (it looked bad).
The original frames had a large 1000 x 1000 transparent background surrounding him, and as a result it always kept him "bound" so that it never warped.
My question is what is a good way to create frames of animation where the sprite inside might change size or width as he's moving so that there is no warping?
If I have to use a large border of transparent pixels, is that the recommended approach? I'm noticing that for my animation, each monster takes up about 3 - 5MB. I plan on potentially having a lot of these people ultimately, so i'm wondering if this is the best approach (using large 900 x 900 images all the time, plus I'll be using more for 2x and 1x). So all of this seems like it could spiral out of control to 4 or 5GB.
What are other people doing when making animations that require different poses and positions? Just fixing the frames with borders that are as small as possible?
Thanks!
You should probably change the approach to animation and use inverse kinematics instead. Take a look at this and Ray's tutorial.
I'm fairly new to swift, and have been working on a game for fun, and i'm running into something I can't quite get my head around.
When the run button is pressed, the character moves forward with the following function
func move(dt: CGFloat) {
position.x += moveRate * dt
}
And when the jump button is pressed, the character jumps with the following function
func jump() {
physicsBody?.applyImpulse(CGVector(dx: 0, dy: jumpRate))
run(jumpAnimation!)
}
both work fine, but consider this senario. The player is running, and then they jump while still moving. While in the air, the player releases the move button and the player's x position stops dead. This obviously feels very unnatural, and i would like the player's x position to ease out.
Now i have also played with moving the character with physicsBody?.applyForce(CGVector(dx: 1000, dy: 0)) which would give that effect, but he seems to just gain more and more speed and you don't get a constant rate or "max speed" so to speak.
Could anybody share some insight with me? I'd love to learn anything I can about spritekit and game development in general. Thanks!
You should try to set the velocity instead of setting the X position. When setting the position you bypass all the physics behaviors.
You should also try to set it only when you actually press a button.
func move(dt: CGFloat) {
if Math.abs(moveRate) > 0.1 { // If player initiates movement. You can increase the value 0.1 if you want to filter move values
velocity = CGVector(dx: moveRate, dy: veloxity.dy)
}
}
It your character moves indefinitely like in space, linearDamping will be useful. it's used to simulate air friction, so values closer to 1 means more friction and values closer to 0 means less friction.
linearDamping = 0.85
Also, this way, moveRate isn't dt dependent but it should be lowered.
Try it, I haven't tested it yet, but that's basically how I would do it.
There are two schools of thought on platformer game "physics".
Don't use physics, do everything with positional incrementation.
Do everything with physics, since positional changes mess up physics
Since you're using physics for jumping, and physics jumping is fun:
There are three ways to create movement in a physics system:
Set the velocity as and when required. This is what Crazyrems is suggesting
Apply impulses as needed to increase and decrease rates of movement
Apply forces over time that increase or decrease rates of movement
Use fields to induce motion (too complex for this, and messy, but fun)
What you're attempting, with your physicsBody?.applyForce(CGVector(dx: 1000, dy: 0)) is the application of force over time. Number 3 in the list above. The longer you continue applying this force the faster the character moves.
Each of these techniques can be made to work, but they all need compensation for their various limitations and methodologies of simulation.
In the case of your approach, you need monitor speed and to set a maximum speed. Having reached maximum speed, if the player is still holding the button, only provide enough force to maintain speed (assuming you're using some form of constant resistance to slow the character).
Monitoring speed combined with force-over-time creates interesting acceleration trait possibilities - like very strong initial acceleration and then taper off acceleration as the player nears their maximum speed.
Slowing down when the player releases the button is the next focus. In all these approaches you need something that slows the player. This can be the application of opposing forces, or the use of friction or damping, as provided by the physics engine.
I have a scene where my gameplay happens. I'm looking for a way to slowly 'zoom-out' so more and more space becomes visible as the time passes. But I want the HUD and some other elements to stay the same size. It's like the mouse wheel functionality in top-down games.
I tried to do it with sticking everything into display groups and transitioning the xScale, yScale. It works visually of course but game functionality screws up. For example I have a spawner that spawns some objects, its graphics gets scaled but spawner still spawns the objects from its original position, not the new scaled position..
Do I need to keep track of every X, Y position I'm using during gameplay and transition them too? (Which is probably possible but too hard for me since I use a lot of touch events for aiming and path creating etc.) Or is there an easier way to achieve this? Please please say yes :P
I'm looking forward for your answers, thanks in advance! :)
The problem is you are scaling your image, but not your position coordinates.
You need to convert from 'original coordinates' to 'scaled coordinates'
If you scale your map size to half, you should scale the move amounts by half too.
You need to 'scale' your coordinates in the same amount your image is scaled.
For example lets assume your scale factor is 0.5, you have an image:
local scaleFactor = 0.5
image.xScale = scaleFactor
image.yScale = scaleFactor
Then you would need to scale your move amounts by this factor
thingThatIsMoved.x = thingThatIsMoved.x + (moveAmount * scaleFactor)
thingThatIsMoved.y = thingThatIsMoved.y + (moveAmount * scaleFactor)
I hope this helps, I am assuming you have a moveAmount variable and updating the position on the enterFrame() event.
I have an object that is moving very fast (max velocity 900). When it reaches max speed it starts to create trailing objects or motion blur.
But I just want it to be the object moving fast. I am running on 60 fps.
I like the speed of the object but I don't like how its getting rendered (motion blur). How do I handle this?
This object bounces all around the screen with a restitution of 1.02, because I want to make it pick up speed as it keeps bouncing. I want to make it go faster thats why I did the 1.02 restitution.
The motion blur may simply be due to the LCD display having an "afterglow". So the position the object was in the previous frame is still a little brighter in the next frame because it takes some time for the crystals inside the LCD to return to the unlit state.
This causes "motion blur" on any moving object on the screen, and is of course more noticeable the faster the object moves. You may even be able to make out multiple versions of the same objects at different light levels trailing behind the object's position.
This effect may also depend somewhat on the device and model, and is often called 'ghosting'.
Regardless, there's nothing you can do about the "motion blur" caused by the LCD screen's afterglow effect. Here's a good article explaining the effects and their causes.
Hmm... you'll have trouble getting it to render smoothly.
At that speed (900 points per second) it will move 15 points every FRAME if running at 60 fps. That's a significant amount to move in such a short amount of time. In about 1/3 of a second it will travel entirely across the screen.
I'm guessing it will be getting to the limit of the ability of the hardware. Both the processor, the screen and your actual eyes. I imagine you'll also hit physics errors too with it possibly escaping through walls etc...
Can you show a video of how it is currently behaving?
I'm trying to move a sprite around a CCTMXMap in a smooth fashion. I've figured out how (using CCActions) to move from tile to tile, but I get gaps in my animation (it pauses for a frame while it reevaluates which direction to walk). I've tried moving the character in a scheduled update: method, but that gets messy when you try and restrict the sprite to only moving from tile to tile. Any suggestions on how to get the clean, consistent animation without messy manual animation using update?
Yes, don't use actions. You'll always have the 1-frame delay problem when using CCActions.
Moving the sprite in update is really pretty simple. Especially if you restrict movement to a speed (points per frame) that is clearly divisible by the tile size. For example if your tiles are 40x30, then horizontal speeds of 1,2,4,8,10 would work fine. Vertically 1,2,3,5,6,10 would work.
Update the position by this number, cast it down to int, compare it with the destination location:
if ((int)currentPos.x == (int)targetPos.x && (int)currentPos.y == (int)targetPos.y)
{
NSLog(#"I'm there!");
}
The reason for casting to int is to avoid rounding errors in floating point values.
Another solution would be - especially if your character can only move in one direction at a time - to figure out the number of frames it will take him to get there. If the character has to move 40 points to the right, and he moves at 4 points per frame, it'll take him 10 frames. Then just count the number of frames (how many times the update method ran) and if it reaches 10 (or 0 if you count down) then you know that the character has arrived without needing to check his position.