We Keep Coding

Paper.js scale transform continues outside the onFrame event

I'm running into a bit of an odd issue with Paper.js - I'm using the library to scale the "petals" of a randomly generated flower while audio plays.
The issue crops up if the flower is "growing" and the user navigates to a different tab in the browser. Even though it appears that the onFrame event is not firing when the window is out of view, whichever petal is currently scaling at the time will continue to scale indefinitely.
I even tried using a special js library to determine if the window is in view and still wasn't able to get the petals to stop scaling.
You can view a demo here, as I was not even able to replicate this in a Paper sketch: https://demos2.paperbeatsscissors.com/
Also including my onFrame code here in case the problem is obvious to someone:
view.onFrame = function(event) {
// See if something is playing
if (playing > -1) {
// Get the active flower
var activeFlower = garden[playing],
activeData = activeFlower.data;
// Active layer and petal
var activeLayer = getEl(activeFlower, activeData.lIndex),
activePetal = getEl(activeLayer, activeData.pIndex);
// Variables
var time = activeData.audio.seek(),
scaleAmount = (1 / (activeData.timing / event.delta.toFixed(3))) * 2;
// Petal progression
if (!activeData.completed) {
if (activePetal.scaling.x < 1 && activePetal.scaling.y < 1) {
activePetal.pivot = {x: 0, y: activePetal.height / 2};
activePetal.scaling.x = activePetal.scaling.x + scaleAmount;
activePetal.scaling.y = activePetal.scaling.y + scaleAmount;
} else {
if (activeData.pIndex < (activeLayer.children.length - 1)) {
// If the petal is scaled, jump to a new petal
activeData.pIndex += 1;
} else {
if (activeData.lIndex > 0) {
// When all petals are bloomed, jump to a new layer
activeData.pIndex = 0;
activeData.lIndex -= 1;
} else {
// Set the flower as completed
activeData.completed = true;
}
}
}
}
activeFlower.rotate(.125, activeData.center);
// Reset the playing variable if the audio clip is complete and the flower has completed
if (!activeData.audio.playing() && time === 0 && activeData.completed) {
playing = -1;
}
}
}
Really stumped on this one so any help is greatly appreciated!

I think that your problem is coming from the fact that you base your scaling calculation on event.delta which represents the time elapsed since the last event fired.
The thing is that, if I'm not mistaken, under the hood, Paper.js onFrame event relies on requestAnimationFrame which does not fire when the tab if inactive.
So when you switch tab, wait for a while and get back to your tab event.delta value is big and your scaling value too, hence the size of your petals. This basic sketch showcase this behavior.
So in my opinion, you should simply check event.delta value and limit it if it's too high.

Why does a while loop, inside a threejs render function, not update every frame?

I have an array of 8 cubes, all 1px tall. When a button is hit, they are meant to tween to a new target height, using a while loop, like this:
if (buttonHit) {
console.log('button hit')
for (i in meshArray) {
while (Math.abs(meshArray[i].scale.y - newList[i].cost)>5) {
console.log(meshArray[3].scale.y)
meshArray[i].scale.y += .3
}
}
buttonHit = false;
}
What the console log shows me is that meshArray[3] holds at 1px 1215 times in a row, then adds .3, then stops, but the mesh just pops to it's target height once this is all done.
Does a while loop not work in the render()?

The problem is that render is called once for each frame that needs to be rendered. You are doing all your changes in one frame. threejs never has a chance redraw anything.
What you need to do is change the height by .3 only once per call to render. Ie not have it in a loop.
something a bit like this:
function render() {
if (buttonHit) {
new_height = 2;
buttonHit = false;
}
if (meshArray[i].scale.y < new_height) {
meshArray[i].scale.y +=.3
}
}

Phaser, make a button click event continuous

I'm using Phaser.js to create a map (tileSprite) and have some sprites on it, because not all the sprites can get in, I'm using the camera to pan right and left.
I want the user to either click a keyboard key (left or right) or a directional button sprite to continuously pan the camera until the user releases the control.
I've implemented keyboard panning similar to this example, I hold down a key and the camera moves/pans (10 pixels to each side on an event) and stops on key release.
However, when I've tried to implement the same thing using the 2 sprite buttons, each button fired only 1 event and panned the camera only 10 pixels per click. I need to to keep firing until I let go of the key.
var panRightButton = game.add.button(800, 5, 'right_pan_btn', onClickAction, this);
panRightButton.onInputOver.add(onButtonOver, this);
panRightButton.onInputOut.add(onButtonOut, this);
panRightButton.onInputDown.add(panScreenRight, this);
function panScreenRight() {
game.camera.x += 10;
}
I've tried using a boolean flag (isPanning) that would turn to true if i'm clicking a button and false on release. and have a while loop on game.camera.x += 10;, but it just slowed and stopped the script.
function onClickAction() {
isPanning = true;
}
function onButtonOut() {
isPanning = false;
}
function onButtonUp() {
isPanning = false;
}
function panScreenLeft() {
if (isPanning) {
game.camera.x -= 10;
}
}

The proper way to do it is on the update method, but not within a loop. Using a flag to know if the button is being pressed is ok, but just let Phaser to update the camera position, like in the example that you have linked:
function update() {
//...
if (isPanningLeft) {
game.camera.x -= 10;
} else if (isPanningRight) {
game.camera.x += 10;
}
//...
}
You don't need a loop because the update method is executed within a loop (and it is expected to be executed once by frame)

How to animate slide left smoothly?

I have the following
$('.left_arrow').hover(function() {
$('.chart').stop().animate({
left: "+=10"
});
},
function() {
$('.chart').stop();
});
And I want to have it when you mouse over the arrow it smoothly moves the .chart to the left, and the right arrow it moves it to the right. I am doing this by applying a - left (-7500px is the max) to move it to the left and a 0 is the farthest it can go right.
The above moves it over 10, but it doesn't keep on moving it. How can I get it so it keeps on moving it. I was using something like
$('.left_arrow').hover(function() {
$('.chart').stop().animate({
left: "-7500px"
}, 20000);
},
function() {
$('.chart').stop();
});
But the problem is if I am say -6500px over it takes 20 seconds to go the rest of the 1000, vs 20 seconds to go the full distance. So the speed is skewed, I want a standard increment.

Basically what you need is a rate function. I had the same issue when I was creating my carousel.
rate = distance/time
So, your rate is 0.375
Now, all you will need to do is find the distance and you can adjust your timing accordingly.
time = distance/0.375
So it should look something like this:
$('.left_arrow').hover(function() {
var distance = /*Get Distance Remaining*/
var sd = 7500;
var time = 20000;
var rate = sd/time;
var time = distance/rate
$('.chart').stop().animate({
left: "-7500px"
}, time);
},
function() {
$('.chart').stop();
});
Obviously it would need some tweaking to get just right. But the concept is there.
For my situation, because I was using a <ul> since it was a carousel this is the way I got distance:
distance = Math.abs($ul.position().left);

Not fully understanding the question, but you can increment/decrement animations like so:
$('.chart').stop().animate({
"left": "+=100px"
}, 250);
Note the += operator.
EDIT: This answer is only partially correct. Animation behavior on hover is not as desired. Trying to solve.

EaselJS SpriteSheet isn't responding to gotoAndPlay

I'm developing a Fez-based HTML5 Canvas game using EaselJS and I've found a problem, that I can't solve myself, while trying to implement SpriteSheets to the hero.
The problem is that I've defined three animations to my hero ("stand", "jump" and "run") and when I try to change from one animation to another using hero.gotoAndPlay("run") or hero.gotoAndStop("stand") the animations don't change, change but show the first frame only or change to the wrong animation.
Can someone help me? What I'm doing wrong and how can I fix it? Thanks.
Here's the relevant JavaScript code I'm using to create the hero Sprite:
var data = {
images: ["http://i.imgur.com/M0GmFnz.png"],
frames: {width:34, height:46},
animations: {
stand:0,
run:[0,12,true,0.25],
jump:13
}
};
var spriteSheet = new createjs.SpriteSheet(data);
var hero = new createjs.Sprite(spriteSheet, "stand");
hero.offset = 4 + 1; // "+1" is important, change the first number only.
hero.regX = hero.offset + 2;
hero.regY = hero.offset;
hero.width = 34 - (hero.offset*2) - 12;
hero.height = 46 - (hero.offset*2);
hero.x = 0;
hero.y = 0;
hero.jumping = true;
stage.addChild(hero);
And the code I'm using to change the animation:
if(!left && !right){ // User isn't pressing left arrow or right arrow
hero.gotoAndStop("stand");
}else{
hero.gotoAndPlay("run");
}
JSFiddle
Official Site

If you are calling gotoAndStop or gotoAndPlay in a tick (or similar) then it will constantly reset to the first frame. You have to ensure you only call these functions one time when the animation changes.
A good way to set this up is to store the current animation, store it, and only change it up if the animation changes. Something like:
var animation;
if(!left && !right){ // User isn't pressing left arrow or right arrow
animation = "stand";
}else{
animation = "run";
}
if (currentAnimation != animation) {
hero.gotoAndStop(animation);
}
This is just an example, but should give you an idea. You should only call these methods one time to kick off an animation.