I'm building an HTML5 game with Phaser 3. I have a counter tween that I add to the scene upon a certain if condition being met on click of a game object. (It is a text value that flashes red if the card's maximum stat value is lower than the player's value of that stat.)
First, I set the variable based on which card was clicked:
if (this == action1_card) {
action = action1
energy_cost = action1_energy_cost
max_suspicion = action1_suspicion_threshold
selected_card = action1_card_selected
} else if (this == action2_card) {
action = action2
energy_cost = action2_energy_cost
max_suspicion = action2_suspicion_threshold
selected_card = action2_card_selected
}
Once I have the values I want (max suspicion is the relevant variable in this case), I then apply the flashing color animation to it if the condition is met.
if (action.suspicion_threshold < game_data.player.stats.suspicion) {
t.tweens.addCounter({
from: 0,
to: 100,
duration: 250,
repeat: 1,
yoyo: true,
ease: Phaser.Math.Easing.Sine.InOut,
onUpdate: function(tween) {
const value = Math.floor(tween.getValue());
const colorObject = Phaser.Display.Color.Interpolate.ColorWithColor(
Phaser.Display.Color.ValueToColor('#000000'),
Phaser.Display.Color.ValueToColor('#FF0000'),
100,
value
)
const color = Phaser.Display.Color.RGBToString(colorObject.r, colorObject.g, colorObject.b)
max_suspicion.setColor(color);
}
});
The issue is that, if I was to click on card 1 and then card 2 before the animation was finished on card 1, the animation from card 1's text would resume on card 2. This makes sense, as the variable "max_suspicion" was reassigned to the text object on card 2, and the tween's onUpdate function is continuing as it should.
How do I either:
1) prevent this from being reassigned (e.g. setting max_suspicion to permanently represent card 1's text object for the scope of the tween)
or
2) reset card 1's value to it's original color and end the tween prematurely so it doesn't carry over to card 2?
I will gladly clarify anything as needed. Thank you so much for any help on this!
It depends on your code, what the best solution is. (and ofcourse the desired gameplay)
I personally would put the tween in a variable:
this.mytween = scene.tweens.addCounter(...);
and stop it on click before i do anything else
if(this.mytween) {// just checking if it exists
this.mytween.stop();
... // may be reset the color
}
i'm new to react native and i'm trying to do a moving arrow after a variable get a value, I thought about using a switch case and changing the style, but it seemed impossible to change the padding properties, how could i solve this?
Your question needs a lot of information to be answered thoroughly so I will assume you use hooks, I will try to guide you by giving you an example.
The whole principle is to place your arrow in an 'absolute' position and animate it with an animation. Then, all you need to do is to set the value of the variable 'arrowValue', example : setArrowValue(0.3). Your arrow will then places itself at 30% (according to your interpolation) from the left of your container.
Here is a code snippet to show you the right way :
import {StyleSheet, View, Animated} from "react-native";
export default function ArrowMover(props)
{
// This is the value you will set and your arrow will automatically be placed
const [arrowValue, setArrowValue] = React.useState(0); // From 0 to 1 for example
// This is your animation
// It is the value you have to change to make your arrow move
const [animation, setAnimation] = React.useState(new Animated.Value(0));
// This is an interpolation of your animation
// See this as a black box, it allows you to output value (and ranges of values)
// based on the value of your animation
const animateArrowPosition = animation.interpolate({
inputRange: [0, 1],
outputRange: ["0%", "100%"],
});
// This is where everthing happens automatically
React.useEffect(() =>
{
moveArrowTo(arrowValue);
}, [arrowValue]); // Anytime 'arrowValue' changes, execute the 'moveArrowTo' function
const moveArrowTo = (newArrowValue) =>
{
Animated.timing(animation, { toValue: newArrowValue, duration: 500, }).start(() =>
{
// Do something (or nothing) once the animation finished
});
};
return(
<View style={s.container}>
// Your animation interpolation will change along with 'animation' to follow your interpolation
// of the value
<Animated.View style={[s.arrow, {left:animateArrowPosition}]}> // Notice the 'Animated.View'
<View>
// Your arrow (icon, image, etc...)
</View>
</Animated.View>
</View>
);
}
let s = StyleSheet.create(
{
container:
{
// Your container style
},
arrow:
{
// Your arrow style
height:30,
aspectRatio:1,
position:'absolute',
// left:0 (no need for that, your animation is taking care of the 'left' property
},
}
I have an issue with, what I think it may be, an order of evaluation issue - but I can't figure it out exactly.
The code runs in a react-native environment, but the function is pure JS, so it can be run in browsers as well.
So, I have made a small function that creates a color representation in hsla() format. It does not return the string value directly, instead, it returns a function that uses the initial h,s,l,a values, and it accepts further overrides for l and a so I can tweak them in place. The function is below:
function Color(h, s, l, a) {
return (L, A) => {
let LL = (l || 0) + (L || 0);
if (LL < 0) { LL = 0; }
if (LL > 100) { LL = 100 }
return `hsla(${h || 0},${s || 0}%,${LL}%,${A || a || 1.0})`;
}
};
The problem is it behaves differently over the alpha value between the browser environment and the react-native environment. Specifically, when I try to do this:
var blue=Color(240,100,50);
var semiTransparentBlue = blue(0, 0.5); // 0 lightness adjustment, 0.5 alpha opacity
console.log("The hsla representation of the color is:",semiTransparentBlue);
in a browser environment, it correctly returns the string "hsla(240,100%,50%,0.5)".
In react-native however:
import React from "react";
import { View, Text } from "react-native";
import Color from "../libs/Color.js"; // the Color function is exported as-is in this file
export default class coloredComponent extends React.Component{
render = ()=>{
var blue=Color(240,100,50);
var semiTransparentBlue = blue(0, 0.5); // 0 lightness adjustment, 0.5 alpha opacity
// the above color function returns `"hsla(240,100%,50%,1)"`
// instead of `"hsla(240,100%,50%,0.5)"`, wrong alpha value
console.log("The hsla representation of the color is:",semiTransparentBlue);
return <View style={{ flex: 1, backgroundColor: semiTransparentBlue }} />
}
it returns "hsla(240,100%,50%,1)".
Adding console.log()s in the returned function shows that I do not get undefined values for either the L or A params (in the returned color function). Actually, it does not return at all any different alpha value than 1, I tried with 0.0, 0.1, and others, it always returns 1 for the alpha.
Can anyone help me figure out what's wrong ?
I am using React/Redux and am storing animation data in JSON and trying to get it to display on a React page.
I am using setTimeout (for pauses) and setInterval (for animation movement). However, I seem to be having trouble understanding how to implement the animations correctly and think I'm going about things totally the wrong way.
JSON data:
"objects": [
{
"title": "puppy",
"image_set": [
{
"image": "images/puppy_sitting.png",
"startx": 520,
"starty": 28,
"pause": 1000
},
{
"image": "images/puppy_walking.png",
"startx": 520,
"starty": 28,
"endx": 1,
"endy": 1,
"time": 1000
},
{
"image": "images/puppy_crouching.png",
"startx": 1,
"starty": 1,
"endx": 500,
"endy": 400,
"time": 2000
}
]
},
{
"title": "scorpion",
"image_set": [
{
"image": "images/scorping_sleeping.png",
"startx": 100,
"starty": 400,
"pause": 5000
},
{
"image": "images/scorpion_walking.png",
"startx": 100,
"starty": 400,
"endx": 500,
"endy": 400,
"time": 7000
},
{
"image": "images/scorpion_walking.png",
"startx": 500,
"starty": 400,
"endx": 100,
"endy": 400,
"time": 2000
},
{
"image": "images/scorpion_walking.png",
"startx": 100,
"starty": 400,
"endx": 200,
"endy": 400,
"time": 7000
},
{
"image": "images/scorpion_walking.png",
"startx": 200,
"starty": 400,
"endx": 100,
"endy": 400,
"time": 1000
}
]
}
]
Each object can have several images related to them. The animations will continue to repeat non-stop. Each object should move concurrently with each of the other objects so that I can create a scene of various animals and objects moving around it.
Animation code:
I'm pretty sure I'm barking up the wrong tree here, but my code looks something like this:
// image_set is the list of images for a specific object
// object_num is the array index corresponding to the JSON objects array
// selected is the array index corresponding to which image in the image_set will be displayed
runAnimation(image_set, object_num, selected){
// Uses prevState so that we keep state immutable
this.setState(prevState => {
let images = [...prevState.images];
if (!images[object_num]){
images.push({image: null, x: 0, y: 0})
}
images[object_num].image = image_set[selected].image;
images[object_num].x = this.getFactoredX(image_set[selected].startx);
images[object_num].y = this.getFactoredY(image_set[selected].starty);
return {images: images};
})
if (image_set[selected].endx && image_set[selected].endy && image_set[selected].time){
let x = this.getFactoredX(image_set[selected].startx)
let y = this.getFactoredY(image_set[selected].starty)
let startx = x
let starty = y
let endx = this.getFactoredX(image_set[selected].endx)
let endy = this.getFactoredY(image_set[selected].endy)
let time = image_set[selected].time
let x_increment = (endx - x) / (time / 50)
let y_increment = (endy - y) / (time / 50)
let int = setInterval(function(){
x += x_increment
y += y_increment
if (x > endx || y > endy){
clearInterval(int)
}
this.setState(prevState => {
let images = [...prevState.images]
if (images[object_num]){
images[object_num].x = x
images[object_num].y = y
}
return {images: images};
})
}.bind(this),
50
)
}
if (image_set[selected].pause && image_set[selected].pause > 0){
selected++
if (selected == image_set.length){
selected = 0
}
setTimeout(function() {
this.runAnimation(image_set, object_num, selected)
}.bind(this),
image_set[selected].pause
)
}
else {
selected++
if (selected == image_set.length){
selected = 0
}
setTimeout(function() {
this.runAnimation(image_set, object_num, selected)
}.bind(this),
50
)
}
}
Redux and this.props.data
Redux brings in the data as props. So, I have a function called from my componentDidMount and componentWillReceiveProps functions that passes the original image set into the loadAnimationFunction.
My render()
In my render() function I have something like this:
if (this.state.images.length > 1){
animated = this.state.images.map((image, i) => {
let x_coord = image.x
let y_coord = image.y
return (
<div key={i} style={{transform: "scale(" + this.state.x_factor + ")", transformOrigin: "top left", position: "absolute", left: x_coord, top: y_coord}}>
<img src={`/api/get_image.php?image=${image.image}`} />
</div>
)
})
}
x_factor / y_factor
Throughout my code there is also reference to x and y factor. This is because the background that the animations appear in may be scaled smaller or larger. Therefore I also scale the position of the starting and ending x/y coordinates for each animation as well as scale the animated images themselves.
time and pause time
Time indicates the time in ms that the animation should take. Pause time indicates how long in ms to pause before moving to the next animation.
The problem
The code does not move the animations smoothly and they seem to jump around sporadically.
Also, when I click the mouse anywhere on the page it causes the animations to jump to another position. Why would clicking the mouse affect the animation?
One thing I've noticed is that if I have the console open for debugging purposes, this really slows down the animations.
What can I do to my code so that the animations work as expected?
You are trying to animate your element using a setInterval doing a setState of the coordinates and with an absolute position. All of these cannot achieve great performance.
First, setInterval should never be used for animations, and you should prefer requestAnimationFrame as it will allow 60fps animations since the animation will be run before the next repaint of the browser.
Second, doing a setState would re-render your whole component which could potentially have an impact on the rendering timing as I assume your component doesn't render only your images. You should try to avoid at maximum to re-render things that haven't changed, so try to isolate your images for the animations.
Lastly, when you position your element with left and top properties, but you should stick to that, positioning, and not animating as the browser would do the animation pixel by pixel and would not be able to create good performances. Instead, you should use CSS translate(), as it can do sub-pixel calculation and will work on the GPU instead, allowing you to achieve 60fps animations. There is a good article on that by Paul Irish.
That being said, you should probably use react-motion which would allow you a smooth animation:
import { Motion, spring } from 'react-motion'
<Motion defaultStyle={{ x: 0 }} style={{ x: spring(image.x), y: spring(image.y) }}>
{({ x, y }) => (
<div style={{
transform: `translate(${x}px, ${y}px)`
}}>
<img src={`/api/get_image.php?image=${image.image}`} />
</div>
)}
</Motion>
There is also the React Transition Group, Transition could move your elements using a translate animation like explained above. You should also go take a look at the react animations docs here.
Worth a try too, is React Pose, which is pretty easy to use and also performs quite well with a clean API. Here is the get started page for React.
Here is a quick demo using your concept with a sit/walking/running cycle. Notice how react-motion is the only one to handle the transition in between the frames without hardcoding the duration of the transition, which would go against a fluid UI, the state only handles going through the different steps.
Quoting the react-motion Readme:
For 95% of use-cases of animating components, we don't have to resort to using hard-coded easing curves and duration. Set up a stiffness and damping for your UI element, and let the magic of physics take care of the rest. This way, you don't have to worry about petty situations such as interrupted animation behavior. It also greatly simplifies the API.
If you are not satisfied with the default spring, you can change the dampling and stiffness parameters. There's an app which could help you get the one which satisfy you the most.
Source
React is not exactly meant to be used for animations. I'm not saying you can't animate react components, but it's not part of the problem domain react tries to solve. What it does do is provide you with a nice framework to have the several UI pieces interact with each other. I.e. when creating a game for instance, you'll use react and redux to create and manage the screens, buttons etc. however the game itself, would be separately contained and not use react.
Just a long-winded way to say that if you want to use animations react will not suffice, it's better to use something like greensock's animation library: https://greensock.com/
They provide a tutorial on how to use it in conjunction with react: https://greensock.com/react
Let css do the transitions. Use transform: translate instead of top and left.
The animations you have in your sample are very easy to express with css transition, transition-delay, and transform.
I would put my effort in converting the JSON to css (using a cssInJs solution that allows you to generate the classes on the fly) and apply those classes to the images.
something like this(working example with your JSON sample): https://stackblitz.com/edit/react-animate-json
const App = () =>
<div>
{objects.map(object =>
<Item item={object} />)
}
</div>
Item.js:
class Item extends React.Component {
state = { selected: 0, classNames: {} }
componentDidMount() {
this.nextImage();
this.generateClassNames();
}
generateClassNames = () => {
const stylesArray = this.props.item.image_set.flatMap((image, index) => {
const { startx, starty, endx = startx, endy = starty, time } = image;
return [{
[`image${index}_start`]: {
transform: `translate(${startx}px,${starty}px)`,
transition: `all ${time || 0}ms linear`
}
}, {
[`image${index}_end`]: { transform: `translate(${endx}px,${endy}px)` }
}]
});
const styles = stylesArray.reduce((res, style) => ({ ...res, ...style }), {})
const { classes: classNames } = jss.createStyleSheet(styles).attach();
this.setState({ classNames });
}
nextImage = async () => {
const { image_set } = this.props.item;
let currentImage = image_set[this.state.selected];
await wait(currentImage.pause);
await wait(currentImage.time);
this.setState(({ selected }) =>
({ selected: (selected + 1) % image_set.length }), this.nextImage)
}
render() {
const { selected, classNames } = this.state;
const startClassName = classNames[`image${selected}_start`];
const endClassName = classNames[`image${selected}_end`];
return <img
className={`${startClassName} ${endClassName}`}
src={this.props.item.image_set[selected].image}
/>
}
}
const wait = (ms) => new Promise(res => setTimeout(res, ms));
I believe that your fundamental problem lies in the way React/Redux handle state. React may batch multiple update requests together to make rendering more efficient. Without further diagnostic measures, my guess is that the state handling after setState will just respond too rigidly.
The solution would to update your animation outside the state system, either using a ready-made framework or simply by taking care of the animation yourself; get a reference to the element and update it instead of re-rendering the element every time the state is updated.
without going deep about animations in JS (there are already plently of valid answers here) you should consider how you render your images:
<div key={i} style={{transform: "scale(" + this.state.x_factor + ")", transformOrigin: "top left", position: "absolute", left: x_coord, top: y_coord}}>
<img src={`/api/get_image.php?image=${image.image}`} />
</div>
You should actually see a warning when compiling this (or was it in the docs?) because you use the loop index as the key. This should lead to an image object being rendered in different divs as more images are added/removed. This is especially critically if you have a css-transition effect on the div.
TLDR: use some identifier as the key instead of the variable i (may be generate one when you create the animation?)
Also if you have a css transition on the div, you should remove it, because together with the changes from setInterval the transition calculation won't be able to keep up with the changes.
I've cobbled together this little sandbox to demonstrate: https://codesandbox.io/s/64xv97y45n
The purple div in the upper left hand corner is supposed to move as letters are typed. When a letter is typed, the currIndex (the currently active box) value on the redux store is incremented or decremented accordingly. The reducer then uses currIndex to compute the currentCoords or the div's new absolute position (for the purposes of attached sandbox, 'slightly more to the right'). The currentCoords store property is then passed on as a prop to control the dynamic pose of the purple div. But the div refuses to update its pose. Redux DevTools tells me currentCoords is updating properly, or at least well enough for it to move a little. What gives?
Relevant logic:
const reducer = (state = initState, action) => {
switch (action.type) {
case "KEYPRESS":
return {
...state,
number: [...state.number, action.key],
currIndex: ++state.currIndex,
currentCoords: state.boxCoords[state.currIndex]
};
<SNIP>
const Cursor = posed.div({
visible: {
opacity: 1,
x: ({ xPos }) => xPos,
y: ({ yPos }) => yPos
},
hidden: {
opacity: 0
}
});
<SNIP>
<Cursor
className="cursor"
initialPose="visible"
xPos={this.props.currentCoords.x}
yPos={this.props.currentCoords.y}
/>
If you want to transition your posed element without changing the current pose you need to pass a poseKey to react on. Also according to documentation of initialPose property:
Once the component mounts, it will transition from this pose into pose.
That is why have must pass pose property to the posed component otherwise initialPose will be reset. So basically <Cursor> component should be rendered like this:
<Cursor
className="cursor"
initialPose="visible"
pose="visible" // you can hold the pose in your state and use it here like this.state.pose
poseKey={this.props.currentCoords.x}
xPos={this.props.currentCoords.x}
yPos={this.props.currentCoords.y}
/>