I'm currently using Phaser 3, although my question isn't technically restricted to that framework, as it's more of a general JS/canvas/maths question, but:
I have a line drawn with graphics(). It’s anchored at one end, and the other end is draggable. I made a quick demo and so far, so good - you can see what I have already on CodePen.
Dragging the marker around and redrawing the line is no problem, but what I’d like is for that line to have a maximum length of 100, so even if you’re still dragging beyond that point, the line would still follow the mouse, but not get any longer than 100. Dragging inside that maximum radius, the line would shrink as normal.
I’ve put together a visual that hopefully explains it:
The issue is that I suspect this is VERY MATHS and I am very, very weak with maths. Could anyone explain like I’m five what I need to do to my code to achieve this?
Edit: Adding code in a snippet here, as requested:
var config = {
type: Phaser.AUTO,
width: 800,
height: 400,
backgroundColor: '#2d2d2d',
parent: 'phaser-example',
scene: {
preload: preload,
create: create,
update: update
}
};
var path;
var curve;
var graphics;
var game = new Phaser.Game(config);
function preload() {
this.load.spritesheet('dragcircle', 'https://labs.phaser.io/assets/sprites/dragcircle.png', { frameWidth: 16 });
}
function create() {
graphics = this.add.graphics();
path = { t: 0, vec: new Phaser.Math.Vector2() };
curve = new Phaser.Curves.Line([ 400, 390, 300, 230 ]);
var point0 = this.add.image(curve.p0.x, curve.p0.y, 'dragcircle', 0);
var point1 = this.add.image(curve.p1.x, curve.p1.y, 'dragcircle', 0).setInteractive();
point1.setData('vector', curve.p1);
this.input.setDraggable(point1);
this.input.on('drag', function (pointer, gameObject, dragX, dragY) {
gameObject.x = dragX;
gameObject.y = dragY;
gameObject.data.get('vector').set(dragX, dragY);
});
this.input.on('dragend', function (pointer, gameObject) {
let distance = Phaser.Math.Distance.Between(curve.p0.x, curve.p0.y, curve.p1.x, curve.p1.y);
console.log(distance);
});
}
function update() {
graphics.clear();
graphics.lineStyle(2, 0xffffff, 1);
curve.draw(graphics);
curve.getPoint(path.t, path.vec);
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/phaser/3.55.2/phaser.min.js"></script>
You are right, you would need some math, but phaser has many helper functions, that will do the heavy lifting.
The main idea is, of this solution is
define a maxLength
get the the new point on drag, and create a real Phaser Vector2
here is some math is needed, to create the vector, just calculate destination point minus origin point
new Phaser.Math.Vector2(pointer.x - point0.x, pointer.y - point0.y) (origin point being the starting point of the desired vector, and destination point being the mouse pointer)
calculate the length of the created vector and compare it with the maxLength
if too long adjust the vector, with the handy function setLength (link to the documentation, this is where you would have needed math, but thankfully Phaser does it for us)
set the new coordinates for point1 and the curve endpoint
Here a quick demo (based on your code):
var config = {
type: Phaser.AUTO,
width: 500,
height: 170,
scene: {
preload: preload,
create: create,
update: update
}
};
var curve;
var graphics;
var game = new Phaser.Game(config);
function preload() {
this.load.spritesheet('dragcircle', 'https://labs.phaser.io/assets/sprites/dragcircle.png', { frameWidth: 16 });
}
function create() {
graphics = this.add.graphics();
curve = new Phaser.Curves.Line([ config.width/2, config.height - 20, config.width/2, 10 ]);
// define a length, could be a global constant
let maxLength = curve.p0.y - curve.p1.y;
var point0 = this.add.image(curve.p0.x, curve.p0.y, 'dragcircle', 0);
var point1 = this.add.image(curve.p1.x, curve.p1.y, 'dragcircle', 0).setInteractive();
this.input.setDraggable(point1);
// Just add for Debug Info
this.add.circle(curve.p0.x, curve.p0.y, maxLength)
.setStrokeStyle(1, 0xffffff, .5)
this.input.on('drag', function (pointer) {
let vector = new Phaser.Math.Vector2(pointer.x - point0.x, pointer.y - point0.y);
let distance = Phaser.Math.Distance.Between( point0.x, point0.y, pointer.x, pointer.y);
if(distance > maxLength){
vector.setLength(maxLength);
}
point1.x = point0.x + vector.x;
point1.y = point0.y + vector.y;
curve.p1.x = point1.x;
curve.p1.y = point1.y;
});
// NOT REALLY NEEDED
/*this.input.on('dragend', function (pointer, gameObject) {
let distance = Phaser.Math.Distance.Between(curve.p0.x, curve.p0.y, curve.p1.x, curve.p1.y);
console.log(distance);
});*/
}
function update() {
graphics.clear();
graphics.lineStyle(2, 0xffffff, 1);
curve.draw(graphics);
}
<script src="https://cdn.jsdelivr.net/npm/phaser#3.55.2/dist/phaser.js"></script>
Optional - Code Version using Phaser.GameObjects.Line:
This uses less code, and thanks to the Line GameObject (link to Documentation), you can directly use the vector to update the line, and also don't need the update function, graphics and so.
const config = {
type: Phaser.CANVAS,
width: 500,
height: 160,
scene: {
create
}
};
const game = new Phaser.Game(config);
const MAX_LINE_LENGTH = 100;
function create() {
let points = [ {x: config.width/2, y: config.height - 20}, {x: config.width/2, y: config.height - 120} ];
let point0 = this.add.circle(points[0].x, points[0].y, 6)
.setStrokeStyle(4, 0xff0000);
let point1 = this.add.circle(points[1].x, points[1].y, 6)
.setStrokeStyle(4, 0xff0000)
.setInteractive();
this.input.setDraggable(point1);
// Just add for Debug Info
this.add.circle(point0.x, point0.y, MAX_LINE_LENGTH)
.setStrokeStyle(1, 0xffffff, .5);
let line = this.add.line(points[0].x, points[0].y, 0, 0, 0, -100, 0x00ff00)
.setOrigin(0);
this.input.on('drag', function (pointer) {
let vector = new Phaser.Math.Vector2(pointer.x - point0.x, pointer.y - point0.y);
let distance = Phaser.Math.Distance.Between( point0.x, point0.y, pointer.x, pointer.y);
if(distance > MAX_LINE_LENGTH){
vector.setLength(MAX_LINE_LENGTH);
}
point1.x = point0.x + vector.x;
point1.y = point0.y + vector.y;
line.setTo(0, 0, vector.x, vector.y);
});
}
<script src="//cdn.jsdelivr.net/npm/phaser#3.55.2/dist/phaser.js"></script>
Related
So I have been using the Chebyshev Distance example from the Phaser labs, and while this example was using one layer, I happen to be using two, and when i set transparency on them, the colors start leaking into each other, especially on light colors.
Is there any way to circumvent or get rid of this effect
If the problem is that you have two layers, one ontop of the other and you are making both transparent (or only the top one), and you don't want that color to pass through, the solution could be to hide the tiles on the bottom layer.
Just check in the map-tile-loop, if the tile, where you want to change the alpha, has a tile beneath it, and if so make that background tile transparent.
Here a small working demo:
(The main magic is in the updateMap function)
document.body.style = 'margin:0;';
var config = {
type: Phaser.AUTO,
width: 536,
height: 183,
scene: {
preload,
create
}
};
var player;
var bgLayer;
var point1 = {x: 250, y: 31};
var isLeaking = false;
new Phaser.Game(config);
function preload (){
this.load.image('tiles', 'https://labs.phaser.io/assets/tilemaps/tiles/catastrophi_tiles_16.png');
this.load.tilemapCSV('map', 'https://labs.phaser.io/assets/tilemaps/csv/catastrophi_level2.csv');
}
function create () {
this.add.text(50, 1, ' <- Background is visible, if no tiles are ontop')
.setOrigin(0)
.setDepth(100)
.setStyle({fontFamily: 'Arial'});
this.infoText = this.add.text(10, 20, 'Click to toggle leaking: on')
.setOrigin(0)
.setDepth(100)
.setStyle({fontFamily: 'Arial'});
// Just creating image for second layer tiles //
let graphics = this.make.graphics();
graphics.fillStyle(0xff0000);
graphics.fillRect(0, 0, 16, 16);
graphics.generateTexture('tiles2', 16, 16);
// Just creating image for second layer tiles //
let map = this.make.tilemap({ key: 'map', tileWidth: 16, tileHeight: 16 });
let tileset = map.addTilesetImage('tiles');
let tileset2 = map.addTilesetImage('tiles2');
bgLayer = map.createBlankLayer('background', tileset2);
bgLayer.fill(0);
let fgLayer = map.createLayer(0, tileset, 0, 0);
// Just to show that the Background is still show if not Tile is covering
fgLayer.removeTileAt(0, 0);
fgLayer.removeTileAt(1, 0);
fgLayer.removeTileAt(2, 0);
player = this.add.rectangle(point1.x, point1.y, 5, 5, 0xffffff, .5)
.setOrigin(.5);
this.input.on('pointerdown', () => {
isLeaking = !isLeaking;
this.infoText.setText( `Click to toggle leaking: ${isLeaking?'off':'on'}` )
updateMap(map);
});
updateMap(map);
}
function updateMap (map) {
let originPoint1 = map.getTileAtWorldXY(point1.x, point1.y);
console.info(map.layers.sort((a,b) => b.depth - a.depth))
map.forEachTile(function (tile) {
var dist = Phaser.Math.Distance.Chebyshev(
originPoint1.x,
originPoint1.y,
tile.x,
tile.y
);
let bgTile = bgLayer.getTileAt(tile.x, tile.y, false)
let hideOnlyTheseTiles = [ 0, 1, 2, 3, 4]; // Indexes to hide
if( !isLeaking ){
if(hideOnlyTheseTiles.indexOf(bgTile.index) > -1){ // here yopu can select the
bgTile.setAlpha(0);
}
} else{
bgTile.setAlpha(1);
}
tile.setAlpha(1 - 0.09 * dist);
});
}
<script src="//cdn.jsdelivr.net/npm/phaser#3.55.2/dist/phaser.js"></script>
I would like to randomly spawn a sprite when an enemy dies.
Example: There is a 1 in 5 chance that when an enemy dies, it drops an object (sprites that increase your HP).
Any idea how this can be done?
I did some research, but I didn't find much.
For randomness in a Phaser application, I would use the Phaser's Math helper function Between (here is the link to the documentation).
It creates a random number (whole number) from the first number to the last one (including the last number, perfect for dice).
So for 1 in 5, you just need to select one number from the interval like 5and compare it with a call to the Between function. And only if it matches, you drop/create the sprite.
Just like this:
if(Phaser.Math.Between(1, 5) === 5){
// .. drop "loot" / health-object
}
Here a small Demo:
(In this demo something could be dropped or not, depending on your luck. 20% is pretty low)
document.body.style = 'margin:0;';
var config = {
type: Phaser.AUTO,
width: 536,
height: 183,
scene: {
create
},
banner: false
};
function create () {
this.add.text(10, 10, 'Click to red Boxes')
let graphics = this.make.graphics({x: 0, y: 0, add: false});
graphics.fillStyle(0xFF0000);
graphics.fillRect(0, 0, 20, 20);
graphics.generateTexture('enemy', 20, 20)
let enemiesGroup = this.add.group({
defaultKey: 'enemy',
maxSize: 10
});
let maxEnemiesToShow = 10
for(let idx = 0; idx < maxEnemiesToShow; idx++){
// here the function is used to spawn enemies randomly on screen
const x = Phaser.Math.Between(20, config.width - 20);
const y = Phaser.Math.Between(40, config.height /2 );
let enemy = enemiesGroup.get(x, y);
enemy.setInteractive()
.on('pointerdown', () => {
// 1 in 5
if(Phaser.Math.Between(1, 5) === 5){
// Drop object
this.add.rectangle(enemy.x, enemy.y, 10, 10, 0xFFFF00);
}
enemy.destroy();
})
}
}
new Phaser.Game(config);
<script src="https://cdn.jsdelivr.net/npm/phaser#3.55.2/dist/phaser.js"></script>
Bonus (because I find this Phaser function especially useful):
If you want to select different loot/outcome in phaser you, could even let phaser select from a selected Array, with the function Phaser.Math.RNG.pick(...) (link to documentation)
Bonus Demo:
document.body.style = 'margin:0;';
var config = {
type: Phaser.AUTO,
width: 536,
height: 183,
scene: {
create
},
banner: false
};
function create () {
this.add.text(10, 10, 'Click to red Boxes')
let graphics = this.make.graphics({x: 0, y: 0, add: false});
graphics.fillStyle(0xFF0000);
graphics.fillRect(0, 0, 20, 20);
graphics.generateTexture('enemy', 20, 20)
let enemiesGroup = this.add.group({
defaultKey: 'enemy',
maxSize: 10
});
let maxEnemiesToShow = 10
for(let idx = 0; idx < maxEnemiesToShow; idx++){
const x = Phaser.Math.Between(20, config.width - 20);
const y = Phaser.Math.Between(40, config.height /2 );
let enemy = enemiesGroup.get(x, y);
let loot = [0x00ff00, 0xffff00, 0x0000ff, 0x0, 0x0];
enemy
.setInteractive()
.on('pointerdown', () => {
// Select Colro from an Array of possibilities
let color = Phaser.Math.RND.pick(loot);
// only drop item if color is not black
if(color > 0){
this.add.rectangle(enemy.x, enemy.y, 10, 10, color);
}
enemy.destroy();
})
}
}
new Phaser.Game(config);
<script src="https://cdn.jsdelivr.net/npm/phaser#3.55.2/dist/phaser.js"></script>
Phaser Random functions, have the added bonus that you can create your own RandomDataGenerator with a specific seed if you want, that the random numbers, that are created, are generated in the same sequence. Great for testing and so.
For a 1/5 chance, you can use JavaScript's Math.random.
Math.random() will return a float between 0 and 1.
To not hard code this, you can use a function like the following which will return true or false given an odds (in your case 1/5)
function rollRandom(odds) {
return Math.random() < odds;
}
console.log(rollRandom(1/5))
Followed the post The exactly same idea puts a rectangle along the centerline of it though cannot put an image in the right place, how do I fix it?, I tried to move the bolt along the line.
here is the code
let opposite_side = Math.abs(190 - 290);
let adjacent_side = Math.abs(290 - 90);
let adjacent_tartget = 123
let opposite_tartget = opposite_side / adjacent_side
opposite_tartget *= adjacent_tartget
this.tweens.add({
targets: bolt,
x: 290 - adjacent_tartget,
y: 190 + opposite_tartget,
rotation: angle,
ease: 'Linear',
duration: 1500,
onComplete: function(tween, targets) {
targets[0].setVisible(false);
}
});
and then I got what I want, a bolt moving along the line
to calculate the target x and y for tweens animation, I used SOHCAHTOA
I'd just like to know if Phaser 3 provides a handy tool to do the job.
An easy option is to make the image/sprite to physics-object and just move it, along the angle / direction.
Here the needed changes:
add physics to the game config:
...
physics: {default: 'arcade' },
...
calculate the direction as a Vector
let direction = new Phaser.Math.Vector2( 290 - 90, 190 - 290);
add physics to the image (and any object it should interact with)
this.physics.add.existing(bolt);
set the velocity of the physics body of the image
bolt.body.setVelocity(direction.x, direction.y );
Info: for this example you would not need to create a Vector2, but I like to use them, since they have some very convenient methods. like normalize, scale, length, and so on. So you don't have to do the math, just know the right function.
Here a working example:
Update: Bolt now hits target (second circle) and bolt is destroyed on impact.
var game = new Phaser.Game({
width: 600,
height: 180,
physics: {
default: 'arcade'
},
scene: {
preload: preload,
create: create
}
});
function preload() {
this.load.path = 'https://raw.githubusercontent.com/liyi93319/phaser3_rpg/main/part1/assets/';
this.load.atlas('bolt', 'bolt_atlas.png', 'bolt_atlas.json');
}
function create() {
let player = this.add.circle(90, 170, 10, 0xf00000);
let target = this.add.circle(490, 10, 10, 0xf00000);
let direction = new Phaser.Math.Vector2( target.x - player.x, target.y - player.y);
let angle = Phaser.Math.Angle.Between(player.x, player.y, target.x, target.y)
let reference = this.add.rectangle(player.x, player.y, 600, 5, 0x00f000).setOrigin(0, .5);
reference.rotation = angle
let bolt = this.add.sprite(player.x, player.y, 'bolt', 'bolt_strike_0002').setOrigin(0, .5);
bolt.rotation = angle;
this.physics.add.existing(bolt);
this.physics.add.existing(target);
bolt.body.setVelocity(direction.x, direction.y );
this.physics.add.collider(bolt, target, removeBolt );
}
function removeBolt(bolt, target){
bolt.destroy();
target.destroy();
}
<script src="https://cdn.jsdelivr.net/npm/phaser#3.55.2/dist/phaser.js"></script>
Extra Informtion: for more detailed examples on phaser physics, I recommend looking at these official examples: https://phaser.io/examples/v3/category/physics/arcade they cover most of the common needed function/use cases, and explain them very well. (Better then I ever could)
I am trying to do something like paint with KineticJS. I am trying to draw the color with circles that originate from the mouse position. However the eventlistener of the mouse position seems too slow and when I move the mouse too fast the circles drawn are far from each other resulting this:
I have seen people filling array with points drawing lines between them, but I thought thats very bad for optimization because after dubbing the screen too much the canvas starts lagging because it has too much lines that it redraws every frame. I decided to cancel the cleaning of the layer and I am adding new circle at the current mouse position and I remove the old one for optimization. However since Im not drawing lines on fast mouse movement it leaves huge gaps. I would be very grateful if anyone can help me with this.
Here is my code:
(function() {
var stage = new Kinetic.Stage({
container: 'main-drawing-window',
width: 920,
height: 750
}),
workplace = document.getElementById('main-drawing-window'),
layer = new Kinetic.Layer({
clearBeforeDraw: false
}),
border = new Kinetic.Rect({
stroke: "black",
strokeWidth: 2,
x: 0,
y: 0,
width: stage.getWidth(),
height: stage.getHeight()
}),
brush = new Kinetic.Circle({
radius: 20,
fill: 'red',
strokeWidth: 2,
x: 100,
y: 300
});
Input = function() {
this.mouseIsDown = false;
this.mouseX = 0;
this.mouseY = 0;
this.offsetX = 0;
this.offsetY = 0;
};
var input = new Input();
document.documentElement.onmousedown = function(ev) {
input.mouseIsDown = true;
};
document.documentElement.onmouseup = function(ev) {
input.mouseIsDown = false;
};
document.documentElement.onmousemove = function(ev) {
ev = ev || window.event;
// input.mouseX = (ev.clientX - workplace.offsetLeft);
// input.mouseY = (ev.clientY - workplace.offsetTop);
input.mouseX = (ev.offsetX);
input.mouseY = (ev.offsetY);
};
function DistanceBetweenPoints(x1, y1, x2, y2) {
return Math.sqrt(((x2 - x1) * (x2 - x1)) + ((y2 - y1) * (y2 - y1)));
}
var canvasDraw = setInterval(function() {
// console.log(input);
if (input.mouseIsDown) {
workplace.style.cursor = "crosshair";
var currentBrushPosition = brush.clone();
currentBrushPosition.setX(input.mouseX);
currentBrushPosition.setY(input.mouseY);
// var distance = DistanceBetweenPoints(brush.getX(), brush.getY(), currentBrushPosition.getX(), currentBrushPosition.getY());
// if (distance > brush.getRadius() * 2) {
// var fillingLine = new Kinetic.Line({
// points: [brush.getX(), brush.getY(), currentBrushPosition.getX(), currentBrushPosition.getY()],
// stroke: 'yellow',
// strokeWidth: brush.getRadius()*2,
// lineJoin: 'round'
// });
// // layer.add(fillingLine);
// }
layer.add(currentBrushPosition);
brush.remove();
brush = currentBrushPosition;
layer.draw();
// if (fillingLine) {
// fillingLine.remove();
// }
}
if (!input.mouseIsDown) {
workplace.style.cursor = 'default';
}
}, 16);
layer.add(border);
stage.add(layer);
})();
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Coloring Game</title>
<script src="https://cdnjs.cloudflare.com/ajax/libs/kineticjs/5.2.0/kinetic.min.js"></script>
</head>
<body>
<div id="main-drawing-window"></div>
<script type="text/javascript" src="./JS files/canvas-draw.js"></script>
</body>
</html>
Don't use individual Kinetic.Circles for each mousemove. Every Kinetic object is a "managed" object and that management takes up a lot of resources. KineticJS will slow to a crawl as the number of circles increases with every mousemove.
Instead, use a Kinetic.Shape and draw you circles onto the canvas with
// This is Pseudo-code since I haven't worked with KineticJS in a while
shapeContext.beginPath();
shapeContext.arc(mouseX,mouseY,20,0,Math.PI*2);
shapeContext.fillStrokeShape(this);
This will probably clear your problem, but if the mouse is moved very far in a single mousemove then you might have to draw a lineTo (instead of arc) between the last mouse point and the current far-away mouse point.
I'm trying to understand how to use PixiJS with the GSAP library TweeMax.
For that, I used to look some code into project using the two library, like this one :
http://www.shanemielke.com/archives/usopen-sessions/
But, I've some trouble to understand why I can't scale.
When I try to scale, my ball goes to the top left of my window [0, 0].
And When I specify scaleX and scaleY, there is nothing.
In the both cases, my animation continue without any mistake...
Here is my code
var renderer,
stage;
var init = function() {
// We create the canvas element
stage = new PIXI.Stage(0x202020);
renderer = new PIXI.CanvasRenderer(800, 600, null, false, true);
document.getElementById("loader").appendChild(renderer.view);
$(window).resize(onResize);
onResize();
requestAnimFrame(animate);
drawElements();
};
var onResize = function() {
renderer.resize(window.innerWidth, window.innerHeight);
}
var drawElements = function() {
var ball = new PIXI.Sprite.fromImage("./img/ball.png");
ball.position.x = (window.innerWidth / 2) - 5;
ball.position.y = -10;
ball.scaleX = ball.scaleY = 1;
stage.addChild(ball);
var t1 = new TimelineMax({onUpdate:animate, onUpdateScope:stage});
t1.to(ball, 1.5, {y: (window.innerHeight / 2), ease: Bounce.easeOut})
.to(ball, 2, {scaleX: 10})
.to(ball, 2, {alpha: 0});
}
var animate = function() {
requestAnimFrame(animate);
renderer.render(stage);
}
window.onload = function() {
init();
}
Cheers guys for help !
The scale property of a PIXI Sprite is a Point with x and y properties, so instead of:
ball.scaleX = ball.scaleY = 1;
You need to do:
ball.scale.x = ball.scale.y = 1;
When you tween the scale you need to pass TweenLite the scale object, instead of the sprite itself, like so:
tween.to(ball.scale, 2, {x: 10});