Unable to produce multiply objects in javascript after eachother - javascript

I am attempting to make a simple version of flappy bird to help me learn JavaScript. I am using p5.js. I have made a constructor function for the walls that move across the screen, here is the code:
function Wall() {
this.xw = width- 20;
this.width = 20;
this.len = Math.floor(Math.random() * 200) + 50
this.rects = function() {
rect(this.xw,0,this.width,this.len);
translate(0,height);
rect(this.xw,0,this.width,-height + 70 + this.len);
}
this.update = function(){
this .xw -= 1;
}
}
I want these objects to move across the screen after eachother
I used this code to attempt to do this. However my problem is that it is only producing one wall.
if(frameCount % 40 == 0) {
walls.push(new Wall());
}
for(i = 0; i < walls.length; i++){
walls[i].rects();
walls[i].update();
}
I have also created an empty array and in the setup function I have written:
var walls = [];
walls.push(new Wall());
Any help is much appreciated.

It's been a while, but if you're still stuck here, I noticed something.
It looks like your function is fine, but you've got a little typo. An extra space is preventing this.xw from decrementing when the update method is called (this .xw instead of this.xw).
You can confirm in your console by typing walls.length and watching each wall get added to the array. But then they're all stacked on top (z-axis) of each other with the same position because each wall's xw attribute isn't changing.
For clarity, here's the change:
function Wall() {
this.xw = width- 20;
this.width = 20;
this.len = Math.floor(Math.random() * 200) + 50
this.rects = function() {
rect(this.xw,0,this.width,this.len);
translate(0,height);
rect(this.xw,0,this.width,-height + 70 + this.len);
}
this.update = function(){
this.xw -= 1; // <-- this line here, remove the space
}
}

Related

Natural Movement with Noise

Im creating an object that randomly moves in a natural way using noise like this (works as intended):
The objects encounter a collision and their trajectory is manipulated, the movement path now changes to straight line (words as intended)
thisRabbit.x = _world.width * (noise(thisRabbit.t));
thisRabbit.y = _world.height * (noise(thisRabbit.t+5));
thisRabbit.t += 0.001;
The problem is after this movement , i want the object to start moving in a random direction again as it was initially. If i use the same function, the object jumps to the last location before the trajectory was modified.
let vx = this.acquiredFood[0] - this.x;
let vy = this.acquiredFood[1] - this.y;
let f = (this.genes.speed + 10) / Math.sqrt(vx*vx+vy*vy);
vx = vx * f;
vy = vy * f;
let newX = this.x + vx;
let newY = this.y + vy;
So how do i get the object to move as before, given a starting position
edit: snippet here: https://editor.p5js.org/vince.chinner/sketches/HPFKR8eIw
Your problem is that you used a factor from 0 to 1 generated with noise and an incremented seed to generate the position by multiplying directly the world dimentions. When reaching food, you cannot increment the seed as to be in the exact position where the movement to get your food led you (I found no inverse function for noise to get the seed from the return value).
What you need to do instead is use the noise to increment or decrement the coordinates, so that no matter where the seed is, you don't loose your current position.
Here are the different corrections I applied to the code, as there were also syntax errors, I can't really paste the whole stuff here for copyright reasons (you didn't share the whole code here and the sketch belongs to you)
MAIN CORRECTION:
used a var found because returning from the forEach callback doesn't make you leave the findFood function, but the callback one. And the forEach loop doesn't stop. Using this var prevents the further forEach tests to be made and allows you to return from findFood so that no further move is made after seeing food.
noise is now applied to a value of 4 and I subtract 2, so that x and y now change with a range of -2 to 2 each. Of course, with this method, you need to check against world dimentions or else the rabbit could leave the world. The seed increment has been changed too or else it would vary too slowly (adapt values as you wish)
findFood(){
var thisRabbit = this, found = false;
_world.food.forEach(f => {
if(!found){
let d = int(dist(f[0], f[1], thisRabbit.x, thisRabbit.y));
if(d < (thisRabbit.genes.vision / 2)+3){
thisRabbit.state = "foundFood";
this.acquiredFood = f;
found = true;
}
}
});
if(found){ return; }
thisRabbit.x += (noise(thisRabbit.t) * 4) - 2;
if(thisRabbit.x < 0){ thisRabbit.x = 0; }
if(thisRabbit.x > _world.width){ thisRabbit.x = _world.width; }
thisRabbit.y += (noise(thisRabbit.t + 5) * 4) - 2;
if(thisRabbit.y < 0){ thisRabbit.y = 0; }
if(thisRabbit.y > _world.height){ thisRabbit.y = _world.height; }
thisRabbit.t += 0.01;
}
SYNTAX ERRORS:
lines 23 / 24: assignment should be with a value (null or false)
this.genes = null;
this.acquiredFood = null;
lines 129 to 133: end you instructions with a ; instead of a ,
this.width = w;
this.height = h;
this.foodDensity = foodDensity;
this.food = [];
this.rabits = [];
line 156 to 160: there should be no space between rabbit and .t. Additionnally, because the coordinates are not directly linked to t, I would prefer to use random for starting position:
let x = this.width * random();
let y = this.height * random();
let _rabbit = new rabbit(x, y);
_rabbit.genes = genes;
_rabbit.t = t;

Canvas animation with JavaScript. Random coordinates and speed at every initiation

Edited : Thanks to all for valuable time and effort. Finally I made this )) JSfiddle
I was just playing with canvas and made this. Fiddle link here.
... some code here ...
var cords = [];
for(var i = 50; i <= width; i += 100) {
for(var j = 50; j <= height; j += 100) {
cords.push({ cor: i+','+j});
}
}
console.log(cords);
var offset = 15,
speed = 0.01,
angle = 0.01;
cords.forEach(function(e1) {
e1.base = parseInt(Math.random()*25);
e1.rgb = 'rgb('+parseInt(Math.random()*255)+','+parseInt(Math.random()*255)+','+parseInt(Math.random()*255)+')';
});
setInterval(function() {
cords.forEach(function(e1) {
e1.base = parseInt(Math.random()*25);
e1.rgb = 'rgb('+parseInt(Math.random()*255)+','+parseInt(Math.random()*255)+','+parseInt(Math.random()*255)+')';
});
},5000);
function render() {
ctx.clearRect(0,0,width,height);
cords.forEach(function(e1) {
//console.log(e1);
ctx.fillStyle = e1.rgb;
ctx.beginPath();
var r = e1.base + Math.abs(Math.sin(angle)) * offset;
var v = e1.cor.split(',');
ctx.arc(v[0],v[1],r,0,Math.PI * 2, false);
ctx.fill();
});
angle += speed;
requestAnimationFrame(render);
}
render();
Was wondering if -
Coordinates can be made random, now they are fixed as you can see. After 5000 mil, balls will show up in various random cords but even at their fullest they won't touch each other.
Every ball has same speed for changing size, I want that to be different too. Meaning, After 5000 mil, they show up with different animation speeds as well.
Also any suggestion on improving code and making it better/quicker/lighter is much appreciated. Thank you !
TL;DR - See it running here.
Making the coordinates random:
This requires you to add some random displacement to the x and y coordinates. So I added a random value to the coordinates. But then a displacement of less than 1 is not noticeable. So you'd need to magnify that random number by a multiplier. That's where the randomizationFactor comes in. I have set it to 100 since that is the value by which you shift the coordinates in each iteration. So that gives a truly random look to the animation.
Making Speed Random:
This one took me a while to figure out, but the ideal way is to push a value of speed into the array of coordinates. This let's you ensure that for the duration of animation, the speed will remain constant and that gives you a smoother feel. But again multiplying the radius r with a value between 0 and 1 reduces the speed significantly for some of the circles. So I have added a multiplier to 3 to compensate slightly for that.
Ideally I'd put a 2, as the average value of Math.random() is 0.5, so a multiplier of 2 would be adequate to compensate for that. But a little experimentation showed that the multiplier of 3 was much better. You can choose the value as per your preference.
Your logic of generating the coordinates changes as follows:
for(var i = 50; i <= width;i += 100) {
for(var j = 51; j <= height;j += 100) {
var x = i + (Math.random() - 0.5)*randomizationFactor;
var y = j + (Math.random() - 0.5)*randomizationFactor;
cords.push({ cor: x+','+y, speed: Math.random()});
}
}
Your logic of enlarging the circles changes as follows:
function render() {
ctx.clearRect(0,0,width,height);
cords.forEach(function(e1) {
//console.log(e1);
ctx.fillStyle = e1.rgb;
ctx.beginPath();
var r = e1.base + Math.abs(Math.sin(angle)) * offset * e1.speed * 3;
var v = e1.cor.split(',');
ctx.arc(v[0],v[1],r,0,Math.PI * 2, false);
ctx.fill();
});
angle += speed ;
requestAnimationFrame(render);
}
Suggestion: Update the coordinates with color
I'd probably also update the location of circles every 5 seconds along with the colors. It's pretty simple to do as well. Here I've just created a function resetCoordinates that runs every 5 seconds along with the setBaseRgb function.
var cords = [];
function resetCoordinates() {
cords = [];
for(var i = 50; i <= width;i += 100) {
for(var j = 51; j <= height;j += 100) {
var x = i + (Math.random() - 0.5)*randomizationFactor;
var y = j + (Math.random() - 0.5)*randomizationFactor;
cords.push({ cor: x+','+y, speed: Math.random()});
}
}
}
UPDATE I did some fixes in your code that can make your animation more dynamic. Totally rewritten sample.
(sorry for variable name changing, imo now better)
Built in Math.random not really random, and becomes obvious when you meet animations. Try to use this random-js lib.
var randEngine = Random.engines.mt19937().autoSeed();
var rand = function(from, to){
return Random.integer(from, to)(randEngine)
}
Internal base properties to each circle would be better(more dynamic).
var circles = [];
// better to save coords as object neither as string
for(var i = 50; i <= width; i += 100)
for(var j = 50; j <= height; j += 100)
circles.push({
coords: {x:i,y:j}
});
We can adjust animation with new bouncing property.
var offset = 15,
speed = 0.005,
angle = 0.01,
bouncing = 25;
This is how setBaseRgb function may look like
function setBaseRgb(el){
el.base = rand(-bouncing, bouncing);
el.speed = rand(5, 10) * speed;
el.angle = 0;
el.rgb = 'rgb('+rand(0, 255)+','+rand(0, 255)+','+rand(0, 255)+')';
}
All your animations had fixed setInterval timeout. Better with random timeout.
cords.forEach(function(el){
// random timeout for each circle
setInterval(setBaseRgb.bind(null,el), rand(3000, 5000));
})
You forgot to add your base to your circle position
function render() {
ctx.clearRect(0,0,width,height);
circles.forEach(function(el) {
ctx.fillStyle = el.rgb;
ctx.beginPath();
var r = bouncing + el.base + Math.abs(Math.sin(el.angle)) * offset;
var coords = el.coords;
ctx.arc(
coords.x + el.base,
coords.y + el.base,
r, 0, Math.PI * 2, false
);
ctx.fill();
el.angle += el.speed;
});
requestAnimationFrame(render);
}
render();
Effect 1 JSFiddle
Adding this
if(el.angle > 1)
el.angle=0;
Results bubling effect
Effect 2 JSFiddle
Playing with formulas results this
Effect 3 JSFiddle

Javascript onclick event on newly created elements

I've got several functions all linked so it will ...
create new elements and set their properties and stuff
once elements are in place they should trigger function.
And they do! Kind of...
More like they trigger half of a function that's attached to them upon creation. The part where they onclick trigger a function that starts a loading on my progress bar (which is their purpose) is alright. But the much simpler part, where they hide after click, doesn't.
As the code is quite complex I'll place here larger part of it, so don't panic. Problem might be somewhere else then I expect. Here it is...
// defines function for checkpoint
function checkpointed() {
this.style.display = 'none'; // !here dwells the douch part!
if (toLoad < 100) {
toLoad += 100/$(this).attr('numButs');
var sim = setInterval(progressSim, 50);
}
// defining creation of checkpoints
function checkpoints(num) {
var angle = 4.72,
step = (2 * Math.PI) / num;
for (i = 1; i < num + 1; i++) {
var x = $('#progressBar').width()/2 + radius * Math.cos(angle) ;
var y = $('#progressBar').height()/2 + radius * Math.sin(angle);
angle += step;
var newContent = document.createElement('IMG');
var newCheckpoint = document.createElement('SPAN');
var numButs = document.createAttribute('numButs');
numButs.value = num;
var Class = document.createAttribute('class');
Class.value = 'checkpoint';
var img = document.createAttribute('src');
img.value = 'img/lock.png';
newContent.setAttributeNode(img);
newCheckpoint.setAttributeNode(numButs);
newCheckpoint.setAttributeNode(Class);
$(newCheckpoint).append(newContent);
$('.projectBar').append(newCheckpoint);
x -= 24;
y -= 24;
$(newCheckpoint).offset({top:y, left: x});
newCheckpoint.onclick = checkpointed;
};
};
// creates checkpoints upon clicking on create button
document.getElementById('create').onclick = function(){
checkpoints(document.getElementById('numCheckpoint').value);
$(this).hide();
$('#numCheckpoint').hide();
};
I should probably sum up what is this all about.
I have circular progressBar that measures progression of users project. User says "Hey, my project has like 5 steps (or 20 idc)" and "create" button will make 5 checkpoints placed on the progressBar evenly. By clicking on checkpoints you load the progress bar by 20% per clicked checkpoint.
Don't worry though, I've already figured out the code for loading and the geometrics.
However I'm bit stuck here... on simple onclick functions. Please if you have an idea try achieve it with plain JavaScript or jQuery (trying to do this without other frameworks, libraries or plugins).
EDIT: Just found out that checkpoint are set alright, as they really hide after clicking. Problem is in creation of checkpoints as the loop creates about 15 more checkpoints stacked one on another. So you have to click each of them to hide them all... So problem is in the loop.
EDIT2: Figured it out. The loop for (i = 1; i < num + 1; i++) had the numparameter as a String coming from input field. So simple parseInt() did the trick.
The mixed Jquery and plain Javascript is messing with my head... Any way how about when you create a new element, give it some sort of class. Instead of giving setting onclick, use jQuery's on selector to bind click events to those dynamic elements. Try The Following:
$(document).on("click", ".Checkpoint", function(event) {
$(event.target).hide();
if (toLoad < 100) {
toLoad += 100 / $(this).attr('numButs');
var sim = setInterval(progressSim, 50);
}
});
// defining creation of checkpoints
function checkpoints(num) {
var angle = 4.72,
step = (2 * Math.PI) / num;
for (i = 1; i < num + 1; i++) {
var x = $('#progressBar').width() / 2 + radius * Math.cos(angle);
var y = $('#progressBar').height() / 2 + radius * Math.sin(angle);
angle += step;
var newContent = $('<img></img>');
var newCheckpoint = $('<span></span>');
$("body").append(newCheckpoint);
newContent.attr("numButs", num);
newContent.attr("src", 'img/lock.png');
newContent.addClass("Checkpoint");
$(newCheckpoint).append(newContent);
$('.projectBar').append(newCheckpoint);
x -= 24;
y -= 24;
$(newCheckpoint).offset({
top: y,
left: x
});
}
}
// creates checkpoints upon clicking on create button
$(document).on("click","#create",function(e) {
checkpoints($('#numCheckpoint').val());
$(e.target).hide();
$('#numCheckpoint').hide();
});
Changed stuff to work more in jQuery, hope you don't mind...

CSS FPS view flickering and freezing

I'm trying to make a basic FPS view using CSS.
Here's a demo of what I have so far: https://jsfiddle.net/w8q7xtmL/
In particular, movement is as simple as detecting keypresses, then:
// "self" is if the player object
requestAnimationFrame(step);
function step() {
if( keys[37]) self.direction += 2;
if( keys[39]) self.direction -= 2;
if( keys[38]) {
self.x += Math.cos(self.direction/180*Math.PI) * 4;
self.y -= Math.sin(self.direction/180*Math.PI) * 4;
}
if( keys[40]) {
self.x -= Math.cos(self.direction/180*Math.PI) * 4;
self.y += Math.sin(self.direction/180*Math.PI) * 4;
}
self.camera.style.transform = "rotateX(90deg) rotateZ("+(self.direction-90)+"deg) translate(-"+self.x+"px,-"+self.y+"px)";
requestAnimationFrame(step);
}
This works quite well, but there are a couple of issues.
Sometimes, elements don't stack correctly. The floor will be visible when walls should be blocking it from view, for instance.
Other times, the view will freeze completely, despite there being no errors in the console or anything that would indicate failure. It just... stops. Sometimes I can get it un-stuck by trying to move around a bit to "unstick" it, but other times I just have to reload the page.
Are there any discernible errors in my approach, or is the state of 3D transforms just not there yet for this kind of thing?
For the record, in case it matters, I'm developing with Google Chrome 49.
I can't believe I missed this.
Before:
self.camera.style.transform = "rotateX(90deg) rotateZ("+(self.direction-90)+"deg)
translate(-"+self.x+"px,-"+self.y+"px)";
After:
self.camera.style.transform = "rotateX(90deg) rotateZ("+(self.direction-90)+"deg)
translate("+(-self.x)+"px,"+(-self.y)+"px)";
Because, funnily enough, when self.x is negative, you get translate(--12px,0px) which is invalid.
I believe it is because you are detecting keys in a loop.
Instead, use this:
var rotval = 0;
window.addEventListener('keydown', function(e) {
key = e.keyCode
if(key === "left")
{
rotval = 1;
}
}, true);
window.addEventListener('keyup', function(e) {
key = e.keyCode
if(key === "left")
{
rotval = 0;
}
}, true);
then just add a variable to the loop function and when it is more or less than 0, it moves or rotates the camera!
function loop()
{
camera.rotation.y += rotval
camera.position.x //and so on
}
setInterval(loop,30)
Hope this helps :)

html5 canvas object collisions and physics

I'm working on a simple html5 platformer, building of a previous game but having trouble with collisions and physics. below is a sample of code regarding the floor and how it handles collisions. the full code is here. http://www.ambitiongames.co.uk/dev/game.php with the game being here http://www.ambitiongames.co.uk/dev/
the problem I'm having is the collisions are based on events grabbing which sometimes leaves the player in the floor not on it.
also, due to the way jumping and falling work there's no gravity, meaning a player can simply jump on a higher ledge and then walk off into the air.
whats the a good way to set up a permanent state of gravity ?
whats a good way to interact / collide with the floor or other objects ?
that.draw = function(){
try {
ctx.drawImage(that.image, that.x, that.y, that.width, that.height);
} catch (e) {
}
}
return that;
};
var nrOffloors = 40,
floors = [],
floorWidth = 20,
floorHeight = 40;
var generatefloor = function(){
for (var i = 0; i < 10; i++) {
floors[i] = new Floor(i * 20,280);
}
for (var i = 10; i < 12; i++) {
floors[i] = new Floor(i * 20,260);
}
}();
var checkCollisionfloor = function(){
floors.forEach(function(e, ind){
if (
(player.X < e.x + floorWidth) &&
(player.X + player.width > e.x) &&
(player.Y + player.height > e.y) &&
(player.Y + player.height < e.y + floorHeight)
) {
e.onCollide();
}
});
}
You can try a library like Box2D.js. It handles everything from collision detection to gravity.
Check out it's demos.

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