In looking to build a table seating/planning app. currently got a round table that i can dynamically add chairs around using code i found on stackoverflow. function is calculating the x,y absolut position of each seat around the table.
https://www.dropbox.com/s/4kvb0vre0dwtc0i/table.mov?dl=0
the video shows what i got so far.
for anyone interested the code for that is
export const calcRoundDimensions = (totalChairs, chairSize) => {
var chairspos = [];
var squareSize = chairSize * 2;
for (var i = 0; i < totalChairs; i++) {
var top = String(squareSize/2 + (-squareSize/2-chairSize) * Math.cos((360 / totalChairs / 180) * (i + 0) * Math.PI)) + 'px';
var left = String(squareSize/2 + (squareSize/2+chairSize) * (true ? Math.sin((360 / totalChairs / 180) * (i + 0) * Math.PI) : -Math.sin((360 / totalChairs / 180) * (i + 0) * Math.PI))) + 'px';
chairspos.push({top:top, left:left});
}
return {chairpos:chairspos, size:squareSize+chairSize};
}
I'm looking to do the same with a square one (also a rectangular one, but first thing's first).
square table would be fixed width (150px). I'm looking too be able to add chairs clockwise and have them centred on the side. (will have a 12 or 16 chair limit but this shouldn't matter i guess).
rectangle table would have one chair at either end then be able to add 5 or six chair on each of the longer ends.
searched the site but wasn't able to find much direction.
any help would be appreciated!
Not super clear on what you need but the following will get you positions of elements compared to the absolute top and left of the page:
const box = element.getBoundingClientRect();
const elementPosition = {
x:box.x+window.scrollX,
y:box.y+window.scrollY
};
Related
I've been trying different options to make an animated gradient page background but the performance of the page just sucks. It's causing a delay in my slide out JS menu and menu animations. I tried a JS version of the gradient, a CSS only version and still no luck. I tried this suggestion CSS performance relative to translateZ(0) and that didn't work either.
Are there any solutions to make an animated page background gradient that does not hurt the performance of the rest of the page? It's especially bad in Chrome and Safari but Firefox seems to handle it better.
Here is my testing site https://stacylauren-wp-stacymoorhead.c9users.io/ please excuse the lack of formatting, I'm just getting started on the layout. Here's my repo for the project https://github.com/stacymoorhead/portfolio-wordpress
This is what my javascript looks like that is applied to the body element as an ID:
var colors = new Array(
[252,238,33],
[217,224,33],
[140,198,63],
[0,176,176],
[147,39,143],
[212,20,90]);
var step = 0;
//color table indices for:
// current color left
// next color left
// current color right
// next color right
var colorIndices = [0,1,2,3];
//transition speed
var gradientSpeed = 0.002;
function updateGradient()
{
if ( $===undefined ) return;
var c0_0 = colors[colorIndices[0]];
var c0_1 = colors[colorIndices[1]];
var c1_0 = colors[colorIndices[2]];
var c1_1 = colors[colorIndices[3]];
var istep = 1 - step;
var r1 = Math.round(istep * c0_0[0] + step * c0_1[0]);
var g1 = Math.round(istep * c0_0[1] + step * c0_1[1]);
var b1 = Math.round(istep * c0_0[2] + step * c0_1[2]);
var color1 = "rgb("+r1+","+g1+","+b1+")";
var r2 = Math.round(istep * c1_0[0] + step * c1_1[0]);
var g2 = Math.round(istep * c1_0[1] + step * c1_1[1]);
var b2 = Math.round(istep * c1_0[2] + step * c1_1[2]);
var color2 = "rgb("+r2+","+g2+","+b2+")";
$('#gradient').css({
background: "-webkit-gradient(linear, left top, right bottom, from("+color1+"), to("+color2+"))"}).css({
background: "-moz-linear-gradient(left top, "+color1+" 0%, "+color2+" 100%)"});
step += gradientSpeed;
if ( step >= 1 )
{
step %= 1;
colorIndices[0] = colorIndices[1];
colorIndices[2] = colorIndices[3];
//pick two new target color indices
//do not pick the same as the current one
colorIndices[1] = ( colorIndices[1] + Math.floor( 1 + Math.random() * (colors.length - 1))) % colors.length;
colorIndices[3] = ( colorIndices[3] + Math.floor( 1 + Math.random() * (colors.length - 1))) % colors.length;
}
}
setInterval(updateGradient,10);
Is there even a solution? I am new to web development, and new to WordPress development so I'm just playing around on my portfolio to try and learn things.
I am having a go at building a game in html canvas. It's a Air Hockey game and I have got pretty far though it. There are three circles in the game, the disc which is hit and the two controllers(used to hit the disc/circle).
I've got the disc rebounding off the walls and have a function to detect when the disc has collided with a controller. The bit I am struggling with is when the two circle's collide, the controller should stay still and the disc should move away in the correct direction. I've read a bunch of article's but still can't get it right.
Here's a Codepen link my progress so far. You can see that the puck rebounds off the controller but not in the correct direction. You'll also see if the puck comes from behind the controller it goes through it.
http://codepen.io/allanpope/pen/a01ddb29cbdecef58197c2e829993284?editors=001
I think what I am after is elastic collision but not sure on how to work it out. I've found this article but have been unable to get it working.
http://gamedevelopment.tutsplus.com/tutorials/when-worlds-collide-simulating-circle-circle-collisions--gamedev-769
Heres is my collision detection function. Self refer's to the disc and the controller[i] is the controller the disc hits.
this.discCollision = function() {
for (var i = 0; i < controllers.length; i++) {
// Minus the x pos of one disc from the x pos of the other disc
var distanceX = self.x - controllers[i].x,
// Minus the y pos of one disc from the y pos of the other disc
distanceY = self.y - controllers[i].y,
// Multiply each of the distances by itself
// Squareroot that number, which gives you the distance between the two disc's
distance = Math.sqrt(distanceX * distanceX + distanceY * distanceY),
// Added the two disc radius together
addedRadius = self.radius + controllers[i].radius;
// Check to see if the distance between the two circles is smaller than the added radius
// If it is then we know the circles are overlapping
if (distance <= addedRadius) {
var newVelocityX = (self.velocityX * (self.mass - controllers[i].mass) + (2 * controllers[i].mass * controllers[i].velocityX)) / (self.mass + controllers[i].mass);
var newVelocityY = (self.velocityY * (self.mass - controllers[i].mass) + (2 * controllers[i].mass * controllers[i].velocityX)) / (self.mass + controllers[i].mass);
self.velocityX = newVelocityX;
self.velocityY = newVelocityY;
self.x = self.x + newVelocityX;
self.y = self.y + newVelocityY;
}
}
}
Updated
Deconstructed a circle collision demo & tried to implement their collision formula. This is it below, works for hitting the puck/disc forward & down but wont hit the back backwards or up for some reason.
this.discCollision = function() {
for (var i = 0; i < controllers.length; i++) {
// Minus the x pos of one disc from the x pos of the other disc
var distanceX = self.x - controllers[i].x,
// Minus the y pos of one disc from the y pos of the other disc
distanceY = self.y - controllers[i].y,
// Multiply each of the distances by itself
// Squareroot that number, which gives you the distance between the two disc's
distance = Math.sqrt(distanceX * distanceX + distanceY * distanceY),
// Added the two disc radius together
addedRadius = self.radius + controllers[i].radius;
// Check to see if the distance between the two circles is smaller than the added radius
// If it is then we know the circles are overlapping
if (distance < addedRadius) {
var normalX = distanceX / distance,
normalY = distanceY / distance,
midpointX = (controllers[i].x + self.x) / 2,
midpointY = (controllers[i].y + self.y) / 2,
delta = ((controllers[i].velocityX - self.velocityX) * normalX) + ((controllers[i].velocityY - self.velocityY) * normalY),
deltaX = delta*normalX,
deltaY = delta*normalY;
// Rebound puck
self.x = midpointX + normalX * self.radius;
self.y = midpointY + normalY * self.radius;
self.velocityX += deltaX;
self.velocityY += deltaY;
// Accelerate once hit
self.accelerationX = 3;
self.accelerationY = 3;
}
}
}
I'm not great at these types of math problems, but it looks like you need to rotate your vectors around sine and cosine angles. I will point you at a working example and the source code that drives it. I did not derive this example.
I solved just the circle collision detection part of this problem recently, but one solution I came across includes code for establishing new vector directions. Ira Greenburg hosts his original source at processing.org. Ira further cites Keith Peter's Solution in Foundation Actionscript Animation: Making Things Move!
I copied Ira's code into Processing's Javascript mode then pushed it to Github Pages so you can see it before you try it.
The main issue with my code was the user controller was attached to the mouse. When a collision would happen, the function would run constantly because the circles where still touching due to the mouse position. I changed my code so the controller is controlled by the users keyboard.
I also asked for help on reddit & got some help with my collision code. Some good resources where linked.
(http://www.reddit.com/r/javascript/comments/3cjivi/having_a_go_at_building_an_air_hockey_game_stuck/)
Preamble: there's an issue logged with the Google Maps API, requesting the ability to correct the roll angle of street view tiles to compensate for hills. I've come up with a client-side workaround involving some css sorcery on the tile container. Here's my rotate function:
rotate: function() {
var tilesLoaded = setInterval(function() {
var tiles = $('map-canvas').getElementsByTagName('img');
for (var i=0; i<tiles.length; i++) {
if (tiles[i].src.indexOf(maps.panorama.getPano()) > -1) {
if (typeof maps.panorama.getPhotographerPov != 'undefined') {
var pov = maps.panorama.getPhotographerPov(),
pitch = pov.pitch,
cameraHeading = pov.heading;
/**************************
// I need help with my logic here.
**************************/
var yaw = pov.heading - 90;
if (yaw < 0) yaw += 360;
var scale = ((Math.abs(maps.heading - yaw) / 90) - 1) * -1;
pitch = pov.pitch * scale;
tiles[i].parentNode.parentNode.style.transform = 'rotate(' + pitch + 'deg)';
clearInterval(tilesLoaded);
return;
}
}
}
}, 20);
}
A full (and more thoroughly commented) proof-of-concept is at this JSFiddle. Oddly, the horizon is just about perfectly level if I do no calculation at all on the example in the JSFiddle, but that result isn't consistent for every Lat/Lng. That's just a coincidence.
So, I need to calculate the roll at the client's heading, given the client heading, photographer's heading, and photographer's pitch. Assume the photographer is either facing uphill or downhill, and pov.pitch is superlative (at the min or max limit). How can I calculate the desired pitch facing the side at a certain degree?
Edit: I found an equation that seems to work pretty well. I updated the code and the fiddle. While it seems to be pretty close to the answer, my algorithm is linear. I believe the correct equation should be logarithmic, resulting in subtler adjustments closer to the camera heading and opposite, while to the camera's left and right adjustments are larger.
I found the answer I was looking for. The calculation involves spherical trigonometry, which I didn't even know existed before researching this issue. If anyone notices any problems, please comment. Or if you have a better solution than the one I found, feel free to add your answer and I'll probably accept it if it's more reliable or significantly more efficient than my own.
Anyway, if the tile canvas is a sphere, 0 pitch (horizon) is a plane, and camera pitch is another plane intersecting at the photographer, the two planes project a spherical lune onto the canvas. This lune can be used to calculate a spherical triangle where:
polar angle = Math.abs(camera pitch)
base = camera heading - client heading
one angle = 90° (for flat horizon)
With two angles and a side available, other properties of a spherical triangle can be calculated using the spherical law of sines. The entire triangle isn't needed -- only the side opposite the polar angle. Because this is math beyond my skills, I had to borrow the logic from this spherical triangle calculator. Special thanks to emfril!
The jsfiddle has been updated. My production roll getter has been updated as follows:
function $(what) { return document.getElementById(what); }
var maps = {
get roll() {
function acos(what) {
return (Math.abs(Math.abs(what) - 1) < 0.0000000001)
? Math.round(Math.acos(what)) : Math.acos(what);
}
function sin(what) { return Math.sin(what); }
function cos(what) { return Math.cos(what); }
function abs(what) { return Math.abs(what); }
function deg2rad(what) { return what * Math.PI / 180; }
function rad2deg(what) { return what * 180 / Math.PI; }
var roll=0;
if (typeof maps.panorama.getPhotographerPov() != 'undefined') {
var pov = maps.panorama.getPhotographerPov(),
clientHeading = maps.panorama.getPov().heading;
while (clientHeading < 0) clientHeading += 360;
while (clientHeading > 360) clientHeading -= 360;
// Spherical trigonometry method
a1 = deg2rad(abs(pov.pitch));
a2 = deg2rad(90);
yaw = deg2rad((pov.heading < 0 ? pov.heading + 360 : pov.heading) - clientHeading);
b1 = acos((cos(a1) * cos(a2)) + (sin(a1) * sin(a2) * cos(yaw)));
if (sin(a1) * sin(a2) * sin(b1) !== 0) {
roll = acos((cos(a1) - (cos(a2) * cos(b1))) / (sin(a2) * sin(b1)));
direction = pov.heading - clientHeading;
if (direction < 0) direction += 360;
if (pov.pitch < 0)
roll = (direction < 180) ? rad2deg(roll) * -1 : rad2deg(roll);
else
roll = (direction > 180) ? rad2deg(roll) * -1 : rad2deg(roll);
} else {
// Fall back to algebraic estimate to avoid divide-by-zero
var yaw = pov.heading - 90;
if (yaw < 0) yaw += 360;
var scale = ((abs(clientHeading - yaw) / 90) - 1) * -1;
roll = pov.pitch * scale;
if (abs(roll) > abs(pov.pitch)) {
var diff = (abs(roll) - abs(pov.pitch)) * 2;
roll = (roll < 0) ? roll + diff : roll - diff;
}
}
}
return roll;
}, // end maps.roll getter
// ... rest of maps object...
} // end maps{}
After rotating the panorama tile container, the container also needs to be expanded to hide the blank corners. I was originally using the 2D law of sines for this, but I found a more efficient shortcut. Thanks Mr. Tan!
function deg2rad(what) { return what * Math.PI / 180; }
function cos(what) { return Math.cos(deg2rad(what)); }
function sin(what) { return Math.sin(deg2rad(what)); }
var W = $('map-canvas').clientWidth,
H = $('map-canvas').clientHeight,
Rot = Math.abs(maps.originPitch);
// pixels per side
maps.growX = Math.round(((W * cos(Rot) + H * cos(90 - Rot)) - W) / 2);
maps.growY = Math.round(((W * sin(Rot) + H * sin(90 - Rot)) - H) / 2);
There will be no more edits to this answer, as I don't wish to have it converted to a community wiki answer yet. As updates occur to me, they will be applied to the fiddle.
EDIT: So apparently, PI is finite in JavaScript (which makes sense). But that leaves me with a major problem. What's the next best way to calculate the angles I need?
Alright, first, my code:
http://jsfiddle.net/joshlalonde/vtfyj/34/
I'm drawing cubes that open up to a 120 degree angle.
So the coordinates are calculated based on (h)eight and theta (120).
On line 46, I have a for loop that contains a nested for loop used for creating rows/columns.
It's somewhat subtle, but I noticed that the lines aren't matching up exactly. The code for figuring out each cubes position is on line 49. One of the things in the first parameter (my x value) for the origin of the cube is off. Can anyone help figure out what it is?
var cube = new Cube(
origin.x + (j * -w * (Math.PI)) +
(i * w * (Math.PI))
, origin.y + j * (h / 2) +
i * (h / 2) +
(-k*h), h);
Sorry if that's confusing. I,j, and k refer to the variable being incremented by the for loops. So basically, a three dimensional for loop.
I think the problem lies with Math.PI.
The width isn't the problem, or so I believe. I originally used 3.2 (which I somehow guessed and it seemed to line up pretty good. But I have no clue what the magical number is). I'm guessing it has to do with the angle being converted to Radians, but I don't understand why Math.PI/180 isn't the solution. I tried multiple things. 60 (in degrees) * Math.PI/180 doesn't work. What is it for?
EDIT: It might just be a JavaScript related math problem. The math is theoretically correct but can't be calculated correctly. I'll accept the imperfection to spare myself from re-writing code in unorthodox manners. I can tell it would take a lot to circumvent using trig math.
There are 2 problems...
Change line 35 to var w=h*Math.sin(30);. The 30 here matches the this.theta / 4 in the Cube getWidthmethod since this.theta equals 120.
Use the following code to generate the position of your new cube. You don't need Math.Pi. You needed to use both the cube width and height in your calculation.
var cube = new Cube(
origin.x+ -j*w - i*h,
origin.y + -j*w/2 + i*h/2,
h);
Alright I found the solution!
It's really simple - I was using degrees instead of radians.
function Cube(x, y, h) {
this.x = x
this.y = y
this.h = h;
this.theta = 120*Math.PI/180;
this.getWidth = function () {
return (this.h * Math.sin(this.theta / 2));
};
this.width = this.getWidth();
this.getCorner = function () {
return (this.h / 2);
};
this.corner = this.getCorner();
}
So apparently Javascript trig functions use Radians, so that's one problem.
Next fix I made was to the offset of each point in the cube. It doesn't need one! (o.O idk why. But whatever it works. I left the old code just in case I discover why later on).
function draw() {
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
ctx.fillStyle = "#000";
ctx.fillRect(0, 0, canvas.width, canvas.height); // Draw a black canvas
var h = 32;
var width = Math.sin(60*Math.PI/180);
var w = h*width;
var row = 9; // column and row will always be same (to make cube)
var column = row;
var area = row * column;
var height = 1;
row--;
column--;
height--;
var origin = {
x: canvas.width / 2,
y: (canvas.height / 2) - (h * column/2) + height*h
};
var offset = Math.sqrt(3)/2;
offset = 1;
for (var i = 0; i <= row; i++) {
for (var j = 0; j <= column; j++) {
for (var k = 0; k <= height; k++) {
var cube = new Cube(
origin.x + (j * -w * offset) +
(i * w * offset)
, origin.y + (j * (h / 2) * offset) +
(i * (h / 2) * offset) +
(-k*h*offset), h);
var cubes = {};
cubes[i+j+k] = cube; // Store to array
if (j == column) {
drawCube(2, cube);
}
if (i == row) {
drawCube(1, cube);
}
if (k == height) {
drawCube(0,cube);
}
}
}
}
}
See the full Jsfiddle here: http://jsfiddle.net/joshlalonde/vtfyj/41/
I'm looking for someone to help guide me in the right direction for a function I'm trying to create.
I need to create an arrow that when at a certain point of degree, a tree grows, I have created 7 different heights and 7 different images for the tree's for a clean look.
Basically you know how you can have an image and rotate it using
<script type="text/javascript">
var img = $('.image');
if(img.length > 0){
var offset = img.offset();
function mouse(evt){
var center_x = (offset.left) + (img.width()/2);
var center_y = (offset.top) + (img.height()/2);
var mouse_x = evt.pageX; var mouse_y = evt.pageY;
var radians = Math.atan2(mouse_x - center_x, mouse_y - center_y);
var degree = (radians * (180 / Math.PI) * -1) + 90;
img.css('-moz-transform', 'rotate('+degree+'deg)');
img.css('-webkit-transform', 'rotate('+degree+'deg)');
img.css('-o-transform', 'rotate('+degree+'deg)');
img.css('-ms-transform', 'rotate('+degree+'deg)');
}
$(document).mousemove(mouse);
}
</script>
But how do I get my arrow to stop at 20 degree's, 25 degree's, 30 degree's etc etc.. while at the same time loading the new image i have assigned to that certain degree (whatever the tip of the arrow is pointed at) all doing this by hover over.
And not only do stop and load the new image, but also once the user clicks submit it adds data to my tree table within my db. So basically, its an arrow, the tip of the arrow gets set at a certain degree, loads the new image, takes the height of the image (i need some way of assigning the height var to each individual image im guessing?) then query that into my tree table under the tree height field.
Any help, links to get me started would be greatly appreciated.
Also, is there a way to do this with Canvas or SVG? Instead of using a arrow image as my arrow? For a more clean look.
Here is an example of how you might render an arrow following the mouse using canvas.
http://jsbin.com/inufoy/edit
Locking the rotation of the arrow to certain points is as simple as filtering the parameter on the draw function. eg:
var segs = 7;
var coefficient = Math.PI / segs;
r -= ((r + coefficient) % (coefficient * 2)) - coefficient;
From there all you have to do is assign each image a rotation, and check when the arrow is pointing towards the tree, then load the tree's image.
Edit:
Here's another version of that script with a static arrow base such as your description:
http://jsbin.com/inufoy/5/edit