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gugu

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This commit is contained in:
Robert 2021-03-10 16:09:44 +01:00
parent a8db77efb3
commit 99d494eef1
1 changed files with 52 additions and 29 deletions
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81
pendulum/main.js
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@ -12,17 +12,38 @@ let centerMass;
let inertia;
let L;
let g = 4.81;
let g = 9.81;
let acc = 0;
let vel = 0;
let theta = 0;
let canvasSize = 2; // 2 meters, whatever
function screenToWorld(point)
{
returnVal = createVector(point.x, point.y);
returnVal.div(width);
returnVal.mult(canvasSize);
return returnVal;
}
function worldToScreen(point)
{
returnVal = createVector(point.x, point.y);
returnVal.div(canvasSize);
returnVal.mult(width);
return returnVal;
}
function insideShape(point)
{
if(!shapeComplete)
return false;
// Raycasting algorithm
point = worldToScreen(point);
var j = points.length - 1;
var oddNodes = false;
@ -41,15 +62,15 @@ function insideShape(point)
j=i;
}
return (oddNodes ? 1 : 0);
return (oddNodes ? 2.7 : 0); // 1 kgm^-2
}
function massHelper(y, samples)
{
var origin = createVector(0, 0);
var h = width / samples;
var sum = 0.5 * (insideShape(createVector(0, y)) + insideShape(createVector(width, y)));
var h = canvasSize / samples;
var sum = 0.5 * (insideShape(createVector(0, y)) + insideShape(createVector(canvasSize, y)));
for(var i = 1; i <= samples - 1; i++)
{
@ -62,8 +83,8 @@ function massHelper(y, samples)
function mass(samples)
{
var h = height / samples;
var sum = 0.5 * (massHelper(0, samples) + massHelper(height, samples));
var h = canvasSize / samples;
var sum = 0.5 * (massHelper(0, samples) + massHelper(canvasSize, samples));
for(var i = 1; i <= samples - 1; i++)
{
@ -77,16 +98,16 @@ function momentOfInertiaHelper(y, samples)
{
var origin = createVector(0, 0);
var h = width / samples;
var h = canvasSize / samples;
var sum = 0.5 * (
insideShape(createVector(0, y)) * pow(createVector(0, y).dist(origin) / width, 2)
+ insideShape(createVector(width, y)) * pow(createVector(0, y).dist(origin) / width, 2)
insideShape(createVector(0, y)) * pow(createVector(0, y).dist(origin) / canvasSize, 2)
+ insideShape(createVector(canvasSize, y)) * pow(createVector(0, y).dist(origin) / canvasSize, 2)
);
for(var i = 1; i <= samples - 1; i++)
{
var point = createVector(i * h, y);
sum += insideShape(point) * pow(point.dist(origin) / width, 2)
sum += insideShape(point) * pow(point.dist(origin) / canvasSize, 2)
}
return h * sum;
@ -94,8 +115,8 @@ function momentOfInertiaHelper(y, samples)
function momentOfInertia(samples)
{
var h = height / samples;
var sum = 0.5 * (momentOfInertiaHelper(0, samples) + momentOfInertiaHelper(height, samples));
var h = canvasSize / samples;
var sum = 0.5 * (momentOfInertiaHelper(0, samples) + momentOfInertiaHelper(canvasSize, samples));
for(var i = 1; i <= samples - 1; i++)
{
@ -109,10 +130,10 @@ function centerOfMassHelper(y, samples)
{
var origin = createVector(0, 0);
var h = width / samples;
var h = canvasSize / samples;
var v0 = createVector(0, y);
var vn = createVector(width, y);
var vn = createVector(canvasSize, y);
v0.mult(insideShape(v0));
vn.mult(insideShape(vn));
@ -134,9 +155,9 @@ function centerOfMassHelper(y, samples)
function centerOfMass(samples) {
m = mass(samples);
var h = height / samples;
var h = canvasSize / samples;
var sum = centerOfMassHelper(0, samples);
sum.add(centerOfMassHelper(height, samples));
sum.add(centerOfMassHelper(canvasSize, samples));
sum.mult(0.5);
for(var i = 1; i <= samples - 1; i++)
{
@ -152,23 +173,24 @@ function centerOfMass(samples) {
function simulate()
{
acc = -m*g*L*sin(theta) / inertia;
if(abs(theta) > 0.0001) acc -= 2 * vel;
if(abs(theta) > 0.0001) acc -= 0.2 * vel;
console.log(degrees(theta));
vel += acc * deltaTime / 10000;
vel += acc * deltaTime / 1000;
var dtheta = theta;
theta += vel * deltaTime / 10000;
theta += vel * deltaTime / 1000;
dtheta -= theta;
dtheta *= -1;
worldAttach = screenToWorld(attachPoint);
points.forEach(function(item, index) {
item.sub(attachPoint);
item.rotate(-dtheta);
item.rotate(dtheta);
item.add(attachPoint);
});
centerMass.sub(attachPoint);
centerMass.rotate(-dtheta);
centerMass.add(attachPoint);
centerMass.sub(worldAttach);
centerMass.rotate(dtheta);
centerMass.add(worldAttach);
}
function setup()
@ -207,7 +229,8 @@ function draw()
endShape()
fill(50, 50, 255);
rect(centerMass.x - 5, centerMass.y - 5, 10, 10);
com = worldToScreen(centerMass);
rect(com.x - 5, com.y - 5, 10, 10);
}
if(!shapeComplete)
@ -261,7 +284,6 @@ function handleClick(event)
{
shapeComplete = true;
inertia = momentOfInertia(100);
console.log("Moment of inertia: " + inertia + " ML²");
centerMass = centerOfMass(100);
document.getElementById("inst").innerHTML = "Use your mouse to select the pivot point."
@ -272,11 +294,12 @@ function handleClick(event)
attachPoint = createVector(mouseX, mouseY);
attachPointSelected = true;
L = centerMass.dist(attachPoint);
var helper = createVector(attachPoint.x, attachPoint.y);
L = centerMass.dist(screenToWorld(attachPoint));
var helper = screenToWorld(attachPoint)
helper.sub(centerMass);
theta = helper.angleBetween(createVector(0, -1));
// alert(degrees(theta));
document.getElementById("inst").innerHTML = "Mass: " + m + " M --- Moment of inertia: " + inertia.toFixed(3) + " ML²";
document.getElementById("inst").innerHTML = "Mass: " + m + " kg --- Moment of inertia: " + inertia.toFixed(3) + " kgm^-2 --- Canvas is 2m wide --- Simulated material is aluminum";
}
}