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move charge repelling stuff to its own file

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root 2025-04-25 08:56:49 +00:00
parent fb6b8aa33c
commit 6cbdb04786
3 changed files with 46 additions and 41 deletions
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1
index.html
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@ -16,6 +16,7 @@ body {
<body>
<main>
</main>
<script src="thomson-problem.js"></script>
<script src="sketch.js"></script>
</body>
</html>

42
sketch.js
View file

@ -19,52 +19,12 @@ function draw() {
make_lights();
if (physics) {
move_charges();
move_charges(charges);
}
draw_charges(sphere_radius);
draw_sphere(sphere_radius, 25);
}
function move_charges() {
for (charge of charges) {
charge.acceleration.setMag(0);
}
for (let i = 0; i < charges.length; i += 1) {
for (let j = 0; j < i; j += 1) {
const displacement = p5.Vector.sub(
charges[i].position,
charges[j].position,
);
const acceleration_mag = 1 / displacement.mag() * 0.001;
let ai = displacement.copy().normalize().mult(acceleration_mag);
let aj = p5.Vector.mult(ai, -1);
project_onto_plane(ai, charges[i].position);
project_onto_plane(aj, charges[j].position);
charges[i].acceleration.add(ai);
charges[j].acceleration.add(aj);
}
}
for (let i = 0; i < charges.length; i += 1) {
let charge = charges[i];
charge.velocity = charge.velocity.add(charge.acceleration);
//project_onto_plane(charge.velocity, charge.position);
charge.position = charge.position.add(charge.velocity);
charge.position.normalize();
}
}
function project_onto_unit_vector(v, unit_vector) {
let size = p5.Vector.dot(v, unit_vector);
return p5.Vector.mult(unit_vector, size);
}
/// Project `v` onto the plane normal to `unit_vector`
/// Mutates `v`
function project_onto_plane(v, unit_vector) {
let v_proj = project_onto_unit_vector(v, unit_vector);
v.sub(v_proj)
}
function make_charges(n) {
charges = [];
for (let i = 0; i < n; i += 1) {

44
thomson-problem.js Normal file
View file

@ -0,0 +1,44 @@
function move_charges(charges) {
for (charge of charges) {
charge.acceleration.setMag(0);
}
for (let i = 0; i < charges.length; i += 1) {
for (let j = 0; j < i; j += 1) {
const displacement = p5.Vector.sub(
charges[i].position,
charges[j].position,
);
let acceleration_mag = 1 / displacement.mag() * 0.001;
let ai;
if (acceleration_mag === Infinity) {
ai = createVector(random(-1, 1), random(-1, 1), random(-1, 1));
} else {
ai = displacement.copy();
}
ai = ai.normalize().mult(acceleration_mag);
let aj = p5.Vector.mult(ai, -1);
project_onto_plane(ai, charges[i].position);
project_onto_plane(aj, charges[j].position);
charges[i].acceleration.add(ai);
charges[j].acceleration.add(aj);
}
}
for (let i = 0; i < charges.length; i += 1) {
let charge = charges[i];
charge.velocity = charge.velocity.add(charge.acceleration);
charge.position = charge.position.add(charge.velocity);
charge.position.normalize();
}
}
function project_onto_unit_vector(v, unit_vector) {
let size = p5.Vector.dot(v, unit_vector);
return p5.Vector.mult(unit_vector, size);
}
/// Project `v` onto the plane normal to `unit_vector`
/// Mutates `v`
function project_onto_plane(v, unit_vector) {
let v_proj = project_onto_unit_vector(v, unit_vector);
v.sub(v_proj)
}