43 lines
1.3 KiB
JavaScript
43 lines
1.3 KiB
JavaScript
function move_charges(charges) {
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for (let charge of charges) {
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charge.acceleration.setMag(0);
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}
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for (let i = 0; i < charges.length; i += 1) {
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for (let j = 0; j < i; j += 1) {
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const displacement = p5.Vector.sub(
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charges[i].position,
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charges[j].position,
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);
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let acceleration_mag = 1 / displacement.mag() * 0.001;
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let ai;
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if (acceleration_mag === Infinity) {
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ai = p5.Vector.random3D();
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} else {
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ai = displacement.copy().normalize();
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}
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ai.mult(acceleration_mag);
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let aj = p5.Vector.mult(ai, -1);
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project_onto_plane(ai, charges[i].position);
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project_onto_plane(aj, charges[j].position);
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charges[i].acceleration.add(ai);
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charges[j].acceleration.add(aj);
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}
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}
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for (let charge of charges) {
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charge.velocity = charge.velocity.add(charge.acceleration);
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charge.position = charge.position.add(charge.velocity);
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charge.position.normalize();
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}
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}
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function project_onto_unit_vector(v, unit_vector) {
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let size = p5.Vector.dot(v, unit_vector);
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return p5.Vector.mult(unit_vector, size);
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}
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/// Project `v` onto the plane normal to `unit_vector`
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/// Mutates `v`
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function project_onto_plane(v, unit_vector) {
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let v_proj = project_onto_unit_vector(v, unit_vector);
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v.sub(v_proj)
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}
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