Circle Collision JavaScript
/*
You should call the function resolveCollsion, when a collision between two
circles is detected.
*/
function rotate(velocity, angle) {
const rotatedVelocities = {
x: velocity.x * Math.cos(angle) - velocity.y * Math.sin(angle),
y: velocity.x * Math.sin(angle) + velocity.y * Math.cos(angle)
}
return rotatedVelocities;
}
function resolveCollision(particle, otherParticle) {
/*
the particles passed as parameters should be objects with
x and y position,
a velocity object with x and y values,
a mass value
as attributes
example of a class:
function Circle() {
this.x = x;
this.y = y;
this.velocity = {
x: 5,
y: 5
};
this.mass = 2;
}
*/
const xVelocityDiff = particle.velocity.x - otherParticle.velocity.x;
const yVelocityDiff = particle.velocity.y - otherParticle.velocity.y;
const xDist = otherParticle.x - particle.x;
const yDist = otherParticle.y - particle.y;
if (xVelocityDiff * xDist + yVelocityDiff * yDist >= 0) {
const angle = -Math.atan2(otherParticle.y - particle.y, otherParticle.x - particle.x);
const m1 = particle.mass;
const m2 = otherParticle.mass;
const u1 = rotate(particle.velocity, angle);
const u2 = rotate(otherParticle.velocity, angle);
const v1 = { x: u1.x * (m1 - m2) / (m1 + m2) + u2.x * 2 * m2 / (m1 + m2), y: u1.y };
const v2 = { x: u2.x * (m1 - m2) / (m1 + m2) + u1.x * 2 * m2 / (m1 + m2), y: u2.y };
const vFinal1 = rotate(v1, -angle);
const vFinal2 = rotate(v2, -angle);
particle.velocity.x = vFinal1.x;
particle.velocity.y = vFinal1.y;
otherParticle.velocity.x = vFinal2.x;
otherParticle.velocity.y = vFinal2.y;
}
}
/*
source:
https://youtu.be/789weryntzM
*/
Shy Skimmer
