Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Fix circles collision #4256 #4279

Merged
merged 1 commit into from
May 4, 2019
Merged

Fix circles collision #4256 #4279

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
97 changes: 13 additions & 84 deletions src/physics/arcade/World.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1504,11 +1504,6 @@ var World = new Class({
GetOverlapX(body1, body2, false, bias);
GetOverlapY(body1, body2, false, bias);

var dx = body2.center.x - body1.center.x;
var dy = body2.center.y - body1.center.y;

var angleCollision = Math.atan2(dy, dx);

var overlap = 0;

if (body1.isCircle !== body2.isCircle)
Expand Down Expand Up @@ -1568,94 +1563,28 @@ var World = new Class({
return (overlap !== 0);
}

// Transform the velocity vector to the coordinate system oriented along the direction of impact.
// This is done to eliminate the vertical component of the velocity

var b1vx = body1.velocity.x;
var b1vy = body1.velocity.y;
var b1mass = body1.mass;

var b2vx = body2.velocity.x;
var b2vy = body2.velocity.y;
var b2mass = body2.mass;

var v1 = {
x: b1vx * Math.cos(angleCollision) + b1vy * Math.sin(angleCollision),
y: b1vx * Math.sin(angleCollision) - b1vy * Math.cos(angleCollision)
};

var v2 = {
x: b2vx * Math.cos(angleCollision) + b2vy * Math.sin(angleCollision),
y: b2vx * Math.sin(angleCollision) - b2vy * Math.cos(angleCollision)
};

// We expect the new velocity after impact
var tempVel1 = ((b1mass - b2mass) * v1.x + 2 * b2mass * v2.x) / (b1mass + b2mass);
var tempVel2 = (2 * b1mass * v1.x + (b2mass - b1mass) * v2.x) / (b1mass + b2mass);
var dx = body1.position.x - body2.position.x;
var dy = body1.position.y - body2.position.y;
var d = Math.sqrt(Math.pow(dx, 2) + Math.pow(dy, 2));
var nx = (body2.position.x - body1.position.x) / d;
var ny = (body2.position.y - body1.position.y) / d;
var p = 2 * (body1.velocity.x * nx + body1.velocity.y * ny - body2.velocity.x * nx - body2.velocity.y * ny) / (body1.mass + body2.mass);

// We convert the vector to the original coordinate system and multiplied by factor of rebound
if (!body1.immovable)
{
body1.velocity.x = (tempVel1 * Math.cos(angleCollision) - v1.y * Math.sin(angleCollision)) * body1.bounce.x;
body1.velocity.y = (v1.y * Math.cos(angleCollision) + tempVel1 * Math.sin(angleCollision)) * body1.bounce.y;

// Reset local var
b1vx = body1.velocity.x;
b1vy = body1.velocity.y;
body1.velocity.x = (body1.velocity.x - p * body1.mass * nx) * body1.bounce.x;
body1.velocity.y = (body1.velocity.y - p * body1.mass * ny) * body1.bounce.y;
}

if (!body2.immovable)
{
body2.velocity.x = (tempVel2 * Math.cos(angleCollision) - v2.y * Math.sin(angleCollision)) * body2.bounce.x;
body2.velocity.y = (v2.y * Math.cos(angleCollision) + tempVel2 * Math.sin(angleCollision)) * body2.bounce.y;

// Reset local var
b2vx = body2.velocity.x;
b2vy = body2.velocity.y;
body2.velocity.x = (body2.velocity.x + p * body2.mass * nx) * body2.bounce.x;
body2.velocity.y = (body2.velocity.y + p * body2.mass * ny) * body2.bounce.y;
}

// When the collision angle is almost perpendicular to the total initial velocity vector
// (collision on a tangent) vector direction can be determined incorrectly.
// This code fixes the problem

if (Math.abs(angleCollision) < Math.PI / 2)
{
if ((b1vx > 0) && !body1.immovable && (b2vx > b1vx))
{
body1.velocity.x *= -1;
}
else if ((b2vx < 0) && !body2.immovable && (b1vx < b2vx))
{
body2.velocity.x *= -1;
}
else if ((b1vy > 0) && !body1.immovable && (b2vy > b1vy))
{
body1.velocity.y *= -1;
}
else if ((b2vy < 0) && !body2.immovable && (b1vy < b2vy))
{
body2.velocity.y *= -1;
}
}
else if (Math.abs(angleCollision) > Math.PI / 2)
{
if ((b1vx < 0) && !body1.immovable && (b2vx < b1vx))
{
body1.velocity.x *= -1;
}
else if ((b2vx > 0) && !body2.immovable && (b1vx > b2vx))
{
body2.velocity.x *= -1;
}
else if ((b1vy < 0) && !body1.immovable && (b2vy < b1vy))
{
body1.velocity.y *= -1;
}
else if ((b2vy > 0) && !body2.immovable && (b1vx > b2vy))
{
body2.velocity.y *= -1;
}
}
var dvx = body2.velocity.x - body1.velocity.x;
var dvy = body2.velocity.y - body1.velocity.y;
var angleCollision = Math.atan2(dvy, dvx);

var delta = this._frameTime;

Expand Down