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Reduce memory usage to improve GC performance

This commit is contained in:
Mattéo Delabre 2020-05-04 18:17:25 +02:00
parent 11ffc81848
commit 9c9afa2409
Signed by: matteo
GPG Key ID: AE3FBD02DC583ABB
3 changed files with 93 additions and 77 deletions
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98
boids.mjs
View File

@ -1,79 +1,75 @@
import Vector from './vector.mjs';
const findNeighbors = (boids, boid, radius) =>
{
const neighbors = [];
for (let otherBoid of boids)
{
if (boid != otherBoid)
{
const dist = boid.pos.sub(otherBoid.pos).normSquared();
if (dist < radius * radius)
{
neighbors.push(otherBoid);
}
}
}
return neighbors;
};
const meanPos = new Vector(0, 0);
const meanVel = new Vector(0, 0);
const repelForce = new Vector(0, 0);
export const update = (boids, params, time) =>
{
for (let boid of boids)
{
const visible = findNeighbors(boids, boid, params.visibleDist);
const close = findNeighbors(boids, boid, params.closeDist);
const boidsSize = boids.length;
// Attract towards center of visible flock
const center = new Vector(0, 0);
for (let otherBoid of visible)
for (let i = 0; i < boidsSize; ++i)
{
center.addMut(otherBoid.pos);
const me = boids[i];
meanPos.reset();
meanVel.reset();
repelForce.reset();
let visibleSize = 0;
for (let j = 0; j < boidsSize; ++j)
{
if (i != j)
{
const you = boids[j];
const dist = Vector.distSquared(me.pos, you.pos);
if (dist < params.visibleDist * params.visibleDist)
{
meanPos.add(you.pos);
meanVel.add(you.vel);
visibleSize += 1;
if (dist < params.closeDist * params.closeDist)
{
repelForce.add(me.pos).sub(you.pos);
}
}
}
}
if (visible.length >= 1)
// Attract towards center of visible flock
if (visibleSize >= 1)
{
center.divMut(visible.length);
boid.vel.addMut(center.sub(boid.pos).mul(params.centerAccel));
me.vel.add(meanPos.div(visibleSize)
.sub(me.pos)
.mul(params.centerAccel));
}
// Attract toward center of screen
boid.vel.addMut(boid.pos.mul(-0.01));
me.vel.addMul(me.pos, -0.01);
// Repel away from close boids
for (let otherBoid of close)
{
boid.vel.addMut(boid.pos
.sub(otherBoid.pos)
.mul(params.repelAccel));
}
me.vel.add(repelForce.mul(params.repelAccel));
// Match other boids’ velocity
const velocity = new Vector(0, 0);
for (let otherBoid of visible)
if (visibleSize >= 1)
{
velocity.addMut(otherBoid.vel);
}
if (visible.length >= 1)
{
velocity.divMut(visible.length);
boid.vel.addMut(velocity.sub(boid.vel).mul(params.matchAccel));
me.vel.add(meanVel.div(visibleSize)
.sub(me.vel)
.mul(params.matchAccel));
}
// Do not surpass maximum speed
const speed = boid.vel.normSquared();
const speed = me.vel.normSquared();
if (speed > params.maxSpeed * params.maxSpeed)
{
boid.vel.divMut(Math.sqrt(speed)).mulMut(params.maxSpeed);
me.vel.div(Math.sqrt(speed)).mul(params.maxSpeed);
}
boid.pos.addMut(boid.vel.mul(time));
// Integrate speed
me.pos.addMul(me.vel, time);
}
};

24
draw.mjs
View File

@ -7,8 +7,13 @@ const boidShape = [
new Vector(2, 0),
];
const boidShapeSize = boidShape.length;
const transformed = new Vector(0, 0);
export const boids = (activeBoids, params, ctx, width, height, center) =>
{
const boidsSize = activeBoids.length;
ctx.clearRect(0, 0, width, height);
// // Draw each boid’s visibility and proximity zones
@ -75,24 +80,31 @@ export const boids = (activeBoids, params, ctx, width, height, center) =>
ctx.beginPath();
ctx.fillStyle = 'black';
for (let boid of activeBoids)
for (let i = 0; i < boidsSize; ++i)
{
const boid = activeBoids[i];
const angle = boid.vel.angle();
let isFirst = true;
for (let point of boidShape)
for (let j = 0; j < boidShapeSize; ++j)
{
const trans = boid.pos.add(center)
.add(point.rotate(angle).mul(params.radius))
transformed.x = boidShape[j].x;
transformed.y = boidShape[j].y;
transformed
.rotate(angle)
.mul(params.radius)
.add(center)
.add(boid.pos);
if (isFirst)
{
ctx.moveTo(trans.x, trans.y);
ctx.moveTo(transformed.x, transformed.y);
isFirst = false;
}
else
{
ctx.lineTo(trans.x, trans.y);
ctx.lineTo(transformed.x, transformed.y);
}
}
}

52
vector.mjs
View File

@ -7,23 +7,20 @@ class Vector
}
add(vector)
{
return new Vector(this.x + vector.x, this.y + vector.y);
}
addMut(vector)
{
this.x += vector.x;
this.y += vector.y;
return this;
}
sub(vector)
addMul(vector, scalar)
{
return new Vector(this.x - vector.x, this.y - vector.y);
this.x += vector.x * scalar;
this.y += vector.y * scalar;
return this;
}
subMut(vector)
sub(vector)
{
this.x -= vector.x;
this.y -= vector.y;
@ -31,11 +28,6 @@ class Vector
}
mul(scalar)
{
return new Vector(this.x * scalar, this.y * scalar);
}
mulMut(scalar)
{
this.x *= scalar;
this.y *= scalar;
@ -47,20 +39,16 @@ class Vector
return this.mul(1 / scalar);
}
divMut(scalar)
{
return this.mulMut(1 / scalar);
}
rotate(angle)
{
const cos = Math.cos(angle);
const sin = Math.sin(angle);
const nextX = cos * this.x - sin * this.y;
const nextY = cos * this.y + sin * this.x;
return new Vector(
cos * this.x - sin * this.y,
cos * this.y + sin * this.x,
);
this.x = nextX;
this.y = nextY;
return this;
}
angle()
@ -72,6 +60,26 @@ class Vector
{
return this.x * this.x + this.y * this.y;
}
static distSquared(lhs, rhs)
{
return (
(lhs.x - rhs.x) * (lhs.x - rhs.x)
+ (lhs.y - rhs.y) * (lhs.y - rhs.y)
);
}
reset()
{
this.x = 0;
this.y = 0;
return this;
}
clone()
{
return new Vector(this.x, this.y);
}
}
export default Vector;