Method update

src/engineParticles.js:380–461

Update the particle

()

    /** Update the particle */
    update()
    {
        // emitter properties
        const emitter = this.emitter;
        const damping = emitter.damping;
        const angleDamping = emitter.angleDamping;
        const restitution = emitter.restitution;
        const friction = emitter.friction;
        const gravityScale = emitter.gravityScale;
        const collideTiles = emitter.collideTiles;
        const collideCallback = emitter.particleCollideCallback;

        // destroy particle when its time runs out
        if (this.lifeTime > 0 && time - this.spawnTime > this.lifeTime)
        {
            this.destroy();
            return;
        }

        // apply physics
        const oldPos = this.pos.copy();
        this.velocity.x *= damping;
        this.velocity.y *= damping;
        this.pos.x += this.velocity.x += gravity.x * gravityScale;
        this.pos.y += this.velocity.y += gravity.y * gravityScale;
        this.angle += this.angleVelocity *= angleDamping;

        // don't do collision if solver disabled
        if (!enablePhysicsSolver || !collideTiles) return;
        
        // apply max circular speed to prevent going through collision
        const length2 = this.velocity.lengthSquared();
        if (length2 > objectMaxSpeed*objectMaxSpeed)
        {
            const s = objectMaxSpeed / length2**.5;
            this.velocity.x *= s;
            this.velocity.y *= s;
        }

        // check collision against tiles
        this.groundObject = undefined;
        const testCollision = collideCallback ? (pos)=>
        {
            const data = tileCollisionGetData(pos);
            return data && collideCallback(this, data, pos);
        } : (pos)=> tileCollisionGetData(pos) > 0;

        if (testCollision(this.pos))
        {
            // if already was stuck in collision, don't do anything
            const hitLayer = tileCollisionTest(this.pos);
            if (!testCollision(oldPos))
            {
                // testCollision already invoked collideCallback with the
                // correct (this, data, pos) args; no need to re-check here.
                // test which side we bounced off (or both if a corner)
                const isBlockedX = testCollision(vec2(this.pos.x, oldPos.y));
                const isBlockedY = testCollision(vec2(oldPos.x, this.pos.y));