Method update

src/engineParticles.js:186–233

Update the emitter to spawn particles, called automatically by engine once each frame

()

    /** Update the emitter to spawn particles, called automatically by engine once each frame */
    update()
    {
        // physics sanity checks
        ASSERT(this.angleDamping >= 0 && this.angleDamping <= 1);
        ASSERT(this.damping >= 0 && this.damping <= 1);

        if (this.velocityInheritance)
        {
            // pass emitter velocity to particles
            const p = this.velocityInheritance;
            this.velocity.x = p * (this.pos.x - this.previousPos.x);
            this.velocity.y = p * (this.pos.y - this.previousPos.y);
            this.angleVelocity = p * (this.angle - this.previousAngle);
            this.previousAngle = this.angle;
            this.previousPos.x = this.pos.x;
            this.previousPos.y = this.pos.y;
        }

        // update emitter
        if (this.isActive())
        {
            // emit particles
            if (this.emitRate && particleEmitRateScale)
            {
                const rate = 1/this.emitRate/particleEmitRateScale;
                for (this.emitTimeBuffer += timeDelta; this.emitTimeBuffer > 0; this.emitTimeBuffer -= rate)
                    this.emitParticle();
            }
        }
        else if (this.particles.length === 0)
            this.destroy(true);
            
        // update and remove destroyed particles
        this.particles = this.particles.filter((p)=>
        {
            p.update();
            return !p.destroyed;
        });

        if (debugParticles)
        {
            // show emitter bounds
            if (this.emitCircle)
                debugCircle(this.pos, this.emitSize.x/2, '#0f0');
            else
                debugRect(this.pos, this.emitSize, '#0f0', 0, this.angle);
        }
    }

    /** Spawn one particle
     *  @return {Particle} */