ImpactJS -在传递给类构造函数之后变为NaN之前有效的变量值

Question

很抱歉发了这么长的帖子，但我想尽可能的详细。

因此，我正在创建一个带有两个自定义ig.Class实例的插件。一个是向量实现：Vec2，然后我有一个粒子类：

Particle = ig.Class.extend({
    pos: null,
    last: null,
    init: function (pos) {
        this.pos = new Vec2().mutableSet(pos.x, pos.y);
        this.last = this.pos;
    },
    draw: function (ctx) {
        ctx.beginPath();
        ctx.arc(this.pos.x, this.pos.y, 2, 0, 2 * Math.PI);
        ctx.fillStyle = "#2dad8f";
        ctx.fill();
    }
});

接下来，我在另一个类中使用了这个轮胎函数：

tire: function (origin, radius, segments, spokeStiffness, treadStiffness) {
        var stride = (2 * Math.PI) / segments;

        var composite = new Composite();

        // particles
        for (var i = 0; i < segments; i++) {
            var theta = i * stride;
            composite.particles.push(new Particle(new Vec2(origin.x + Math.cos(theta) * radius, origin.y + Math.sin(theta) * radius)));
        }
        var center = new Particle(origin);
        composite.particles.push(center);
        // constraints
        for (i = 0; i < segments; i++) {
            composite.constraints.push(new DistanceConstraint(composite.particles[i], composite.particles[(i + 1) % segments], treadStiffness));
            composite.constraints.push(new DistanceConstraint(composite.particles[i], center, spokeStiffness))
            composite.constraints.push(new DistanceConstraint(composite.particles[i], composite.particles[(i + 5) % segments], treadStiffness));
        }

        this.composites.push(composite);
        return composite;
    }

最后，此更新函数位于与轮胎函数相同的类中：

update: function (step) {
        for (var c in this.composites) {
            for (var i in this.composites[c].particles) {
                var particles = this.composites[c].particles;
                // calculate velocity
                var velocity = particles[i].pos.sub(particles[i].last).scale(this.friction);

                // ground friction
                if (particles[i].pos.y >= this.height - 1 && velocity.length2() > 0.000001) {
                    var m = velocity.length();
                    velocity.x /= m;
                    velocity.y /= m;
                    velocity.mutableScale(m * this.groundFriction);
                }

                // save last good state
                particles[i].last.mutableSet(particles[i].pos);

                // gravity
                particles[i].pos.mutableAdd(this.gravity);

                // inertia  
                particles[i].pos.mutableAdd(velocity);
            }
        }
        // relax
        var stepCoef = 1 / step;
        for (var c in this.composites) {
            var constraints = this.composites[c].constraints;
            for (var i = 0; i < step; ++i) {
                for (var j in constraints) {
                    constraints[j].relax(stepCoef);
                }
            }
        }

        // bounds checking
        for (var c in this.composites) {
            var particles = this.composites[c].particles;
            for (var i in particles) {
                this.bounds(particles[i]);
            }
        }
    }

我得到的错误是在update函数中的这一行：var velocity = particles[i].pos.sub(particles[i].last).scale(this.friction);，具体地说，错误是说它不能调用未定义的方法sub。我更改了上面的轮胎方法，如下所示，这样我就可以调试它了：

tire: function (origin, radius, segments, spokeStiffness, treadStiffness) {
        var stride = (2 * Math.PI) / segments;

        var composite = new Composite();

        // particles
        for (var i = 0; i < segments; i++) {
            var theta = i * stride;
            var x = origin.x + Math.cos(theta) * radius;
            var y = origin.y + Math.sin(theta) * radius;
            var pos = new Vec2(x, y);
            console.log(pos);
            var particle = new Particle(pos);
            composite.particles.push(particle);
        }
        var center = new Particle(origin);
        composite.particles.push(center);
        // constraints
        for (i = 0; i < segments; i++) {
            composite.constraints.push(new DistanceConstraint(composite.particles[i], composite.particles[(i + 1) % segments], treadStiffness));
            composite.constraints.push(new DistanceConstraint(composite.particles[i], center, spokeStiffness))
            composite.constraints.push(new DistanceConstraint(composite.particles[i], composite.particles[(i + 5) % segments], treadStiffness));
        }

        this.composites.push(composite);
        return composite;
    }

当我记录pos变量时，我得到了输出到控制台的正确的值，但是如果仍然得到错误的话。我能想到的唯一一件事是，在tire方法中创建pos变量的地方，以及在Particle构造函数中传递和赋值它时，它会丢失它的值，并导致粒子的pos.x / pos.y值为NaN，当我将变量particles记录在错误线(var velocity = particles[i].pos.sub(particles[i].last).scale(this.friction);)之上时，我可以看到这一点。我真的不知道哪里出了问题，我试着改变Particle构造函数对参数pos的赋值，使其以多种方式赋值(通过Vec2.mutableSet()方法和直接设置)。但无论我做什么，它仍然会导致粒子的NaN值。

有人能看到我不是的东西吗？谢谢

Answer 1

弄清楚了，有一个javascript文件正在被加载，它覆盖了Particle类。删除了javascript文件的script标记，一切正常