Bezier curve algorithm in objective-c

Can someone smarter than me look at this. I am trying to implement a Bezier curve algorithm. I found here in objective-c.

The result is incorrect. I think I converted the code correctly, so either the original was wrong or not used for use in this way ... If I use the built-in NSBezierPath, the curve looks great, but I can not use the built-in NSBezierPath.

NSBezierPath Example

NSBezierPath *bezierPath = [[NSBezierPath alloc] init];
[bezierPath setLineWidth:1.0f];
[bezierPath moveToPoint:NSMakePoint(x1, y1)];
[bezierPath curveToPoint:NSMakePoint(x4, y4) controlPoint1:NSMakePoint(x2, y2) controlPoint2:NSMakePoint(x3, y3)];

My code is trying to draw a bezier curve

- (void)drawBezierFrom:(NSPoint)from to:(NSPoint)to controlA:(NSPoint)a controlB:(NSPoint)b color:(NSUInteger)color
{
    float qx, qy;
    float q1, q2, q3, q4;
    int plotx, ploty;
    float t = 0.0;

    while (t <= 1)
    {
        q1 = t*t*t*-1 + t*t*3 + t*-3 + 1;
        q2 = t*t*t*3 + t*t*-6 + t*3;
        q3 = t*t*t*-3 + t*t*3;
        q4 = t*t*t;

        qx = q1*from.x + q2*to.x * q3*a.x + q4*b.x;
        qy = q1*from.y + q2*to.y * q3*a.y + q4*b.y;

        plotx = round(qx);
        ploty = round(qy);

        [self drawPixelColor:color atX:plotx y:ploty];

        t = t + 0.003;
    }
}

Edit

See The Bezier Curve Algorithm in objective-c needs to be set up for the completed Bezier Functional Method.