Box2D Forums

  // Original
  val v: org.villane.vecmath.Vector2 = v1.-(v2).×(-2.0);
  // Optimized
  val v$x: Float = v1.y.-(v2.y).*(-2.0);
  val v$y: Float = v1.x.-(v2.x).*(-2.0.unary_-); // -(-2) should be optimized later anyway before bytecode generation

  // Original
  var vd = Preamble.floatToFloatExtensions(v2.-(v1).dot(v3)).*(new Vector2(1.0, 3.0));
  var vx = Preamble.floatToFloatExtensions(v2.-(v1).cross(v3)).*(new Vector2(1.0, 3.0));
  vx.-(vd)
  // "Optimized" (actually at least v2 - v1 should be cached!!!)
  var vd$x: Float = v2.x.-(v1.x).*(v3.x).+(v2.y.-(v1.y).*(v3.y)).*(1.0);
  var vd$y: Float = v2.x.-(v1.x).*(v3.x).+(v2.y.-(v1.y).*(v3.y)).*(3.0);
  var vx$x: Float = v2.x.-(v1.x).*(v3.y).-(v2.y.-(v1.y).*(v3.x)).*(1.0);
  var vx$y: Float = v2.x.-(v1.x).*(v3.y).-(v2.y.-(v1.y).*(v3.x)).*(3.0);
  new org.villane.vecmath.Vector2(vx$x.-(vd$x), vx$y.-(vd$y))

--- ORIGINAL SOURCE ---
@org.villane.vecmath.optimizer.sr def testSegment(segment: org.villane.box2d.shapes.Segment, maxLambda: Float): org.villane.box2d.shapes.SegmentCollide = {
  val s: org.villane.vecmath.Vector2 = segment.p1;
  val r: org.villane.vecmath.Vector2 = segment.p2.-(s);
  val d: org.villane.vecmath.Vector2 = Segment.this.p2.-(Segment.this.p1);
  val n: org.villane.vecmath.Vector2 = d.cross(1.0);
  val slop: Float = 100.0.*(Settings.Epsilon);
  val denom: Float = r.dot(n).unary_-;
  if (denom.>(slop))
    {
      val b: org.villane.vecmath.Vector2 = s.-(Segment.this.p1);
      val a: Float = b.dot(n);
      if (0.0.<=(a).&&(a.<=(maxLambda.*(denom))))
        {
          val mu2: Float = b.cross(r);
          if (slop.unary_-.*(denom).<=(mu2).&&(mu2.<=(denom.*(1.0.+(slop)))))
            return SegmentCollide.hit(a./(denom), n.normalize)
        }
    };
  SegmentCollide.Miss
}
--- OPTIMIZED SOURCE ---
@org.villane.vecmath.optimizer.sr def testSegment(segment: org.villane.box2d.shapes.Segment, maxLambda: Float): org.villane.box2d.shapes.SegmentCollide = {
  val s$x: Float = segment.p1.x;
  val s$y: Float = segment.p1.y;
  val r$x: Float = segment.p2.x.-(s$x);
  val r$y: Float = segment.p2.y.-(s$y);
  val d$x: Float = Segment.this.p2.x.-(Segment.this.p1.x);
  val d$y: Float = Segment.this.p2.y.-(Segment.this.p1.y);
  val n$x: Float = d$y.*(1.0);
  val n$y: Float = d$x.*(1.0.unary_-);
  val slop: Float = 100.0.*(Settings.Epsilon);
  val denom: Float = r$x.*(n$x).+(r$y.*(n$y)).unary_-;
  if (denom.>(slop))
    {
      val b$x: Float = s$x.-(Segment.this.p1.x);
      val b$y: Float = s$y.-(Segment.this.p1.y);
      val a: Float = b$x.*(n$x).+(b$y.*(n$y));
      if (0.0.<=(a).&&(a.<=(maxLambda.*(denom))))
        {
          val mu2: Float = b$x.*(r$y).-(b$y.*(r$x));
          if (slop.unary_-.*(denom).<=(mu2).&&(mu2.<=(denom.*(1.0.+(slop)))))
            {
              val n$length: Float = Preamble.sqrt(n$x.*(n$x).+(n$y.*(n$y)));
              return SegmentCollide.hit(a./(denom), new org.villane.vecmath.Vector2(n$x./(n$length), n$y./(n$length)))
            }
        }
    };
  SegmentCollide.Miss
}

2046 ms (old version, with manual optimizations)
 first 100: 375 ms
 last  900: 1671 ms
vectors created:22868550

2703 ms (compiled normally)
 first 100: 344 ms
 last  900: 2359 ms
vectors created:140496823

2297 ms (compiled with optimizer)
 first 100: 312 ms
 last  900: 1985 ms
vectors created:20375221

val dot = new Vector2(normals1.apply(i).x, normals1.apply(i).y).x.*(dlx).+(new Vector2(normals1.apply(i).x, normals1.apply(i).y).y.*(dly))