Any significant performance improvement by using bitwise operators instead of plain int sums in C#?
- by tunnuz
Hello, I started working with C# a few weeks ago and I'm now in a situation where I need to build up a "bit set" flag to handle different cases in an algorithm. I have thus two options:
enum RelativePositioning
{
LEFT = 0,
RIGHT = 1,
BOTTOM = 2,
TOP = 3,
FRONT = 4,
BACK = 5
}
pos = ((eye.X < minCorner.X ? 1 : 0) << RelativePositioning.LEFT)
+ ((eye.X > maxCorner.X ? 1 : 0) << RelativePositioning.RIGHT)
+ ((eye.Y < minCorner.Y ? 1 : 0) << RelativePositioning.BOTTOM)
+ ((eye.Y > maxCorner.Y ? 1 : 0) << RelativePositioning.TOP)
+ ((eye.Z < minCorner.Z ? 1 : 0) << RelativePositioning.FRONT)
+ ((eye.Z > maxCorner.Z ? 1 : 0) << RelativePositioning.BACK);
Or:
enum RelativePositioning
{
LEFT = 1,
RIGHT = 2,
BOTTOM = 4,
TOP = 8,
FRONT = 16,
BACK = 32
}
if (eye.X < minCorner.X) { pos += RelativePositioning.LEFT; }
if (eye.X > maxCorner.X) { pos += RelativePositioning.RIGHT; }
if (eye.Y < minCorner.Y) { pos += RelativePositioning.BOTTOM; }
if (eye.Y > maxCorner.Y) { pos += RelativePositioning.TOP; }
if (eye.Z > maxCorner.Z) { pos += RelativePositioning.FRONT; }
if (eye.Z < minCorner.Z) { pos += RelativePositioning.BACK; }
I could have used something as ((eye.X > maxCorner.X) << 1) but C# does not allow implicit casting from bool to int and the ternary operator was similar enough. My question now is: is there any performance improvement in using the first version over the second?
Thank you
Tommaso
