The Daily WTF: Curious Perversions in Information Technology

Steve_The_Cynic · 2026-09-30 Reply Edit Admin

You or I would likely try and answer this question using a simple distance calculation

You might do that, but I wouldn't, or at least not with a strict application of "simple distance calculation". I would compare deltaX*deltaX + deltaY*deltaY to radius*radius to avoid calculating the square root that's required for a "simple distance calculation".

2026-09-30 Reply Admin

Am I missing something? This is not looking for a box, it is looking for a specific point?

2026-09-30 Reply Admin

Yeah, pretty much what I did, except for integer overflow, and floating point was too slow…

2026-09-30 Reply Admin

Yes, but the nested for loops are iterating over every point in a radius x radius box to see if the desired point is in there. You could get a false positive if the point is in the corner of the box, outside the radius circle.

2026-09-30 Reply Admin

A 'simple' distance calculation is not WTFy enough... try this.

double deltaX = PositionX - point.X; double deltaY = PositionY - point.Y; double angle = double.Atan2(deltaX, deltaY); double distance = deltaX * Math.Sin(angle) + deltaY * Math.Cos(angle);

2026-09-30

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Quite a Distance from the Right Solution

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