Eliminated LengthSquared > 0 for slight performance #13609
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Do you have profiling numbers demonstrating improvement? |
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I know is extreme to have 50 rocket guys shooting all at the same time but: https://www.youtube.com/watch?v=3LSQooExybM : Before - Max 5 ms per tick I think it makes difference. |
| @@ -68,7 +68,7 @@ public override Activity Tick(Actor self) | |||
| if (host.Type == TargetType.Invalid || health == null) | |||
| return NextActivity; | |||
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| if (closeEnough.LengthSquared > 0 && !host.IsInRange(self.CenterPosition, closeEnough)) | |||
| if (closeEnough.Length != 0 && !host.IsInRange(self.CenterPosition, closeEnough)) | |||
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Why is LengthSquared replaced with Length here?
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In Repair.cs, closeEnough is WDist class, who already has Length inside the class and computing LengthSquared is an extra work.
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OK. WDist is a struct actually (not that that matters here).
Maybe closeEnough != WDist.Zero should be used.
| @@ -68,7 +68,7 @@ public override Activity Tick(Actor self) | |||
| if (host.Type == TargetType.Invalid || health == null) | |||
| return NextActivity; | |||
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| if (closeEnough.LengthSquared > 0 && !host.IsInRange(self.CenterPosition, closeEnough)) | |||
| if (closeEnough != WDist.Zero && !host.IsInRange(self.CenterPosition, closeEnough)) | |||
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WDist supports >, so you should revert the != to make sure there won't be any unwanted behavior.
Edit: Actually, looking at how the WDist operators work, I suspect just using .Length instead of LengthSquared will have the biggest benefit over bleed here.
| @@ -573,7 +573,7 @@ int IncreaseAltitude(int predClfDist, int diffClfMslHgt, int relTarHorDist, int | |||
| { | |||
| // Aim for the target | |||
| var vDist = new WVec(-relTarHgt, -relTarHorDist, 0); | |||
| desiredVFacing = (sbyte)vDist.HorizontalLengthSquared != 0 ? vDist.Yaw.Facing : vFacing; | |||
| desiredVFacing = (sbyte)(vDist.HasNonZeroHorizontalLength ? vDist.Yaw.Facing : vFacing); | |||
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vDist.Z is guaranteed to be 0 here, so you can simply check for vDist != WVec.Zero instead.
| @@ -666,7 +666,7 @@ int IncreaseAltitude(int predClfDist, int diffClfMslHgt, int relTarHorDist, int | |||
| { | |||
| // Aim for the target | |||
| var vDist = new WVec(-relTarHgt, -relTarHorDist, 0); | |||
| desiredVFacing = (sbyte)vDist.HorizontalLengthSquared != 0 ? vDist.Yaw.Facing : vFacing; | |||
| desiredVFacing = (sbyte)(vDist.HasNonZeroHorizontalLength ? vDist.Yaw.Facing : vFacing); | |||
| @@ -676,7 +676,7 @@ int IncreaseAltitude(int predClfDist, int diffClfMslHgt, int relTarHorDist, int | |||
| { | |||
| // Aim for the target | |||
| var vDist = new WVec(-relTarHgt, relTarHorDist, 0); | |||
| desiredVFacing = (sbyte)vDist.HorizontalLengthSquared != 0 ? vDist.Yaw.Facing : vFacing; | |||
| desiredVFacing = (sbyte)(vDist.HasNonZeroHorizontalLength ? vDist.Yaw.Facing : vFacing); | |||
| @@ -686,7 +686,7 @@ int IncreaseAltitude(int predClfDist, int diffClfMslHgt, int relTarHorDist, int | |||
| // Aim to attain cruise altitude as soon as possible while having the absolute value | |||
| // of vertical facing bound by the maximum vertical rate of turn | |||
| var vDist = new WVec(-diffClfMslHgt - info.CruiseAltitude.Length, -speed, 0); | |||
| desiredVFacing = (sbyte)vDist.HorizontalLengthSquared != 0 ? vDist.Yaw.Facing : vFacing; | |||
| desiredVFacing = (sbyte)(vDist.HasNonZeroHorizontalLength ? vDist.Yaw.Facing : vFacing); | |||
| @@ -702,7 +702,7 @@ int IncreaseAltitude(int predClfDist, int diffClfMslHgt, int relTarHorDist, int | |||
| // Aim to attain cruise altitude as soon as possible while having the absolute value | |||
| // of vertical facing bound by the maximum vertical rate of turn | |||
| var vDist = new WVec(-diffClfMslHgt - info.CruiseAltitude.Length, -speed, 0); | |||
| desiredVFacing = (sbyte)vDist.HorizontalLengthSquared != 0 ? vDist.Yaw.Facing : vFacing; | |||
| desiredVFacing = (sbyte)(vDist.HasNonZeroHorizontalLength ? vDist.Yaw.Facing : vFacing); | |||
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I've tested this myself, but couldn't reproduce those performance gains. With 197 bazookas, all shooting at exactly the same time, both times on the same map, same spawnpoint, same starting units, I couldn't see a visible difference in Tick rate, both times it maxed out at 10.x ms/tick. |
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This method of profiling is weird. |
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Closing, no useful gain with all the changes. |
It is common in current bleed that LengthSquared is compared with 0. In this case, it is faster to check if all elements are 0 than to perform sum of squared then compare with zero.