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ecurtiss / CatRom

Creates Catmull-Rom splines for Roblox
https://ecurtiss.github.io/CatRom/
Mozilla Public License 2.0
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Reuse vector computations during instantiation #20

Closed ecurtiss closed 2 months ago

ecurtiss commented 2 months ago

When parametrizing in Spline.new(), many of the vector subtractions and vector magnitudes can be reused across instantiations. This should reduce parametrization time significantly.

ecurtiss commented 2 months ago

Alternatively, a lerp-based algorithm like de Casteljau or Seiler interpolation would permit storing half the data that we currently store at the cost of slower computations.

ecurtiss commented 2 months ago

I wrote some horribly unreadable algorithms to reduce duplicate computations. I also included some special cases:

Parameter Value Parametrization name
alpha 0 uniform
alpha 0.5 centripetal
alpha 1 chordal
tension 1 taut

The following benchmarks show that the new methods are about 13-17% faster, with taut being ~65% faster. We also see that the perf improvements in chordal and centripetal decrease with the number of interpolants, so their value is questionable given the extra code paths that they add. As a result, I will nix chordal, but I will keep centripetal since it is the default.

instantiation-benchmark.zip

10 interpolants per spline, 100 instantiations per benchmark image

100 interpolants per spline, 10 instantiations per benchmark image

ecurtiss commented 2 months ago

Completely merged in 4a501aba8d4f54a3f5aa6f1c118ff05dcf2dabf7.