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Code Issues 123 Wiki Activity

state_manager: Optimize/unify track curve derivative computation (#147)

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In TSegment there were two different formulas for a derivative. Most places called GetFirstDerivative() that used the direct formula from the curve points. However RaPositionGet() had its own calculation based on pre-computed cubic polynomial coefficients. This latter method is faster and simpler, so change GetFirstDerivative() to use it and change RaPositionGet() to just call GetFirstDerivative().
This commit is contained in:
combolek
2026-07-19 15:02:02 -07:00
committed by GitHub
parent b17a86bc18
commit c8e5360d87
1 changed files with 4 additions and 17 deletions
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21
world/Segment.cpp
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@@ -163,21 +163,8 @@ void TSegment::InitTFromSInterpolateData()
glm::dvec3 TSegment::GetFirstDerivative(double const fTime) const glm::dvec3 TSegment::GetFirstDerivative(double const fTime) const
{ {
// derivative is 3*A*t^2 + 2*B*t + C
double fOmTime = 1.0 - fTime; return fTime * ( fTime * 3.0 * vA + vB + vB ) + vC;
double fPowTime = fTime;
glm::dvec3 kResult = fOmTime * (CPointOut - Point1);
// int iDegreeM1 = 3 - 1;
double fCoeff = 2 * fPowTime;
kResult = (kResult + fCoeff * (CPointIn - CPointOut)) * fOmTime;
fPowTime *= fTime;
kResult += fPowTime * (Point2 - CPointIn);
kResult *= 3;
return kResult;
} }
double TSegment::RombergIntegral(double const fA, double const fB) const double TSegment::RombergIntegral(double const fA, double const fB) const
@@ -385,8 +372,8 @@ void TSegment::RaPositionGet(double const fDistance, glm::dvec3 &position, glm::
position = FastGetPoint( t ); position = FastGetPoint( t );
// przechyłka w danym miejscu (zmienia się liniowo) // przechyłka w danym miejscu (zmienia się liniowo)
rotation.x = std::lerp( fRoll1, fRoll2, t ); rotation.x = std::lerp( fRoll1, fRoll2, t );
// pochodna jest 3*A*t^2+2*B*t+C // pochodna
auto const tangent = t * ( t * 3.0 * vA + vB + vB ) + vC; auto const tangent = GetFirstDerivative( t );
// pochylenie krzywej (w pionie) // pochylenie krzywej (w pionie)
rotation.y = std::atan( tangent.y ); rotation.y = std::atan( tangent.y );
// kierunek krzywej w planie // kierunek krzywej w planie