diff --git a/src/helpers/BezierCurve.cpp b/src/helpers/BezierCurve.cpp index 85e71f71..54a18732 100644 --- a/src/helpers/BezierCurve.cpp +++ b/src/helpers/BezierCurve.cpp @@ -18,7 +18,7 @@ void CBezierCurve::setup(std::vector* pVec) { // bake BAKEDPOINTS points for faster lookups // T -> X ( / BAKEDPOINTS ) for (int i = 0; i < BAKEDPOINTS; ++i) { - m_aPointsBaked[i] = getXForT((i + 1) / (float)BAKEDPOINTS); + m_aPointsBaked[i] = Vector2D(getXForT((i + 1) / (float)BAKEDPOINTS), getYForT((i + 1) / (float)BAKEDPOINTS)); } const auto ELAPSEDUS = std::chrono::duration_cast(std::chrono::high_resolution_clock::now() - BEGIN).count() / 1000.f; @@ -45,25 +45,28 @@ float CBezierCurve::getXForT(float t) { // Todo: this probably can be done better and faster float CBezierCurve::getYForPoint(float x) { // binary search for the range UPDOWN X - float upperX = 1; - float lowerX = 0; + float upperT = 1; + float lowerT = 0; float mid = 0.5; - while(std::abs(upperX - lowerX) > INVBAKEDPOINTS) { - if (m_aPointsBaked[((int)(mid * (float)BAKEDPOINTS))] > x) { - upperX = mid; + while(std::abs(upperT - lowerT) > INVBAKEDPOINTS) { + if (m_aPointsBaked[((int)(mid * (float)BAKEDPOINTS))].x > x) { + upperT = mid; } else { - lowerX = mid; + lowerT = mid; } - mid = (upperX + lowerX) / 2.f; + mid = (upperT + lowerT) / 2.f; } // in the name of performance i shall make a hack - const auto PERCINDELTA = (x - m_aPointsBaked[(int)((float)BAKEDPOINTS * lowerX)]) / (m_aPointsBaked[(int)((float)BAKEDPOINTS * upperX)] - m_aPointsBaked[(int)((float)BAKEDPOINTS * lowerX)]); + const auto LOWERPOINT = &m_aPointsBaked[(int)((float)BAKEDPOINTS * lowerT)]; + const auto UPPERPOINT = &m_aPointsBaked[(int)((float)BAKEDPOINTS * upperT)]; + + const auto PERCINDELTA = (x - LOWERPOINT->x) / (UPPERPOINT->x - LOWERPOINT->x); if (std::isnan(PERCINDELTA) || std::isinf(PERCINDELTA)) // can sometimes happen for VERY small x return 0.f; - return getYForT(mid + PERCINDELTA * INVBAKEDPOINTS); + return LOWERPOINT->y + (UPPERPOINT->y - UPPERPOINT->y) * PERCINDELTA; } \ No newline at end of file diff --git a/src/helpers/BezierCurve.hpp b/src/helpers/BezierCurve.hpp index 72463119..da01b688 100644 --- a/src/helpers/BezierCurve.hpp +++ b/src/helpers/BezierCurve.hpp @@ -23,5 +23,5 @@ private: // this INCLUDES the 0,0 and 1,1 points. std::deque m_dPoints; - std::array m_aPointsBaked; + std::array m_aPointsBaked; }; \ No newline at end of file