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https://github.com/hyprwm/Hyprland
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72 lines
No EOL
2.7 KiB
C++
72 lines
No EOL
2.7 KiB
C++
#include "BezierCurve.hpp"
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void CBezierCurve::setup(std::vector<Vector2D>* pVec) {
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m_dPoints.clear();
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const auto BEGIN = std::chrono::high_resolution_clock::now();
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m_dPoints.emplace_back(Vector2D(0,0));
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for (auto& p : *pVec) {
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m_dPoints.push_back(p);
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}
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m_dPoints.emplace_back(Vector2D(1,1));
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RASSERT(m_dPoints.size() == 4, "CBezierCurve only supports cubic beziers! (points num: %i)", m_dPoints.size());
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// bake BAKEDPOINTS points for faster lookups
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// T -> X ( / BAKEDPOINTS )
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for (int i = 0; i < BAKEDPOINTS; ++i) {
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m_aPointsBaked[i] = Vector2D(getXForT((i + 1) / (float)BAKEDPOINTS), getYForT((i + 1) / (float)BAKEDPOINTS));
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}
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const auto ELAPSEDUS = std::chrono::duration_cast<std::chrono::nanoseconds>(std::chrono::high_resolution_clock::now() - BEGIN).count() / 1000.f;
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const auto POINTSSIZE = m_aPointsBaked.size() * sizeof(m_aPointsBaked[0]) / 1000.f;
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const auto BEGINCALC = std::chrono::high_resolution_clock::now();
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for (float i = 0.1f; i < 1.f; i += 0.1f)
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getYForPoint(i);
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const auto ELAPSEDCALCAVG = std::chrono::duration_cast<std::chrono::nanoseconds>(std::chrono::high_resolution_clock::now() - BEGINCALC).count() / 1000.f / 10.f;
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Debug::log(LOG, "Created a bezier curve, baked %i points, mem usage: %.2fkB, time to bake: %.2fµs. Estimated average calc time: %.2fµs.",
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BAKEDPOINTS, POINTSSIZE, ELAPSEDUS, ELAPSEDCALCAVG);
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}
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float CBezierCurve::getYForT(float t) {
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return 3 * t * pow(1 - t, 2) * m_dPoints[1].y + 3 * pow(t, 2) * (1 - t) * m_dPoints[2].y + pow(t, 3);
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}
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float CBezierCurve::getXForT(float t) {
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return 3 * t * pow(1 - t, 2) * m_dPoints[1].x + 3 * pow(t, 2) * (1 - t) * m_dPoints[2].x + pow(t, 3);
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}
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// Todo: this probably can be done better and faster
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float CBezierCurve::getYForPoint(float x) {
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// binary search for the range UPDOWN X
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float upperT = 1;
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float lowerT = 0;
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float mid = 0.5;
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while(std::abs(upperT - lowerT) > INVBAKEDPOINTS) {
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if (m_aPointsBaked[((int)(mid * (float)BAKEDPOINTS))].x > x) {
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upperT = mid;
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} else {
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lowerT = mid;
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}
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mid = (upperT + lowerT) / 2.f;
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}
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// in the name of performance i shall make a hack
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const auto LOWERPOINT = &m_aPointsBaked[std::clamp((int)((float)BAKEDPOINTS * lowerT), 0, 199)];
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const auto UPPERPOINT = &m_aPointsBaked[std::clamp((int)((float)BAKEDPOINTS * upperT), 0, 199)];
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const auto PERCINDELTA = (x - LOWERPOINT->x) / (UPPERPOINT->x - LOWERPOINT->x);
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if (std::isnan(PERCINDELTA) || std::isinf(PERCINDELTA)) // can sometimes happen for VERY small x
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return 0.f;
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return LOWERPOINT->y + (UPPERPOINT->y - UPPERPOINT->y) * PERCINDELTA;
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} |