bezier: Optimize CBezierCurve::getYForPoint (#3321)

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Dickby 2023-09-16 19:32:33 +02:00 committed by GitHub
parent d126d2c092
commit a53ec98b82
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@ -48,27 +48,25 @@ float CBezierCurve::getXForT(float t) {
// Todo: this probably can be done better and faster
float CBezierCurve::getYForPoint(float x) {
if (x >= 1.0)
return 1.0;
if (x >= 1.f)
return 1.f;
// binary search for the range UPDOWN X
int upperT = BAKEDPOINTS - 1;
int lowerT = 0;
int mid = upperT / 2;
int index = 0;
bool below = true;
for (int step = (BAKEDPOINTS + 1) / 2; step > 0; step /= 2) {
if (below)
index += step;
else
index -= step;
while (std::abs(upperT - lowerT) > 1) {
if (m_aPointsBaked[mid].x > x) {
upperT = mid;
} else {
lowerT = mid;
below = m_aPointsBaked[index].x < x;
}
mid = (upperT + lowerT) / 2;
}
int lowerIndex = index - (!below || index == BAKEDPOINTS - 1);
// in the name of performance i shall make a hack
const auto LOWERPOINT = &m_aPointsBaked[std::clamp(lowerT, 0, BAKEDPOINTS - 1)];
const auto UPPERPOINT = &m_aPointsBaked[std::clamp(upperT, 0, BAKEDPOINTS - 1)];
const auto LOWERPOINT = &m_aPointsBaked[lowerIndex];
const auto UPPERPOINT = &m_aPointsBaked[lowerIndex + 1];
const auto PERCINDELTA = (x - LOWERPOINT->x) / (UPPERPOINT->x - LOWERPOINT->x);