stroke_samples()

void MayaFlux::Kinesis::stroke_samples ( std::span< float >  samples, std::optional< size_t > &  previous, float  position, float  level  )

inlinenoexcept

Write a level into an evenly spaced sample array at a fractional position, filling linearly from the previously written index.

position in [0, 1] selects the index (0 is the first sample, 1 the last). level is clamped to [0, 1]. When previous holds a different valid index, every sample between that index and the new one is set on the line from the value last stored at previous to level, in either direction, so a fast gesture leaves no gaps. previous is updated to the index just written; reset it to clear the gesture.

A NaN position selects the first sample; infinite positions clamp to the nearest end. An empty array is untouched.

Parameters

samples	Samples to write into.
previous	Index written by the previous call of this gesture.
position	Fractional position in [0, 1].
level	Level in [0, 1].

Definition at line 24 of file Stroke.hpp.

{
    if (samples.empty())
        return;
 
    if (std::isnan(position))
        position = 0.F;
 
    const size_t last = samples.size() - 1;
    const size_t index = static_cast<size_t>(std::clamp(position, 0.F, 1.F) * static_cast<float>(last));
    const float target = std::clamp(level, 0.F, 1.F);
 
    if (previous && *previous != index && *previous <= last) {
        const size_t from = *previous;
        const float start = samples[from];
        const size_t lo = std::min(from, index);
        const size_t hi = std::max(from, index);
        const auto run = static_cast<float>(hi - lo);
 
        for (size_t i = lo; i <= hi; ++i) {
            const size_t travelled = i > from ? i - from : from - i;
            const float fraction = static_cast<float>(travelled) / run;
            samples[i] = start + (target - start) * fraction;
        }
    } else {
        samples[index] = target;
    }
 
    previous = index;
}

References index, position, and run().

Referenced by MayaFlux::Portal::Forma::Geometry::wire_canvas_drag().

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