35 lines
1.1 KiB
C
35 lines
1.1 KiB
C
/*
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* Copyright (c) 2019 Andri Yngvason
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
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* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
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* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
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* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
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* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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* PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "smooth.h"
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#include "time-util.h"
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#include <math.h>
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double smooth(struct smooth* self, double input)
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{
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uint64_t now = gettime_us();
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double dt = (now - self->last_time) * 1.0e-6;
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self->last_time = now;
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double factor = 1.0 - exp(-dt / self->time_constant);
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double result = factor * input + (1.0 - factor) * self->last_result;
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self->last_result = result;
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return result;
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}
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